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Influence of aridity on reproduction of the collared peccary (Dicotyles tajacu (linn)) in Texas Low, William A 1970

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THE INFLUENCE OF ARIDITY ON REPRODUCTION OF THE COLLARED PECCARY (PICOTYLES TAJACU (LINN)) IN TEXAS  by  B.Sc.  WILLIAM A. LOW (Honours), U n i v e r s i t y o f B r i t i s h Columbia,  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY  i n t h e Department of Zoology  We a c c e p t t h i s t h e s i s as conforming t o t h e required standard  THE UNIVERSITY OF BRITISH COLUMBIA 1970  1962  In p r e s e n t i n g t h i s  thesis  an advanced degree at the L i b r a r y I  in p a r t i a l  the U n i v e r s i t y  s h a l l make i t  freely  f u l f i l m e n t o f the of B r i t i s h  available  for  requirements f o r  Columbia, I agree  that  reference and study.  f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e copying o f t h i s  thesis  f o r s c h o l a r l y purposes may be granted by the Head o f my Department o r by h i s of  representatives.  this  It  thesis for financial  i s understood that copying o r p u b l i c a t i o n gain s h a l l  written permission.  Department o f  Zoology  The U n i v e r s i t y o f B r i t i s h Columbia Vancouver 8, Canada  Date  October 26.  1970  not be allowed without my  i i  ABSTRACT  ' Reproduction  and  productivity  of the c o l l a r e d  t a j a c u a n g u l a t u s , were e x a m i n e d i n T e x a s u n d e r m o i s t and  in captivity  under presumed o p t i m a l  F o e t a l sex r a t i o s Iy  after birth,  and  Texas p o p u l a t i o n . in  Life  and  draught  conditions,  conditions.  f a v o u r females,laut change t o f a v o u r males s h o r t -  again f a v o u r females  Texas p o p u l a t i o n c o n t a i n e d  peccary, D i c o t y l e s  i n t h e o l d e r age  classes.  a higher proportion of o l d e r animals  expectancy  south Texas p e c c a r i e s , and  at  1 y e a r o f age  the average  annual  was  The  than  south  the  e s t i m a t e d a t 3.0  mortality  r a t e was  west years  21.5°/o.  z  The  m o r t a l i t y r a t e f o r w e s t T e x a s p e c c a r i e s was c a l c u l a t e d a t 27.5°/>. i A n i m a l c o n d i t i o n , e s t i m a t e d from k i d n e y f a t and c a r c a s s weight,was h i g h e s t i n t h e l a t e f a l l , a n d was s i g n i f i c a n t l y b e t t e r i n t h e y e a r o f h i g h i  rainfall  and  good r a n g e c o n d i t i o n s t h a n  during the  drought  year.  of  t h e s o u t h T e x a s p e c c a r i e s u n d e r g o o d r a n g e c o n d i t i o n s was  as  that of pen-reared  as  t h e w e s t T e x a s p e c c a r i e s u n d e r gao'd  a n i m a l s , and  under drought  wild  p o p u l a t i o n s do  animals two  h^ve  of  a fertile  lifters  evidence  not  a year.  Although  constituents,  some m a l e s a t a l l t i m e s o f t h e  high low  there  abundant  become p r e g n a n t p o s t - p a r ^ u m and  until  are  sperm  year.  mature a t j u s t ' under a yearj, but 16 t o 20 months'.  l a c t a t i o n oestruses,; and  i n the  Pen-raised generally, nroduce  I n s o u t h ' T e x a s 33°//ofj t h e a d u l t sows s h o w e d o v a r i a n  of consecutive pregnancies.'  the c o l l e c t e d  as  conditions.  s e a s o n a l changes i n the p r o p o r t i o n of t e s t i s  Females appear s e x u a l l y  almost  c o n d i t i o n s a l i s o s t as  M a l e s m a t u r e s e x u a l l y pt^, j u s t u n d e r a y e a r .  are present i n at l e a s t  Condition  s o w s we're pre.gnant  D u r i n g f a v o u r a b l e r a n g e ' c o n d i t i o n s 71°/o  and  41°/o had' r e m a t e d .  c o n d i t i o n s o n l y 2670 o f t h e s o w s w e r e p r e g n a n t a n d 9% i m e a s u r e o f c o n s e c u t i v e p r e g n a n c i e s i n , w e s t T e x a s was  i  During  drought  remated. A good t not o b t a i n e d , but i t  i  aopears comparable t o s o u t h Texas under drought c o n d i t i o n s . T h e r e was no \ I aDparent decrease i n r e p r o d u c t i o n i n 15-year o l d s o u t h Texas and 9-year o l d ;  west Texas  ;  female's Thjere was  late, s p r i n g  Texas.  i s limited  f o r west T e x a s , b u t most c o n c e p t i o n s o c c u r i n  Good r a n g e c o n d i t i o n s a r i s i n g  i n early  A  w i n t e r b r e e d i n g and  Drought c o n d i t i o n s r e t a r d  eliminate  in  f ;  winter.  result  andj a m i n o r one  i n s o u t h Texas.Evidence  late  a major breeding period i n mid-winter  laise s p r i n g .breeding.  from  strong^ spring  the 1  f a v o u r a b l e r a i n f a l l , Dattjernsj br^ee.ding a c t i v i t y  w i n t e r breeding season'and  i n south'  almos^t  i i i .  Gross p r o d u c t i v i t y sows. study.  p e n n e d a n i m a l s was  S o u t h T e x a s sows a v e r a g e d 240 No  conditions d r o u g h t 151  adult  sows d u r i n g  the  gross productivity  s o w s , and  was  288  young/100 a d u l t  range  during  the  young/100 adult, sows. productivity  T e x a s t h e r e w e r e 45 Predstion  two  young/100 a d u l t  young/1OD  D u r i n g good  1-year olds/100 a d u l t  populations.  425  measure i s a v a i l a b l e f o r west Texas sows.  Net  29°/o o f  of  i n south Texas d u r i n g the  sows and  53  (yearlings)/l00  (yearlings)/l00 and  parasitism  Combined c o l d h e r d s , and  could  adult are  s t u d y was  adult  sows.  drought r e s u l t e d  function  a factor controlling  primary c o n t r o l l i n g f a c t o r of  In  west  minor importance to  w e a t h e r and  D r a u g h t , t h r o u g h i t s e f f e c t on  under-  sows.  probably of  as  81  i n a decrease  food a v a i l a b i l i t y ,  peccary populations i n  Texas.  the of  populations. a p p e a r s t o be  the  iv.  TABLE OF CONTENTS ABSRACT . LIST OF FIGURES LIST OF TABLES LIST OF PLATES ACKNOWLEDGEMENTS  i i vi viii xi xiii  1. 2.  INTRODUCTION STUDY AREAS 2.1. Physiography 2.2. Climate 2.3. Vegetation 2.4. Competitors and predators  1 4 4 6 14 18  3.  MATERIALS AND METHODS 3.1. Collected animals 3.2. Live trapping 3.3. F i e l d observations 3.4. Pen-reared animals 3.5. Age determination 3.6. Sex determination 3.7. Census 3.8. Food habits 3.9. Growth 3.10. Condition 3.11. Male reproduction 3.12. Female reproduction 3.13. S t a t i s t i c a l treatment  20 20 21 22 23 23 24 24 25 25 26 26 27 29  4.  RESULTS 4.1. Food habits  30 30  4.2.  Condition  4.3.  Growth  35  4.4.  The population 4.4.1. Density 4.4.2. Home range and movements 4.4.3. Population structure Sex r a t i o Age structure Male reproduction 4.5.1. Morphology of the male reproductive t r a c t 4.5.2. Growth and seasonal change i n t e s t i s size 4.5.3. H i s t o l o g i c a l examination of testes 4.5.4. Seasonal changes i n h i s t o l o g i c a l structure of testes Female reproduction 4.6.1. The reproductive tract and mammae 4.6.2. The ovary 4.6.3. The reproductive cycle Oestrous period and cycle Gestation period Frequency of gestation 4.6.4. Maturation  45 45 46 47 47 48 52 52 52 60 63 55 65 65 77 77 79 79 81  4.5.  4.6.  30  V.  4.7.  4.6.5. S e n i l i t y 4.6.6. Breeding Season 4.6.7. L i t t e r S i z e Productivity 4.7.1. Ovulation incidence 4.7.2. Implantation incidence 4.7.3. Ovulation and implantation rates 4.7.4. P r o d u c t i v i t y of age classes 4.7.5. Gross and net p r o d u c t i v i t y  83 84 90 90 90 93 95 95 97  5.  DISCUSSION  100  6.  APPENDIX  120  A. B. C.  121 123 125 125 143 148  D. E. F. G.  L i s t of s c i e n t i f i c names Handling trapped and captive peccaries Age determination of peccaries 1. Young and adult peccaries 2. Foetal peccaries Age-specific body measurements and weights of south and west Texas male and female peccaries Spermatogenic a c t i v i t y of a selected s e r i e s of testes from the '-. c o l l a r e d peccary A g e — s p e c i f i c s i z e of ovaries and ovarian s t r u c t u r e s M o r t a l i t y f a c t o r s a f f e c t i n g peccary populations  7.  LITERATURE CITED  8.  BIOGRAPHICAL INFORMATION  J  150 152 155 161  . 1 7 0  vi.  LIST OF FIGURES 1.  Location of the study areas, and r a i n f a l l and evaporation d i s t r i b u t i o n i n Texas.  5  2.  Monthly average, maximum, and minimum temperatures f o r four areas. a. K i n g s v i l l e b. Welder Refuge c. Watson Ranch d. Black Gap  8  3.  Deviation of monthly r a i n f a l l from the long-term monthly averages on the King Ranch and Welder Refuge.  9  4.  Deviation of monthly r a i n f a l l from the long-term monthly aver-  10  age near the Watson Ranch and Black Gap areas. 5.  A r i d i t y index f o r the Welder Refuge.  12  6.  Forage c l a s s composition of the stomach contents of 73 c o l l a r e d peccaries from south Texas. Seasonal changes i n kidney f a t index i n south Texas peccaries during moist and drought conditions, 1965-1967.  32  8.  R e l a t i o n s h i p of l i v e weights to age of pen-reared and c o l l e c t e d south Texas peccaries.  38  9.  Comparison of carcass weights of south and west Texas male peccaries by year c l a s s .  10.  Comparison of carcass weights of south and west Texas female peccaries by year c l a s s .  40  11.  Live and carcass weights of trapped and c o l l e c t e d female pecc a r i e s o l d e r than two years.  43  12.  Live and carcass weights of trapped and c o l l e c t e d male pec-  44  7.  34  > 40  c a r i e s o l d e r than two years. 13.  Age d i s t r i b u t i o n of peccaries c o l l e c t e d i n south and west Texas.  14.  Change i n t e s t i s index (T.I.) with age of south and west Texas males. 56  15.  Seasonal change i n t e s t i s index of adult south Texas males.  56  16.  Change i n t e s t i s index, sperm counts, proportion of tubules, and tubule diameter with age of south Texas males. Seasonal changes i n t e s t i s s i z e and h i s t o l o g i c a l s t r u c t u r e s of 18 adult south Texas males.  62  17.  49  64  18.  Seasonal changes i n s i z e of ovarian medulla f o r a l l sows two years and o l d e r c o l l e c t e d i n south Texas.  19.  Change i n volume of the corpus luteum of pregnancy with progress of g e s t a t i o n period.  20.  Regression of the corpus luteum of pregnancy a f t e r p a r t u r i t i o n .  21.  Seasonal changes i n breeding a c t i v i t y of adult female peccaries i n south Texas.  22.  Month of b i r t h of young i n south Texas.  23.  Month of b i r t h of young i n west Texas.  24.  Factors a f f e c t i n g peccary populations.  25.  Model of process of population change i n south Texas peccary populations. Appendix C. Fig. 1  Lens weight d i s t r i b u t i o n by a) age class and b) annulation age of south Texas peccaries.  Fig. 2  Regression of lens weight on age of known-age peccaries<21 months o l d and of a l l south Texas peccaries < 24 months o l d .  Fig. 3  Tooth eruption progression f o r south Texas peccaries.  Fig. 4  Comparison of age determined by dental annulations and wear c l a s s f o r south and west Texas peccaries.  Fig. 5  Crown-rump growth curves of f o e t a l domestic p i g and blackt a i l e d deer p l o t t e d i n the same i n t e r v a l and used "'for p r e d i c t i n g the age of f o e t a l peccaries.  viii.  LIST OF TABLES Table. 7 .35 35  1.  Climate-logical c h a r a c t e r i s t i c s of the four study areas.  2.  Comparison of F a l l kidney f a t i n d i c e s of adult captive, south Texas, and west Texas peccaries under d i f f e r e n t moisture conditions .  3.  Weights of pen—raised and w i l d neonatal  4.  S i z e comparison of adult peccaries from south and west Texas.  41  5.  Comaprison of carcass weights of adult south and west Texas peccaries between low- and h i g h - r a i n f a l l periods.  42  6.  Peccary density estimates i n Mesquite Pasture of the King pianch, from s t r i p census.  7.  Peccary density estimates on the four study areas i n south and west Texas.  46  8.  Age-specific sex r a t i o s of pen-born, south Texas, and west Texas peccaries.  47  9.  Age-specific sex r a t i o s of young south Texas peccaries conceived or born i n d i f f e r e n t c l i m a t i c conditions.  48  10.  L i f e Table f o r south Texas peccaries based on 218 peccaries.  51  peccaries.  36  -45  11 . L i f e Table f o r west Texas peccaries older than 12 months, based on 102 peccaries.  51  12.  Growth of testes of south Texas peccaries.  52  13.  Age—specific t e s t i s i n d i c e s f o r adult south Texas males.  57  14.  Growth of testes of west Texas peccaries.  57  15.  Age s p e c i f i c t e s t i s i n d i c e s f o r adult west .Texas males.  58  16.  T e s t i s i n d i c e s of pen-^reared peccaries.  59  17.  T e s t i s i n d i c e s of adult south Texas peccaries compared by r a i n f a l l levels.  59  18.  T e s t i s i n d i c e s of adult west Texas peccaries compared by month and year.  60  19.  I n t e r v a l between p a r t u r i t i o n and f e r t i l e oestrus i n pen-reared peccaries.  80  Table. 20.  Incidence of consecutive pregnancies i n south and west Texas peccaries.  21.  Behavioral maturation of female pen-reared peccaries.  22.  L i t t e r s i z e i n peccaries.  23.  Age-specific pregnancy, o v u l a t i o n , and implantation incidences of captive, south Texas, and west Texas peccaries. Seasonal o v u l a t i o n and implantation incidences, and reproductive index of adult south Texas peccaries.  24. 25.  Proportion of adult sows showing evidence of consecutive pregnancies i n south and west Texas during drought and high r a i n f a l l periods.  26.  P r o d u c t i v i t y of adult south Texas peccaries.  27.  Proportion of young observed i n population at monthly and quarterly i n t e r v a l s . Peccary density estimates on the King Ranch  28.  Appendix B. Table  1.  T r a n q u i l i z i n g and immobilizing drugs, and successful dosages used on penned and trapped peccaries.  Appendix C. Table 1. Comparison of known—age and annulation—age of peccaries pen-reared by L.K. Sowls i n Arizona and during t h i s study at U.B.C. and the Welder Refuge. Table  2.  Estimate of ages and conception dates of f o e t a l peccaries from crown-rump length and weight.  Appendix D. Table  1,  Age-specific weight and body measurements of peccaries c o l l e c t e d i n south Texas.  Table  2.  Age-specific weight and body measurements of peccaries c o l l e c t e d i n west Texas.  Appendix Table  1.  E. Spermatogenic a c t i v i t y of a selected s e r i e s of testes from the c o l l a r e d peccary.  X.  Appendix F. Table  1.  Age—specific weights and volumes of ovaries and ovarian s t r u c t u r e s of pregnant and non-pregnant south Texas peccaries.  153  Table  2.  Age—specific weights and volumes of voaries and ovarian structures of pregnant and non-pregnant west Texas peccaries.  154  Appendix  G.  Table 1.  Stomach contents of canid and f e l i d predators trapped on the Santa Gertrudis d i v i s i o n , ' K i n g Ranch.  155  Table 2.  Cause of death of peccaries found dead i n south Texas.  156  Table 3.  Prevalence and abundance of parasites of the c o l l a r e d peccary i n Texas.  158  LIST OF PLATES  Frontispiece  C o l l a r e d peccary feeding i n a p r i c k l y pearhalophyte community.  1.  Representative peccary habitat i n south and west Texas a. One-year o l d root-plowed c h a p a r r a l - p r i c k l y pear community on the King Ranch i n south Texas. b. Several-year o l d root-plowed c h a p a r r a l - p r i c k l y pear community on the King Ranch. c. A densely vegetated community of the lowland desert scrub a s s o c i a t i o r r . i n west Texas.  2.  The male reproductive t r a c t a. The e n t i r e t r a c t . b. Cross-section of the t e s t i s one-third of the distance from the caput epididymis. c. Cross-section of the t e s t i s i n the c e n t r a l region. d. Cross-section of the t e s t i s one-third of the distance from the cauda epididymis.  3.  The female reproductive t r a c t a. Reproductive t r a c t of a pregnant b. Ovary from non-pregnant sow. c. Ovary with two corpora l u t e a . d. Ovary with one corpus luteum.  4.  Ovaries and ovarian s t r u c t u r e s a. Ovary of an 82-day post-conception foetus. b. Ovary of neonatal peccary. c. L i p o c y t i c c e l l s adjacent to ovarian medulla i n adult female ovary. d. Tubule i n ovarian medulla of 9—year o l d west Texas sow. e. I n t e r s t i t i a l c e l l s of ovarian medulla of non—pregnant f. g. h.  5.  sow.  sow.  I n t e r s t i t i a l c e l l s of t e s t i s of adult male. The r e t e o v a r i i i n a 9—year o l d west Texas sow. The r e t e o v a r i i i n a f o e t a l ovary.  Ovarian s t r u c t u r e s a. P r i m o r d i a l f o l l i c l e s i n band around periphery of cortex. b. Ovarian medulla of pregnant sow. c. Ovarian medulla of non-pregnant sow. d. C o r t i c a l s t r u c t u r e s of an adult ovary. e. Degenerating CL-NP. f. Degenerating CL-P. g. Involuted appearance of r a p i d l y growing CL-P.  xii.  h.  Granulosa  i.  Scar  Appendix  C.  P l a t e 1.  Annulations a. b. c. d.  luteal  c e l l s i n non-viable  o f past pregnancy  (corpus  corpus  luteum.  albicans).  i n t o o t h cementum.  T h e m e t h o d o f c o u n t i n g a n n u l a t i o n s i n t h e cementum of the f i r s t incisor. S t r o n g a n n u l a t i o n s i n t h e cementum o f a n 8 - y e a r o l d female (P-12). Weak a n n u l a t i o n s i n t h e cementum o f a 6 - y e a r o l d f e m a l e (P-14). F a i n t a n d s t r o n g a n n u l a t i o n s i n t h e cementum o f a 10-year o l d female (P-81).  140  xiii.  ACKNOWLEDGEMENTS Many people gave k i n d l y of t h e i r time, assistance and advice during t h i s p r o j e c t .  I t i s impossible to mention a l l of them here and to  those not s p e c i f i c a l l y mentioned I am g r a t e f u l f o r t h e i r help. I am p a r t i c u l a r l y indebted to Dr. Ian McTaggart Cowan f o r suggesting and f o r c o n s t r u c t i v e c r i t i c i s m of the study, providing funds f o r equipment and expenses, g i v i n g encouragement during times of f r u s t r a t i o n and f o r bearing with me during the long g e s t a t i o n and d i f f i c u l t b i r t h of this thesis. Dr. Clarence Cottam, D i r e c t o r , and Mr. W.C.  Glazener, A s s i s t a n t  D i r e c t o r , of the Welder W i l d l i f e Refuge provided many h e l p f u l suggestions and c r i t i c i s m s from the conception of the study.  I am g r a t e f u l to them  and to the t r u s t e e s of the Welder W i l d l i f e Foundation f o r providing l i v i n g quarters, equipment a .d e x t r a help when i t was needed. The Welder Refuge s t a f f , students, v i s i t o r s , summer a s s i s t a n t s and t h e i r f a m i l i e s were extremely h e l p f u l .  Olney Maley, Ruby Lou Hranicky,  Celso V i l l a r e a l , Anne Speers, W i l l n a Glazener, J e f f K i r b y and Jack I n g l i s helped i n various ways.  Students Dean Chamrad, Marshall White, E r i c Bolen,  Bob Cook, J e f f Powell, Duane G a l l , Lynne Drawe, and Ron Hood, long-term v i s i t o r s Thadis Box, Walter Robertson, John T. Emlen, J r . and Richard Heape, summer a s s i s t a n t s Ken Matocha, Bruce F a l l , Mike Fleming, the C a s t i l l o brothers, Alonzo and G i l b e r t o , and John Beecham a l l provided i n formation, advice or a s s i s t a n c e . B i l l Samuel and Rick White, r e s p e c t i v e l y , undertook j o i n t studies of p a r a s i t e s and food h a b i t s , which added important information to the study.  I p a r t i c u l a r l y enjoyed and appreciate the many  hours that Bob Watts put i n helping with f i e l d work and autopsies and d i s cussing various aspects of the study.  His enthusiasm was s t i m u l a t i n g .  Numerous r e s i d e n t s of the Sinton area made my stay i n Texas enjoyable.  Debbo and Momma I I F e a t h e r l i n g w i l l always be remembered. Mr. Valgene W. Lehmann, W i l d l i f e B i o l o g i s t f o r the King Ranch,  aided i n the conception of the study.  I appreciate the a i d which he  provided i n obtaining approval of the King Ranch, Inc. f o r much of the study to be conducted on the Ranch.  I wish to thank the King Ranch, Inc. and  Mr. Robert J . Kleberg, J r . , president, f o r providing permission, traps, b a i t , personnel and c l i m a t i c data used during the study.  Mr. W i l l i a m H.  xiv.  K i e l , J r . , and the W i l d l i f e crew f a c i l i t a t e d  various aspects of the f i e l d  study on the King Ranch. I am p a r t i c u l a r l y g r a t e f u l to George Schacherl, then predatory animal trapper on the King Ranch, f o r the many hours of companionship and help i n the f i e l d .  Few men are more dedicated and conscientious than  he. The s t a f f and students at Texas A & I U n i v e r s i t y , p a r t i c u l a r l y the W i l d l i f e Biology c l a s s , provided u s e f u l discussion and c r i t i c i s m . Mrs. Ralph Watson, and her daughter Mrs. Cardin, very k i n d l y granted permission to me to c o l l e c t peccaries on the ranch south of Ozona. I g r e a t l y appreciated the accommodation provided while Bobbi and I stayed there. Members of the Texas Parks and W i l d l i f e Dept. provided c o l l e c t i n g permits and h e l p f u l suggestions.  P i e r c e Uzzel i n A u s t i n , and the Black  Gap crew, Sam Brownlee, Durward ( E l Diablo) Avery, Tommy H a i l e y , and the C.O.s  and b i o l o g i s t s assigned to the p u b l i c hunt were p a r t i c u l a r l y h e l p f u l . Dr. L. K. Sowls k i n d l y provided teeth from known—age peccaries  r a i s e d during h i s study of peccaries i n Arizona.  He a l s o provided u s e f u l  discussion at the outset of the study. Many students and f a c u l t y at the U n i v e r s i t y of B.C. h e l p f u l suggestions.  provided  Drs. D. C h i t t y , V. J . K r a j i n a , A. J . Wood, J . Adams  and J . F. Bendell served as my t h e s i s committee and I appreciated t h e i r constructive c r i t i c i s m .  Dr. J . M. Taylor provided u s e f u l suggestions dur-  ing the termination of the study and Dr. P. J . L a r k i n provided h e l p f u l s t a t i s t i c a l information, p a r t i c u l a r l y on m o r t a l i t y r a t e s .  Many of the  Zoology s t a f f have been very h e l p f u l ; I p a r t i c u l a r l y appreciate the conscientious e f f o r t s of Armand Tepper In. looking a f t e r the peccaries r a i s e d at U.B.C., and of Gladys Welsby i n keeping the a d m i n i s t r a t i v e part of the study going smoothly while I was i n Texas and at U.B.C. Don Thomas was p a r t i c u l a r l y h e l p f u l with the ovarian a n a l y s i s , and I have enjoyed many hours of discussion with him.  Don Eastman and Lynne Kemper helped  with various aspects of the study.  I am g r a t e f u l to Dr. P. J . Bandy f o r  his many forms of help on t h i s and past p r o j e c t s , and to "the B.C.  Fish  and W i l d l i f e Branch f o r support during my early graduate research. Members of the Rangelands Research Unit, CSIRO, p a r t i c u l a r l y Mr. Ray Perry, were h e l p f u l during the f i n a l w r i t e up.  XV.  I thank A l i c e Thomas f o r her many re-typings of the d r a f t s of the t h e s i s , and Boyne Carragher f o r typing the f i n a l d r a f t . During the study I was supported by N.R.C. and U.B.C. Fellowships . Last, and probably most, I thank my wife, Bobbi, f o r her cont i n u i n g support and encouragement, f o r many discussions of various aspects of the study, f o r her u n s e l f i s h a i d i n a l l aspects of f i e l d and l a b o r a t o r y work, f o r c o n s t r u c t i v e l y c r i t i c i s i n g the various d r a f t s , and f o r drawing the f i g u r e s i n the t h e s i s .  I t i s not possible to express adequately my  appreciation to her f o r her e f f o r t s on my behalf.  xvi.  In presenting  t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of the requirements f o r  an advanced degree at the U n i v e r s i t y of B r i t i s h Columbia, I agree that the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r reference and study. I f u r t h e r agree that permission f o r extensive f o r s c h o l a r l y purposes may by h i s representatives.  copying of t h i s t h e s i s  be granted by the Head of my Department or I t i s understood that copying or p u b l i c a t i o n  of t h i s t h e s i s f o r f i n a n c i a l gain s h a l l not be allowed without my w r i t t e n permission.  Department of Zoology The U n i v e r s i t y of B r i t i s h Columbia Vancouver 8, Canada  1.  THE  1.  INFLUENCE OF ARIDITY ON REPRODUCTION OF THE COLLARED PECCARY (PICOTYLES TAJACU (LINN.)) IN TEXAS  INTRODUCTION Climatic forces, as the immediate cause of short term, large scale  losses to domestic and wild ungulates, are well known.  It has also been  shown that certain species, such as caribou (Rangifer) l i v i n g i n regions where c l i m a t i c hazards occur frequently, can experience imbalance of reproductive input against mortality through a span of years that renders management f o r a crop tenuous ( K e l s a l l , 1969).  Andrewartha and Birch (1954)  have suggested that such environmental forces acting i n a non-density dependent manner may  sometimes act as e f f e c t i v e regulators of animal numbers. The c o l l a r e d peccary (Dicotyles tajacu (Linn.)) in the United  i s at the northern  extremity of i t s range.  Here i t occupies an a r i d  environment i n which r a i n f a l l i s i r r e g u l a r , and lengthy and frequent of drought occur.  States  The species has occupied  periods  the region since early Recent  times and appears to maintain a density f l u c t u a t i n g around r e l a t i v e l y  low  levels. The ecology of the Sonoran c o l l a r e d peccary (D. t. sonoriensis (Mearns)) has been studied since 1956 Arizona. 1966;  by L.K.Sowls and his associates i n  A number of publications have arisen from t h i s research (Bigler,  Brown, et a l . , 1963;; Neal, 1959a and b; Eddy, 1961;  Sowls, 1962; 1961).  Sowls, 1961a, b; Sowls, et a l . , 1961;  Kirkpatrick and  and Sowls and Minamon,  These have included an extensive study of reproduction  Several other reports, noteably  (Sowls, 1966).  those of Jennings and Harris (1953), Knipe,  (1958) and Leopold (1959) have been concerned with the ecology of the collared peccary i n Texas, Arizona, and Mexico, respectively.  Ellisor  and  Harwell (1969) have recently studied the home range in the species in south Texas. Despite t h i s previous work, Sowls  1  (1961 a) statement that  "one  of the l e a s t known phases of the l i f e history of the c o l l a r e d peccary i s it's rate of increase" was  s t i l l largely true when I began my studies in  This unknown sector included potential reproduction i n the f i e l d .  1964.  and s u r v i v a l of young  The studies c i t e d have shown that reproductive condition in  the peccary does not occur i n a predictable rhythm stimulated by changes i n photo-period.  seasonal  Rather, being.an animal of t r o p i c a l o r i g i n , i t s  reproduction' i s geared to other environmental circumstances.  The nature of  2. these proximal stimuli were not known.  I t i s known that this species in  Texas and Arizona produced young at any time of the year though there was indication of a seasonal concentration i n the l a t e spring.  Sows were known  to be capable of producing two l i t t e r s per year i n c a p t i v i t y (Sowls, 1961a). More young at foot had been noted during periods following substantial r a i n f a l l than during droughts.  I t has been strongly inferred therefore, that  vegetation i s the proximate factor important to peccary populations in Texas that are ultimately controlled by r a i n f a l l . R a i n f a l l i n Texas i s highly e r r a t i c i n d i s t r i b u t i o n and amount, and the  number of years i n which i t i s less than average exceeds that i n  which i t i s average or greater (Texas Agric. Ext. Serv., 1954).  Thus the  water resource on which plant growth depends fluctuates widely. Numerous studies in Texas have shown that plant growth decreases severely during drought.  Wallmo (1957) showed that on the Black Gap Wild-  l i f e Management Area even the most drought resistant species were severely damaged by drought.  On the Welder W i l d l i f e Refuge the important forage  species of bunch-grasses have been known to suffer up to 77% mortality (Chamrad and Box, 1965).  Thus the plant resource f o r support of herbivorous  mammals fluctuates widely. The effect of r a i n f a l l on some animal populations i s marked. White-tailed deer on the Welder Refuge increased from 1145 deer, at the end of a drought (Knowlton, 1964), to 1600  (130 deer/sq mile) after 2 1/2 years  of high r a i n f a l l and good range conditions (White, 1966), and decreased to 1150 (90 deer/sq mile) during a subsequent severe drought (Low,  1967).  S i m i l a r l y , Marburger and Thomas (1965) found that deer herds i n central Texas can decrease as much as 44/o during drought. c  on the Welder Refuge was also affected.  Reproduction of wild turkeys  Watts (1969) found that nesting  by yearlings did not occur and many adults did not produce youngi during a year.of severe drought. Thus, droughts have a measurable impact on vegetation and through i t on entire animal populations. For vegetation, the effect i s direct, through i n s u f f i c i e n t moisture f o r plant growth and maintenance.  The  influence upon animals i s primarily i n d i r e c t , through limited forage and habitat a v a i l a b i l i t y , and to a minor extent direct, through decreased a v a i l a b i l i t y of drinking water. The purpose of my research was to examine reproduction in the c o l l a r e d peccary (Dicotyles tajacu anguiatus (Cope )) (Woodburne, 1968), l i v i n g i n semi-desert conditions, and to assess the influence of r a i n f a l l on i t s reproduction and productivity.  3.  In order to assess the impact of c l i m a t i c conditions on  peccary  reproduction i t was d e s i r a b l e to compare populations l i v i n g under r e l a t i v e l y "optimum" conditions with those l i v i n g under harsh c o n d i t i o n s .  Southern  Texas was chosen as the l o c a t i o n f o r study of peccaries i n an "optimum" habitat because of r e l a t i v e l y high peccary populations and s u i t a b l e facilities.  The western part of Texas i s generally harsher i n most  regards - - l e s s r a i n f a l l , colder winters, hotter summers, higher evapo r a t i o n r a t e s , l e s s vegetation — - than i s south Texas, and two s i t e s were chosen there f o r comparative study of peccaries.  By chance, c l i m a t i c  conditions during the study made i t p o s s i b l e to compare reproductive performance i n the "optimum" south Texas area under both moist and dry c l i m a t i c conditions and t h i s became the major comparison of the study. So that the populations of peccaries being studied i n the f i e l d could be put i n t o the proper perspective, they were compared with animals r a i s e d on unlimited food i n c a p t i v i t y . I have not been concerned with s o c i a l or other p o s s i b l e i n t r i n s i c mechanisms of population r e g u l a t i o n . The p r o b a b i l i t y of a long sequence of favourable years that would enable the population to reach d e n s i t i e s at which such mechanisms would be l i k e l y to operate appeared to be s l i g h t .  2.  STUDY AREAS My study was concentrated i n south Texas on an area assumed to  represent the optimum of Texas h a b i t a t f o r the species.  The major part  of the study was conducted on the Santa Gertrudis D i v i s i o n of the King Ranch.  A second area, the Rob and Bessie Welder W i l d l i f e  Refuge, served as headquarters  Foundation  and provided supplementary f i e l d data.  This second area i s a region of discontinuous peccarry h a b i t a t but has a r e l a t i v e l y high density of peccaries on s u i t a b l e s i t e s . I selected two s i t e s i n a r i d west Texas where data on r e production of peccaries l i v i n g i n a harsher environment could be obtained f o r comparison with the south Texas data.  These were the Watson Ranch and  the Black Gap W i l d l i f e Management Area. 2.1.  Physiography Figure 1 shows the approximate l o c a t i o n of the four study areas  i n Texas.  The 203,000 acre Santa Gertrudis D i v i s i o n of the King Ranch  i n south Texas i s centered around l a t i t u d e 27° 27'N 02'W,  and longitude 98°  j u s t west of K i n g s v i l l e i n Kleberg, Jim Wells and Brooks Counties.  The ranch i s bounded by sorghum, cotton, and watermelon f i e l d s and ranchlands.  The 7,800 acre Rob and Bessie Welder W i l d l i f e Foundation Refuge  i s about 50 miles NNE of the King Ranch. 28° 07'N  and longitude 97° 22'W,  San P a t r i c i o County,  I t i s centered at l a t i t u d e  and i s seven miles north of Sinton i n  The Refuge i s bounded on the north and east by the  Aransas River and on the remainder by l a r g e c a t t l e ranches.  Both of the  areas are close to the Gulf of Mexico, approximately t h i r t y and s i x miles d i s t a n t , r e s p e c t i v e l y . The south Texas areas are both i n the Gulf Coastal p l a i n s region p r i m a r i l y a r o l l i n g to f l a t homocline c o n s i s t i n g of nearly p a r a l l e l s t r a t a sloping gently to the Gulf of Mexico (Johnston, 1955; Thomas,  1962)  The maximum r e l i e f i n both areas i s about 30 feet with the-base e l e v a t i o n varying from j u s t above sea l e v e l to 150 f e e t .  The s o i l s i n the area are  calcareous sands and clays underlain by moderately indurate c a l i c h e at depths of two to 12 feet (Johnston, 1955; Oakes, et a l . , 1958; Kovar,  1963  Box, 1961). Drainage of the Coastal Bend areas i s e f f e c t e d by numerous small frequently temporary creeks which have carved s i z e a b l e v a l l e y s .  However,  surface drainage on the blackland clays and exposed formations i s very slow due to s o i l texture and lack of gradient, and occasional small pothol  50  40  Black Gap ^ I c U i f / Management  6  Figure 1. Location of the study areas, and r a i n f a l l and evaporation d i s t r i b u t i o n in Texas. = R a i n f a l l (inches) = Evaporation (inches x = Station record, evaporation rainfall Mod. from Bloodgood, et a l . , 1954, and Thomas, 1962.  Rob and Bessie Welder W i l d l i f e Foundation Refuge. Santa Gertrudis Division, King Ranch.  TE X A S 0  50  CJl 100  6. remain f o r considerable periods.  Windmills, water tanks and earthen  are scattered over the areas at approximately  1 1/2 mile i n t e r v a l s .  The two a r i d s i t e s are both in west Texas ( F i g . 1). acre Ralph Watson Ranch i s centered at 30° 21'N  The 13,120  l a t i t u d e and 101°  longitude i n the Edwards Plateau region (Thomas,1962). 15 miles east of the Pecos River and 25 miles SSW County, and i s surrounded  tanks  25'W  I t i s approximately  of Ozena i n Crockett  by other large sheep ranches.  The  approximately  100,000 acre Black Gap W i l d l i f e Management Area i s centered at 29° 32' N l a t i t u d e 102° 54' W longitude in Brewster County i n the Big Bend area of Trans-Pecos Texas (Thomas, 1962).  Its SE boundary i s the Rio Grande and;  the SW boundary i s the Big Bend National Park.  :  Several large c a t t l e  ranches  are on the northern boundary. On the Watson Ranch the o r i g i n a l plateau i s about 2200 feet above sea l e v e l ,  and wind and rain have carved extensive valleys and canyons down  to a base elevation of 2000 f t . The s o i l s are calcareous stony and clay loams underlain by caliche (Carter and Cory, 1932;  Oakes, et a l . , 1958).  Drainage i s very rapid i n the area, and streams seldom contain water except after r a i n f a l l .  Windmills, water troughs and overflow ponds are located  around the ranch f o r watering livestock. The Black Gap;Wildlife Management Area i s exceedingly broken, with barren, rocky mountains and plateaus to 5600 feet surrounding f l a t basins and plains down to 1700 feet.  The s o i l s are calcareous clay loams and sands  derived from limestone and igneous parent material (Wallmo, 1957; a l . , 1958).  Oakes, et  The Rio Grande i s the only permanent stream i n the area, and  drainage i s very rapid over the remainder of the area.  Water tanks and catch-  ment basins are scattered over the area to provide water f o r w i l d l i f e . The s o i l s i n a l l of the study areas are generally very f e r t i l e and require only water to support luxuriant vegetation.  The west Texas s o i l s con-  tain much less clay and have a lower moisture holding capacity.  No nutrients  and known to be lacking i n the s o i l s over most of the area (Bray, 1901). 2.2.  Climate The climatic elements important to peccaries are those that con-  t r o l the growth and the persistence of the food resources and those a f f e c t ing peccaries d i r e c t l y .  Thus, r a i n f a l l , evaporation rate, temperature and  s o i l moisture are important.  R a i n f a l l varies markedly i n d i s t r i b u t i o n and  amount from year to year i n Texas and variations i n temperature, and s o i l moisture are largely dependent on the r a i n f a l l .  evaporation,  Therefore, r a i n f a l l  i s probably the single most important factor in the environment as i t affects peccaries through the influence of vegetation.  Because i t was more  p r a c t i c a l to obtain data on r a i n f a l l than on vegetative c o n d i t i o n s , I concentrated on that aspect rather than on range p r o d u c t i v i t y studies. The climate of south Texas i s semi-arid and megathermal, whereas the western areas range from semi-arid to a r i d and are mesothermal thwaite, 1948).  (Thorn-  Average temperatures are only s l i g h t l y warmer, but minimum  temperatures are considerably higher i n south Texas (Table 1.). f l u c t u a t i o n s i n the west Texas s i t e s are more extreme.  The d a i l y  Table 1 shows the  average maximum temperature i n J u l y and the average minimum January temperature i n the two study regions.  F i g . 2 shows the monthly average,  minimum, and maximum temperatures f o r the four study s i t e s during the study period.  It.-.should be noted that the winter of 1966-67 was colder  than the previous two years i n south Texas. Table 1.  C l i m a t o l o g i c a l c h a r a c t e r i s t i c s of the four study areas. (Data from Belo Corp., 1965; Bloodgood, et^ a l . , 1954; King Ranch Inc., unpubl.)  _Aug J u l y max (°F) Aug Jan min (°F) Period of Frost (Days) Mean Annual pptn (inch) Mean Annual Evaporation (inch) Pptn/Evap. ratio Humidity Avg  South Texas JCing Ranch Welder Refuge  West Texas Black Gap Area Watson Ranch  96  94  95  100  48 Decc 16-Feb 5  47 Dec 14-Feb 14 (62)  38 Nov 14-Mar 26 (132)  32 Nov 9-Mar 31 (142)  30.60  14.90  11.35  (51) 26.50 97 (Laredo) 3:1  57.34 ( B e e v i l l e ) 84 2:1  65-90  65-90  (Beeville)  (Dryden)  99.80  5:1  9:1  48-54  28-50  P r e c i p i t a t i o n throughout Texas i s h i g h l y e r r a t i c i n quantity, d i s t r i b u t i o n , and time.  (Figs. 3 & 4 ) .  (Tex. Agr. Ext. S erv., 1954).  Droughts occur about 1/3 of the time  Generally, rains are heaviest i n the spring  and e a r l y f a l l i n south Texas, and i n the summer i n west Texas.  The south  Texas areas receive about twice as much r a i n as the west Texas areas (Table 1, F i g . 1 ) , consequently vegetation production i s considerably higher and peccary d e n s i t i e s there are greater.  1965  1966  1967  F i g . 2. Monthly average, maximum, and minimum t e m p e r a t u r e s f o r the f o u r study a r e a s d u r i n g t h e s t u d y . The p o r t i o n i n b l a c k r e p r e s e n t s f r e e z i n g conditions.  Figure 3. Deviation of monthly r a i n f a l l ( S ) from the long-term monthly average ( d ) on the King Ranch and the Welder Refuge.  10.  BLACK  ~  z  GAP  4-  <  te.  Figure 4. Deviation of the monthly r a i n f a l l ( Q ) from the long-term monthly average [{~} ) near the Watson Ranch and the Black Gap Management areas.  11. A d e f i n i t i o n of drought appears appropriate.  Drought i s a  complex concept and i s d i f f i c u l t to measure objectively.  The only  d e f i n i t i o n that i s generally accepted i s that i t i s a severe shortage of water.  (Gibbs and-Wlaher,1967).  The determination of "shortage" requires  d e f i n i t i o n r e l a t i v e to the object of i n t e r e s t .  In r e l a t i o n to plants, i t  occurs when there i s i n s u f f i c i e n t water present i n the s o i l to enable plant growth to take place (Carrodus, 1967).  In r e l a t i o n to herbivores,  i t occurs when water i s so d e f f i c i e n t as to r e s u l t i n a shortage of forage (R.A. Perry, pers. comm.).  Generally speaking, the biota i s  generally adapted to a r a i n f a l l l e v e l near normal, consequently, s i g n i f i c a n t departures from normal can seriously influence the biota. Several methods of measuring drought have been used.  In Texas  i t i s .generally "accepted that when.the annual r a i n f a l l i s less than 70% f  of the mean annual r a i n f a l l , a drought situation exists'(Texas Agric. Extension Serv.,1954).  Several authors have stated that the amount of  r a i n f a l l i s the best single indicator of drought (Gibbs and Maher,1967; Slatyer,1962).  A better indicator of degree of drought i s an index  using r a i n f a l l and evaporation, although such measurements have no biol o g i c a l component.  Newsome (1966a) has proposed one method of objectively  determining the severity of drought by using evaporation, r a i n f a l l , and the amount of r a i n f a l l that e f f e c t i v e l y causes a response of vegetation as determined by Slatyer (1962:121) f o r central Australia. I have used a s i m i l a r measure to determine the degree of a r i d i t y . Although central Australia receives an average r a i n f a l l about 1/3 that of south Texas, the amount of r a i n f a l l required to i n i t i a t e growth i n plants i s probably s i m i l a r .  My limited observations of plant growth a f t e r r a i n f a l l  in south Texas indicate.this i s not an unreasonable assumption.  In  calculating an aridity^index, the e f f e c t i v e r a i n f a l l required to i n i t i a t e plant growth during the hottest 6 months (Miay-Sept.) was assumed to be 1 inch.  During the coolest 6 months (Oct.-Mar.') i t was assumed to be  0.5 inch.  The a r i d i t y index was determined by subtracting the average  d a i l y open-pan evaporation from the daily r a i n f a l l .  When r a i n f a l l s u f f i c i e n t  to i n i t i a t e plant growth occurred, the index was reset to that amount on the positive side i f the index had been negative, and added to the index i f i t had been p o s i t i v e . next r a i n f a l l .  Subtraction of daily evaporation continued u n t i l the  I f the r a i n f a l l was i n s u f f i c i e n t to i n i t i a t e plant growth,  the amount of rain was added to the a r i d i t y index. accumulated  The graph of the  rainfall-evaporation data i s shown i n F i g . 5.  Also plotted on  the graph are the approximate periods favourable to plant growth, March to  F i g . 5. A. B.  A r i d i t y index f o r the Welder Refuge (south Texas). A r i d i t y compiled using d a i l y r a i n f a l l records. Monthly summary o f a r i d i t y using monthly t o t a l s . Sur.= surplus moisture; Mo.Ave. = average monthly r a i n f a l l f o r 10 years at Welder Refuge; Dr. =.drought, r a i n f a l l d e f f i c i e n t or near d e f f i c i e n t f o r plant growth.  [TTT1=  ]=  major plant growth periods  secondary plant growth periods  14. June and mid-September to October. During the study period, s l i g h t drought conditions prevailed through 1964 to May, 1965 i n south Texas, but good rains i n February, 1965 provided s u f f i c i e n t s o i l moisture to i n i t i a t e and sustain spring plant growth u n t i l the May rains broke the drought (Fig. 5).  Precipitation,  on both the King Ranch and Welder Refuge, was above average f o r the l a s t half of 1965 and Spring of 1966 (Figs. 3 and 5), and plant growth was luxuriant over the winter.  Drought conditions started again i n mid-1966,  and became extreme by September, 1967 (Orton, 1967) when they broke with hurricaneBeulah.  Growth of vegetation was very poor during the normal  autumn and spring growing periods i n 1966 -67. In west Texas p r e c i p i t a t i o n was below average i n 1965 and above average i n 1966 (Fig. 4) and range conditions reflected the differences. 2.3. Vegetation Thomas (1962) and Gould (1962) have summarized conditions i n Texas and l i s t e d the plants.  ecological  In general, the vegetation i n  south Texas i s much denser than i n the more a r i d west Texas areas ( f r o n t i s piece and Plate l ) . The Welder Refuge l i e s i n a t r a n s i t i o n a l area between the South Texas Plains and the Gulf P r a i r i e s and Marshes of Thomas (1962) and i s i n Dice's (1943) Tamaulipan B i o t i c Province.  A l i s t of s c i e n t i f i c names of  plants i s given i n Appendix A, and the s c i e n t i f i c names are used i n the text only where necessary to avoid confusion. Peccaries were mast commonly observed on the clay loam and sandy loam s i t e s and not infrequently on the bottomland s i t e s .  The clay loam s i t e s  support c h a p a r r a l - b r i s t l e grass, p r i c k l y pear-shortgrass and huisachebuffalograss communities.  On the sandy loam s o i l s , huisache—bunchgrass,  colubrina-bunchgrass, chittimwood-hackberry, and l i v e oak-chaparral communities were frequented by peccaries.  Both communities of the bottomlands,  hackberry-anacua and the woodland-spiny aster complex, were used frequently f o r cover and feeding.  The plant communities of the Welder Refuge have been  described i n d e t a i l (Box, 1960,1961; Box and Chamrad, 1966). The King Ranch l i e s primarily i n the south Texas Plains and partly in the Gulf P r a i r i e s and Marsh Vegetational Areas (Thomas, 1962) and i n Dice's (1943) Tamaulipan B i o t i c Province.  The Santa Gertrudis Division i s  included i n Tharp's (1939) Mesquite-Chaparral Region except f o r the s t r i p of  15.  Plate 1.  Representative peccary habitat i n south Texas and west Texas. a.  One-year o l d root-plowed chaparral-prickly pear community on the King Ranch i n south Texas. Note the mature mesquite brush row on the horizon, and sparse huisache, and grassy areas i n the foreground. The p r i c k l y pear i n the center i s 2 to 3 feet high. Peccaries feed out into the root-plowed areas and shelter i n the brush rows.  b.  Several-year old root—plowed chaparral—prickly pear community on the King Ranch. Note the height and density of the mesquite, huisache, and granjueno bushes. The p r i c k l y pear i s 3 to 4 feet high.  c.  A densely vegetated community of the lowland desert scrub association on the Black Gap W i l d l i f e Management Area i h west Texas. Note the lechuguilla, chinograss, and whitethorn, and the extensive bare areas. The l e c h u g u i l l a i s an important food source f o r peccaries i n west Texas.  17. sandy s o i l stretching across the southern t i p of the Division which i s i n the ecatone between Coastal Mainland Dunes Region and the Mesquite-Chaparral Region. Johnston  (1955) discusses the vegetation and the edaphic and c l i -  matic factors involved i n the areas.  The communities of the King Ranch are  s i m i l a r to those of the Welder Refuge, but the chaparral-bristlegrass community i s more extensive over most of the Santa Gertrudis Division. sandy south end of the Division the p r a i r i e bunchgrass—annual replaces the chaparral.  In the  forb community  Nopal p r i c k l y pear (Opuntia lindheimeri) i s f a r  more common over most of the Division than i t i s at the Refuge.  Peccaries  were most numerous i n the p r i c k l y pear dominated brush communities. The dominant species i n the brush community i s honey mesquite,  vary-  ing i n height from shrub to tree form.  Several acacias, blackbrush, huisache,  twisted acacia, p r i c k l y ash, granjueno,  agarito, lotebush and sapote are also  quite common i n the brushy areas.  P r i c k l y pear cactus and t a s a j i l l o , or jump-  ing cactus, are widely distributed and common i n the brush.' Forbs and grasses are sparsely, but widely, distributed i n the deep brush communities, but become the dominant forms i n the p r a i r i e areas s c a t t e r ed through the brush and on the loose sandy areas at the south end of the Division.  Seasonal aspects are evident i n the forbs.  hairy tubetongue,dwarf  Among the species are  ayenia, iceweed and l y r e - l e a f parthenium.  Grasses are  very numerous; 218 species are recorded f o r the Coastal Bend region with Andro— pogon, Panicum, Paspalum, Eragrostris, and Stipa being the major genera  (Gould  and Box, 1965). Distribution of the chaparral on the King Ranch has been extensively changed by brush control practices.  Through the use of a 'rootplowing' tech-  nique (Box and Powell, 1965), large areas are cleared of brush with the usual r e s u l t that p r i c k l y pear i s widely scattered, and roots quickly. dominant species and provides emergency food f o r livestock. also establish quickly.  I t becomes a  Grasses and forbs  Brush s t r i p s are l e f t at about 1 1/2 mile i n t e r v a l s  and along creek beds, roads, and fences to prevent erosion and to provide shade and cover f o r livestock and w i l d l i f e .  The intervening areas are rootplowed  every 12 to 15 years when the brush has replaced the cactus and herbaceous plants (Mr. Wilkinson, pers. comm.). p r i c k l y pear-bunchgrass  The o v e r a l l pattern i s one of blocks of  communities ( i n varying proportions of each) i n various  successional stages of brush invasion separated from each other by s t r i p s of mesquite-chaparral (Plate l a and b) .  1 8 .  The Watson Ranch i s located i n the Edwards Plateau vegetational area of Thomas  ( 1 9 6 2 ) .  Tharp  ( 1 9 3 9 )  divided the Edwards Plateau into four  vegetational regions, and described several plant communities i n the area of the ranch (.Tharp, exists.  1 9 4 4 ) .  On the mesa tops, a sotol-bunchgrass community  In the canyons and valleys are scrub forests,  chapparal-bunchgrass,  and occasional l i v e oak-hackberry mottes, with extensive open areas of bunchgrasses and forbs.  Bare s o i l and rocks are much more extensive than  in the south Texas areas. P r i c k l y pear (Opuntia lindheimeri and 0 . engelmannii), sotol, and l e c h u g u i l l a are scattered throughout the area and forbs are p l e n t i f u l following r a i n s . The Black Gap Management Area i s located i n the highly variable Trans-Pecos vegetation area of Thomas  ( 1 9 6 2 ) .  Wallmo  ( 1 9 5 7 )  recognized two  major groups of vegetation types i n the Big Bend, the Lowland Desert Scrub Associations and the Mountain Bush and Woodland Associations. In the lowland areas with l i t t l e v e r t i c a l variation and no abrupt changes i n a l t i t u d e , the whitethorn-creosote bush-lechuguilla community dominates.  Creosote bush i s the dominant plant with l e c h u g u i l l a , whitethorn,  p r i c k l y pear ( p r i n c i p a l l y Opuntia engelmannii) t a s a j i l l o , o c o t i l l o and sotol (Dasylirion leiophyllum) more or l e s s densely scattered throughout. ( 1 9 5 7 )  found the "ground vegetation" covered an average of only  "canopy"  18.3°/o  10.5°/o  Wallmo and the  of the t o t a l plot area.  On the upland s i t e s and lowland areas where moisture conditions are more favorable ( i n draws, at edges of rock caps, etc.), the more densely vegetated sotol-lechuguilla-chinograss communities dominate. Sotol, yuccas, chaparral, species such as whitethorn, mesquite, blackbrush, catclaw, g u a j i l l o , o c o t i l l o , creosote bush, tarbush, several junipers, and p r i c k l y pear are the predominant "canopy" plants.  Chinograss, sand bur  (Cenchrus myosuroides), lupins, lechuguilla, goldeneye, croton (Croton neomexicanus), and others make up the ground vegetation. 2.4.  Competitors and predators Blair  ( 1 9 5 0 )  l i s t s the animals c h a r a c t e r i s t i c of each of Dice's  b i o t i c provinces i n which the study areas are situated.  ( 1 9 4 3 )  The s c i e n t i f i c names of  the mammals c i t e d are given i n appendix A. Mammalian herbivores important to the south Texas area are c a t t l e , deer, c o t t o n t a i l s , jackrabbits, and a variety of rodents, notably the cotton rat and the southern plains woodrat.  On the Refuge there are 4 0 0 tp 5 0 0 steers?  19. about 40 animals/sq mile, while on the King Ranch, the density i s a l i t t l e greater.  Whitetailed deer populations here are second i n density only to  the Central Mineral Basin of Texas (Teer et a l . , 1965;  White, 1966).  On the  Refuge, the population varied between 1100 and 1600 animals, or from 91.4 to 133.3  deer/sq mile (White, 1966).  On the King Ranch, the population has been  conservatively estimated at 31.5 deer/sq mile ( K i e l , 1963).  A variable number  of f e r a l pigs range over parts of the Welder Refuge, but the density i s usually kept low by constant hunting.  No f e r a l pigs were present on the Santa Gertrudis  Division of the King Ranch despite a r e l a t i v e l y high density on the Laurelos Division a few miles to the east. Important carnivores i n the area are the coyote, bobcat, grey fox, badger, and raccoon.  Coyotes are f a i r l y common on both areas, despite the  fact that populations on the King Ranch are controlled and those on the Refuge are not. 1965,  White (1966) estimated 25 to 40 on the 7,800 acre Welder Refuge i n  and the density i s s i m i l a r or higher on the King Ranch due primarily to  the higher rodent populations l i v i n g i n the more extensive p r i c k l y pear communities.  In 2 1/2 years, 959 coyotes and 158 bobcats were removed from the  King Ranch without apparently a l t e r i n g the density of the two species (King Ranch trapping records, unpubl.). Between 2,000 and 3,000 sheep are kept on the Watson Ranch.  This  i s between 98 and 146 sheep/sq mile, which i s about average f o r the county (Teer et a l . , 1965:19). Several cows and horses are also kept on the ranch. An unknown number of deer range the area, but an estimate f o r an adjacent area places the density at 9.6  deer/sq mile (Teer _et a l . , 1965).  Coyotes, bobcats and mountain l i o n s have been eliminated sheep ranching area, so that predation on peccaries i s v i r t u a l l y  from t h i s  absent.  Livestock were removed from most of the Black Gap area i n the early 1950's, and only along the Rio Grande valley bottomlands do horses and goats trespass.  Mule deer have been extensively studied on the area and densities  of 11.0 to 16.4 deer /sq mile were estimated from p e l l e t groups (Wallmo, 1959). During the two years that I collected data on the area, the population estimate increased from 22.1 Approximately  to 22.7  deer/sq mile (Hailey, 1966;  Brownlee, 1.967).  100 pronghorn antelope range over the northern and western por-  tions of the area.  Jack rabbits, c o t t o n t a i l s and numerous rodent species are  present. Coyotes, bobcats and mountain l i o n s are not generally controlled on the Black Gap area, but densities are not high. present i n varying number.  Grey fox and badgers are also  20. 3.  METHODS and MATERIALS The methods employed i n the study were designed to obtain data on  the e f f e c t of climate and c l i m a t i c changes on reproduction and p r o d u c t i v i t y of peccaries.  The i n i t i a l approach was to compare reproductive performance  of animals under a presumed optimum regime i n south Texas and under a harsher c l i m a t i c regime i n west Texas.  By chance, circumstances during the study  made i t p o s s i b l e to compare the population i n the "optimum" south Texas area under both moist and dry c l i m a t i c conditions and t h i s became the major part of the study.  A s e r i e s of animals was r a i s e d i n c a p t i v i t y to provide a  standard against which reproduction i n the n a t u r a l population could be compared. Headquarters - were established at the Welder Refuge with a temporary headquarters  at the King Ranch Santa Gertrudis D i v i s i o n .  From these l o c a t i o n s  frequent t r i p s were made i n t o the f i e l d to observe and c o l l e c t peccaries. A f t e r an exploratory period of three months, J u l y to September, 1964,  collection  of .data i n south Texas began i n February, 1965, and terminated i n August,  1967.  Seven t r i p s were made to the Watson Ranch over the period from November, 1965 to J u l y , 1967, to observe and c o l l e c t peccaries.  Two t r i p s were made to the  Black Gap area to obtain data from h u n t e r — k i l l e d peccaries during the annual hunt i n l a t e November of 1965 and 1966.  An a d d i t i o n a l t r i p was made to the  Black Gap area i n February, 1967, i n an attempt to obtain supplementary data. The primary means of obtaining data on reproductive performance was to c o l l e c t animals at i n t e r v a l s frequent enough to assess the reproductive cond i t i o n of the population. pen—reared  A d d i t i o n a l data on reproduction were obtained from  peccaries and from l i v e — t r a p p e d peccaries.  Data on s u r v i v a l and  recruitment were obtained by observation of both marked and unmarked animals. 3.1.  C o l l e c t e d animals Altogether, 153 peccaries were c o l l e c t e d i n south Texas, during the  period March 1965 to August 1967..  Seven were from the Welder Refuge and  from the Santa Gertrudis D i v i s i o n of the King Ranch.  146  Most of the animals were  k i l l e d with a r i f l e (high.power and .22 c a l i b e r ) , but some were caught by the U.S.  F i s h and W i l d l i f e Service predatory animal trapper i n double spring s t e e l  traps set f o r coyotes and bobcats. l i v e - t r a p accidents and road k i l l s . Ranch with a r i f l e .  Several specimens were obtained from I c o l l e c t e d 17 peccaries on the Watson  Hunters brought 119 peccaries through the check s t a t i o n  on the Black Gap Management Area and from these I obtained reproductive data on 32 females and 48 males.  21 . During the i n i t i a l phase of the study, an attempt was made to sel e c t i v e l y c o l l e c t adult females, but d i f f i c u l t y of rapid sex determination in the f i e l d proved this to be impractical.  From July, 1965, the c o l l e c t i o n s  were more random, but i f sex could be determined readily, females were taken preferentially.  Animals judged to be immature were generally not collected  unless c o l l e c t i o n of a complete herd was  attempted.  The following data and materials were obtained during autopsy of the specimens from south Texas and the Watson Ranch:  date; time; location,  and means of c o l l e c t i o n ; habitat; sex; age; weight and measurements; general condition of pelage and skin abnormalities; ectoparasite and endoparasite loads; blood serum f o r arbovirus assay; weights of body organs; kidney f a t estimate; eye lenses; s k u l l and lower jaw; reproductive state; and a stomach sample taken from the rumen portion of the subruminant  stomach.  From females,  the reproductive t r a c t was weighed entire; the number, location, sex, weight and crown-rump measurement of foetuses were determined and the foetuses preserved; each ovary weighed and preserved; the mammary gland was weighed and l a c t a t i o n condition noted.  From males, the testes were weighed and one or  both preserved. From animals k i l l e d by hunters on the Black Gap area, body measurements, and carcass weight were taken along with the lower jaw and reproductive t r a c t i f the hunter permitted or brought the parts i n .  On several animals  complete autopsy, as f o r the south Texas specimens, was possible. Twentyfive peccaries which had been pen-reared were also autopsied and the same data as f o r south Texas animals taken. 3.2.  Live-trapping The live-trapping program was carried out during the periods of  September, 1964, and A p r i l , 1965 to July, 1967 on Mesquite Pasture on the King Ranch and on the Welder Refuge.  Most of the peccaries trapped were  caught i n wooden deer traps 4 f t x 4 f t x 8 f t (Glazener, 1949) f i t t e d with a 1 inch x 2 inch mesh wire f l o o r , and a drop gate. used f o r b a i t . immediately.  Cottonseed p e l l e t s were  The t r a p l i n e was usually run early i n the morning and reset Most of the animals were caught i n the early evening.  On the King Ranch, nine traps were operated i n seven locations that were changed twice during the study. one week period once a month.  Usually trapping was conducted over a  However, during the f i r s t year of the study,  the trapping i n t e n s i t y was higher i n an e f f o r t to get a large number of animals marked early i n the study.  During the l a s t ,8 months, trapping was concentrated  22. on the Welder Refuge.  Trapping was i n i t i a t e d on the Welder Refuge i n  January, 1966, and a variable number of traps (up to f i v e ) were operated on an i r r e g u l a r basis u n t i l July, 1967.  Peccaries caught i n double spring  s t e e l traps i n the marked-animal study area were also tagged and released. The method of handling the animals i s treated i n Appendix B. The following data were recorded on the trapped animals:  location,  external c h a r a c t e r i s t i c s , associates, relationships of animals within the traps, and age as adult (old, prime, young),  juvenile (6 to 12 months),  grown (3 to 6 months), and red young (birth to 3 months).  On  1/2  subsequent  recaptures, date,location, and associates were recorded. When f i r s t trapped, the animals were i n d i v i d u a l l y marked with ear tags, and some were f i t t e d with a harness.  An i n d i v i d u a l l y patterned, colored  vinyl-coated nylon streamer (Armor-tite, Cooley, Inc., Pawtucket R.I.) held i n place with a numbered button tag (Knowlton, ear of females and the l e f t ear of males. was placed i n the other ear.  et a l . , 1964) i n the r i g h t  A numbered s e l f - p i e r c i n g strap tag  I n i t i a l l y , a l l adults were also marked with a  harness modified from B i g l e r ' s (1966) design. straps.  was  The modification has two dorsal  Females were marked with a yellow rope harness, and males with a red  rope harness.  It was found to be unsatisfactory:  unless it. was put on very  t i g h t , i t allowed tha animals to s l i p out of the harn ess, and i f i t was very t i g h t , the breast and' shoulder straps cut into the animal.  Three animals  collected 12 to 22 months a f t e r being tagged had the polyethylene rope cutting well into the sternum with bone a t t r i t i o n on the inside and deposition on the outside.  Within a month a captive animal f i t t e d with a harness had developed  a suppurating wound under the dorsal strap and had started to limp. Several animals were f i t t e d with radio transmitter c o l l a r s operating on Citizens Band frequencies. by I n g l i s , _et a l . ,  The equipment was modified from that described  (1968) and Cook _et a l . ,  (1967).  I p e r i o d i c a l l y located  the animals through use of a loop antenna and noted t h e i r location and attempted to determine t h e i r associates and a c t i v i t y . A t o t a l of 171  peccaries were marked, 19 on the Welder Refuge and  162 i n the north end of Mesquite Pasture and adjacent pastures on the King Ranch.  3.3  F i e l d Observations In conjunction with the other f i e l d operations, records were kept  of a l l peccaries observed. age:  adult, 6-12  The animals seen were c l a s s i f i e d as to seX and  months o l d (juvenile), 3-6 months old (1/2 grown), and  0-3  23.  months old (red young) i f possible. was no ted and a c t i v i t y recorded. 3  The time and location of the sighting  Marked animals were i d e n t i f i e d i f possible  and recorded. 3.4.  Pen-reared animals At the University of B r i t i s h Columbia, peccaries were kept i n  i n d i v i d u a l pens 4 f t wide x 8 f t long with walls 4 f t high constructed of cement blocks. the winter.  The pens were housed i n a building that could be heated i n  Free-running water was available at one end of the pen and a  food hopper was placed at the other end.  A concentrated pelleted cereal  ration (UBC 36-57) (Wood, et a l . , 1961) designed f o r deer was fed ad libitum and the amount consumed was measured.  Even though fed ad libitum,  the animals did not become obese, but remained i n good condition,  the young  were l e f t with the sows u n t i l they were weaned at two to three months.  They  had access to the pelleted food as soon as desired. During breeding t r i a l s , the females were taken from t h e i r pens and placed i n the pen of the boar.  This eliminated much of the aggressivness of  the females, and p a r t i c u l a r l y diminished the aggressive response of a.new mother.  The females were allowed to remain i n the pen with the boar f o r 15  to 20 minutes.  As Sowls (1966) has shown, most of the mating took place i n  the f i r s t f i v e minutes i f the female was receptive.  The females were placed  with the males usually two or three times a week, unless the sow was to be pregnant.  thought  Several sows were presented to the boar immediately a f t e r  p a r t u r i t i o n , and daily f o r two weeks before going back to the regular schedule. The animals were weighed at i n t e r v a l s i n keeping with t h e i r growth stage, progressing from weekly f o r very young to monthly f o r adults. Peccaries at the Welder Refuge were maintained i n shaded, chainl i n k wire pens open to the elements. in one large pen. per day per adult. fat.  They were usually allowed to run together  They were fed commercial hog p e l l e t s at a rate of about 2 l b s On t h i s s l i g h t l y r e s t r i c t e d diet they did not get overly  Water was f r e e l y available. The Welder Refuge penned animals were p e r i o d i c a l l y weighed, mea-  sured and tooth progression noted, and on some, dental impressions taken.  3.5.  Age determination Ages of the collected animals were determined by tooth eruption pat-  terns i n animals less than 24 months old, and from annulations i n the cementum  24. of the f i r s t i n c i s o r of animals older than 24 months.  The tooth eruption.pat-  terns were developed from captive animals and the tooth annualtions from peccaries pen-raised i n Arizona, at U.B.C., and the Welder Refuge.  Ages of  trapped animals were determined from tooth patterns and body s i z e .  Ages of  foetuses were determined by comparison with growth patterns of f o e t a l pigs (Ullrey, et a l . , 1965) and deer (Thomas, 1970), and from the formula developed by Hugget and Widdas (1951) where a = .092 and t5 = 38 days.  The development  of the age determination techniques i s shown i n Appendix C.  3.6.  Sex determination Male and female peccaries are morphologically very s i m i l a r .  Males  have s l i g h t l y shorter and more massive rostrum and lower jaw (unpublished data), but these are d i f f i c u l t to detect i n the f i e l d .  Urogenital organs and  behaviour provide a clue to sex of free-ranging animals.  On the male, the  s c r o t a l sac i s devoid of hair and protrudes s l i g h t l y to the rear.  On adults,  the testes make a f a i r l y obvious swelling, but both sexes of young animals appear s i m i l a r .  The preputial opening i s usually surrounded by a t u f t of  hair, but t h i s character also i s not completely r e l i a b l e because  female  occasionally have a t u f t of hair protruding i n the central abdominal area. On females, a distended udder can be detected with some d i f f i c u l t y . Behaviour i s frequently i n d i c a t i v e of sex.  Urination posture of  the females i s c h a r a c t e r i s t i c , and frequently location of the urine on the ground beneath the animal indicates the animal's sex.  Observation of  nursing was also a useful c r i t e r i o n . S o c i a l i t y can also be used with high p r o b a b i l i t y to determine sex. Frequently animals that were by themselves were older boars.  Of 131 obser-  vations of obviously s o l i t a r y animals, 88% of the 67 animals sexed were males.  There i s some bias towards males because i t i s possible to d i s -  tinguish whether the scrotum was present from greater distance than i t was possible to determine  3.7.  absence.  Census During the f i r s t year of the study', a census l i n e was operated i n  conjunction with the trap routes. not appear to be r e a l i s t i c .  This was discontinued as the r e s u l t s did  Population fluctuations may be determined more  accurately by watching fluctuations i n i n d i v i d u a l herds, although Day (1964, 1965,  1966) has found the technique to be unreliable where populations are  hunted.  25. 3.8.  Food habits The stomach contents of 73 peccaries collected on the King Ranch  over the study period were analyzed to determine species composition.  A  sample was taken from the globular central chamber (Moir, 1958) of the three-parted subruminant stomach and preserved i n 1Q°/o Formalin.  The samples  were examined by the procedure outlined by Chamrad and Box (1964) to determine the percent volume of the component species. 3.9.  Growth Growth patterns were established from pen-raised peccaries and  from wild peccaries whose age was determined from tooth eruption or annuli. Pen-raised animals were weighed at weekly i n t e r v a l s u n t i l they reached 2 to 3 months, then biweekly to 4 or 5 months, and monthly a f t e r that. Foetuses were weighed and the crown-rump length taken from forehead to posterior-most part of the rump, with the vertebral column straight, and the head at right angles to the vertebral column.  On some postnatal young,  crown—rump measurements were taken f o r comparison with f o e t a l young. Wild peccaries less than 20 l b s . were weighed to the nearest 1/lOth pound, and animals over 20 l b s . were weighed to the nearest pound.  I f the  animal had been bled, an a r b i t r a r y 5% was added to the weight to obtain a l i v e weight (Prosser and Brown, 1950). Standard body measurements were taken with a f l e x i b l e s t e e l tape. They were:  t o t a l length, hind foot length, and ear length, (from notch)  shoulder height, chest g i r t h , and, on some animals, neck g i r t h . Total length was measured along the dorsal contour while the head was i n a natural position.  Shoulder height was measured from the toe and  followed the contour of the shoulder to the vertebral column (Teer, et a l . , 1965). cut.  Chest g i r t h was measured only on animals whose brisket had not been For t h i s reason, few of the hunter—killed and gutted peccaries were  measured f o r t h i s character. The standard error of the measurements was:  t o t a l length + .19  inch, hind foot length + .05 inch, ear + 0 inch, shoulder contour height + .22 inch, chest g i r t h + .63 inch. Carcass weight i s preferred as a measure of animal weight  because  stomach and uterine contents of l i v e animals cause l i v e weights to vary excessively.  Live weight of adult south Texas peccaries i s related to car-  cass weight according to the regression, y ( l i v e weight) = 1.45x + 1.3, with  26. a highly s i g n i f i c a n t c o r r e l a t i o n c o e f f i c i e n t ( r = .98, d.f. = 67) f o r males, and y = 1,67x  - 2.3  ( r = .94, d.f. = 69) f o r females.  females i s due to v a r i a t i o n caused by pregnancy-related 3.10  The lower ' r ' f o r the weight changes.  Condition I assessed animal condition by estimating the proportion of each  p a i r of kidneys covered by f a t and assigning a Kidney Fat (K.F.) index of G> l/4> 3.11  1/2,  3/4,  1, or between these values.  Male reproduction Testes used i n the a n a l y s i s were obtained from the King Ranch,  Watson Ranch, Black Gap Area, and from pen-reared animals.  A l l testes  except the Black Gap samples were u s u a l l y s t r i p p e d of the tunica and epididymis, weighed, volumes determined, s l i t and preserved i n 10%  Formalin.  The testes from Black Gap specimens were u s u a l l y preserved p r i o r to weighing. I f the testes i n each p a i r were approximately the same s i z e and morphology, only the l e f t t e s t i s was  preserved.  A f t e r preservation f o r varying periods of time, the testes were b l o t t e d dry and weighed to 0.1  gm.  Volumes were determined to 0.1  ml with  a modified manometer. A s e r i e s of 41 testes representing various growth stages of testes of young peccaries, and normal and extremely low weights of adult testes c o l l e c t e d through the year were randomly selected f o r d e t a i l e d h i s t o l o g i c a l examination.  One abnormal p a i r of testes.was also examined h i s t o l o g i c a l l y .  Several authors (Parkes, 1965;  Simard, 1964)  have shown that a  cross-section of the t e s t e s from almost any area i s representative of the whole.  To a s c e r t a i n t h i s , I.examined cross-sections from three areas evenly  spaced along the long a x i s of several t e s t e s .  On the remainder of the selected  t e s t e s , a cross-section from only the mid-portion l o g i c a l l y examined.  The f o r m a l i n - f i x e d sections were p o s t - f i x e d i n Bouin's  s o l u t i o n , embedded i n wax and two or three B p microtome and mounted f o r s t a i n i n g . (1967).  of the organ was h i s t o -  sections cut on a rotary  S t a i n i n g procedures followed Humason  A modified Masson's Trichrome s t a i n , (Weigert's Haematoxylin, Acid  Fuchsin - - Ponceau 2R, A n i l i n e Blue - - Orange G) was used f o r general s t a i n i n g (Humason, 1967).  Some sections were stained with P e r i o d i c - A c i d -  S c h i f f Reagent (Humason, 1967) could be more e a s i l y counted.  i n order that the P.A.S. p o s i t i v e spermatozoa  27. T e s t i c u l a r anatomy and i n f e r r e d physiology were compared using t e s t i s s i z e , seminiferous tubule diameter, spermatogenic a c t i v i t y , spermiogenic a c t i v i t y , and proportion of t e s t i s composed of seminiferous  tubules  and i n t e r s t i t i u m . T e s t i s s i z e was standardized against hind foot length to remove seasonal and age v a r i a t i o n .  (Hind l e g reaches adult s i z e at about 1 year:  Appendix D) . The formula f o r determining the index of testes s i z e i s : . . , /--r-r-i mean of paired t e s t i s weights . , , . T e s t i s Index [TI = , .—\, „ , -, rr, . A monthly reproductive hind foot length ^ index was c a l c u l a t e d by taking a l l c o l l e c t e d males 2 years and over T  fi  T  1  7  (sexually and p h y s i c a l l y mature) and averaging the i n d i c e s . Growth of t e s tes from immature to mature stages was determined by averaging the i n d i c e s of a l l animals i n the same age groups. Diameter of the seminiferous tubules was determined by taking the mean of f i v e cross-sectioned tubules randomly selected from a sub-peripheral area at r e l a t i v e l y equal i n t e r v a l s around the periphery of the t e s t i s . I assessed spermatogenic a c t i v i t y by microscopic examination of several f i e l d s of a t e s t i s cross-section at s u i t a b l e magnification, and c l a s s i f i e d the spermatocytes and spermatids as numerous, moderate or few. Sperm were counted i n the f i v e previously selected cross-sectioned tubules, at 1250 X magnification ( o i l immersion).  The proportion of the t e s t i s com-  posed of tubules was determined with an ocular microscopic g r i d of 20 squares to a side oriented over the t e s t i s s e c t i o n at s u f f i c i e n t magnification to allow the g r i d to f i t j u s t i n s i d e the t e s t i s c r o s s - s e c t i o n .  Five rows of  20 squares were then examined, and the squares c l a s s i f i e d as the material (tubule or i n t e r s t i t i u m ) making up the greatest proportion of the square. The number of squares out of the 100 t o t a l gave the percent of the testes that were tubules, and the complement of that was assumed to be the i n t e r s t i t i u m ( i n c l u d i n g secretory c e l l s , connective t i s s u e , blood v e s s e l s , sec r e t i o n sinuses, e t c . ) . 3.12  Female reproduction Data on reproduction were obtained from females c o l l e c t e d i n south  and west Texas, and from pen-reared animals.  The i n d i v i d u a l l y numbered  ovaries were preserved i n Bouin's s o l u t i o n (Humason, 1967) f o r subsequent analysis.  A representative s e l e c t i o n of the various stages of development  of the uterus were preserved i n 10% Formalin.  The mammary gland was cut  open to determine the s t a t e of l a c t a t i o n , and then discarded.  I f the sow  28. was pregnant, the foetuses were weighed, crown-rump measurements taken, and then preserved i n 10°/o Formalin. From the Black Gap specimens, generally only the ovaries were obtained.  These were preserved i n Bouin's s o l u t i o n as soon as they were  obtained, but they could have been c o l l e c t e d by the hunters up to 36 hours before preservation.  Some reproductive t r a c t s were examined, and  several preserved i n 10°/o Formalin.  No foetuses were brought i n by the  hunters, although two pregnant sows were reported i n 1966. A t o t a l of 73 p a i r s of ovaries were c o l l e c t e d from south Texas specimens, 8 p a i r from Watson Ranch specimens, 17 p a i r from Black Gap specimens, and 9 p a i r from pen-reared specimens with documented reproductive history. A f t e r storage i n Bouin's s o l u t i o n f o r up to 3 years, the ovaries were reweighed to 0.1 gm, volume determined with a modified manometer to 0.1 cc, and measurement taken of the external dimensions of the ovary and protruding corpora l u t e a .  Bouin's s o l u t i o n was removed with several baths  of 70/o ethanol p r i o r to embedding i n wax. c  Embedding the large ovaries  with l a r g e corpora l u t e a proved d i f f i c u l t u n t i l I found that a s c a l p e l cut to the heart of each corpus f a c i l i t a t e d penetration of the c l e a r i n g agent and wax.  The ovaries were double embedded by c l e a r i n g f o r up to 4  days i n methyl benzoate u n t i l the o v a r i e s became translucent.  They were  then t r a n s f e r r e d to benzene f o r 1/2 hour and embedded i n three changes of Paraplast according to standard technique (Humason, 1967). S e r i a l sections of the ovaries were taken on a rotary microtome at 8 JJ and every 12th section mounted consecutively on l a b e l l e d , albumenized glass s l i d e s .  Most of the ovaries from pen-reared peccaries were sectioned  at 8 JJ and every 10th section mounted.  Thus, i n the f i r s t case, one section  from every 96 JJ of ovary was mounted, and i n the second case, one section from every 80 p was mounted.  Because the'oocytes are-.about 120 p diameter,  every oocyte should have been represented on the s l i d e s . The sections were stained i n a modified Masson's trichrome s t a i n (Humason, 1967:166) which included Weigert's haematoxylin, Acid fuchsin  —  Ponceau 2R, and a n i l i n e blue - - Orange G, and covered with Permount and a coverslip. Corpora l u t e a , Graafian f o l l i c l e s , l a r g e r scars, medulla, cysts and the ovary i t s e l f , were measured a t t h e i r l a r g e s t diameters with an ocular g r i d on a binocular d i s s e c t i n g microscope.  The number of sections containing  29. portions of the s t r u c t u r e were counted and m u l t i p l i e d by the appropriate section frequency and thickness to obtain the t h i r d diameter.  The mean  diameter of these s t r u c t u r e s was obtained by adding the three  diameters  and d i v i d i n g by three. formula V = 4/377"^ r  Volume of the s t r u c t u r e s vwas determined from the r ^ where r^ , r^> and r ^ are the three r a d i i .  Shrink-  age of ovaries between c o l l e c t i o n and s l i d e preparations averaged 32.1°/o. The sections were scanned at 25X with the d i s s e c t i n g microscope and scars, f o l l i c l e s greater than 1.5 mm i n any dimension, and cysts counted. A compound l i g h t microscope at appropriate magnifications was used f o r d e t a i l e d examination of s t r u c t u r e s . 3.13.  Statistical  treatment  S t a t i s t i c a l comparisons between sample means were made using Bailey's  (1959:172) method where samples are small, variances are not  assumed equal and sample s i z e s are not the same.  Most graphic comparisons  are made using the mean, 95°/o confidence i n t e r v a l and range unless fewer than four samples are present, i n which case the 95°/o confidence i n t e r v a l i s not shown.  The 95P/ confidence i n t e r v a l i s u s u a l l y abbreviated 0  S.E. t.05  i n the f i g u r e s and t a b l e s as mentioned by S t e e l and T o r r i e (1960:46).  30. 4.  RESULTS  4.1.  Food habits Samples of the stomach contents were obtained from 73 pec-  caries over the 2 1/2 year period from February, 1965 to August, 1967. The samples contained an average of 63% p r i c k l y pear, 18% grass species, 7% forbs and small amounts of animal matter and unidentified plant f i b e r . On. a seasonal basis over the study, the composition varied markedly Throughout  (Fig.6).  the year p r i c k l y pear made up the greatest portion of the diet,  but during the l a t e spring and summer, when they were available, the flowers and f r u i t were taken i n preference to the cladophylls.  Grasses  made up 25% of the diet during the spring, 14% during the summer, and 10% during the f a l l .  Forbs were taken i n preference to other plants as soon  as they became available, and because of the seasonal progression i n forb species, the t o t a l proportion i n the diet changed l i t t l e . Variation i n food a v a i l a b i l i t y associated with p r e c i p i t a t i o n was also present.  In 1965, spring rains followed a two year drought, and  resulted i n an i n i t i a l profusion of annual forbs.  Perennial grasses were  slower i n following, but a f t e r a year of good rains, grasses had increased in abundance.  The hot summer i n 1966 caused browning o f f of a l l herbaceous  material, despite modest amounts of rain, but the cooler autumn conditions enabled some forbs to grow. vented forage growth. of  The drought over the winter e f f e c t i v e l y pre-  However, perennial grasses were able to take advantage  the below average rains that did come during the spring, 1967, and  i n i t i a t e d spring growth.  Lack of rain prevented continued development.  Forbs were very scarce during the spring. These differences i n abundance of the forage classes were r e f l e c t e d by peccary food habits.  P r i c k l y pear cladophylls were constantly available,  and when l i t t l e other food was available, p r i c k l y pear became the dietary staple.  This situation occurred during the f a l l and winter of the 1966-67  drought ( F i g . 6 ) . 4.2.  Condition The kidney f a t index (K.F.) was the most consistent indicator of  general n u t r i t i v e condition.  A K.F. index of less than 1/8 was associated  with very l i t t l e body or mesenteric f a t . Very few animals ever had a K.F. index over 3/4.  Figure 6. Forage c l a s s composition of the stomach contents of 73 c o l l a r e d peccaries from south Texas. Spring includes the period February to May, summer includes June to Ausgust, and f a l l includes September to November.  ^  %  VOLUME  100  -Animal  SUM  MOIST  DROUGHT  matter  33. The animals pen-raised at U.B.C. had up to 3/4 inch of rump f a t on them, yet  had K.F. indices between 1/2 and 3/4.  Juveniles usually had a low  K.F. index between 0 and 1/8 unless they were i n a season of exceptionally good food quality and quantity, as i n the summer and f a l l of 1965. New born animals usually had a K.F. index between 1/4 and 1/2.  There was no  s i g n i f i c a n t difference between K.F. indices of males and females, although females i n the l a s t half of gestation tended to have a s l i g h t l y higher index. The amount of f a t present on the kidneys showed'a d i s t i n c t seasonal pattern ( F i g . 7). During l a t e winter and early summer, the K.F. indices were low.  Adults put on some f a t stores during the spring vegetation growth  period, but the major f a t deposition occurred i n l a t e summer and autumn when most crops were at t h e i r peak. The kidney f a t index appeared to follow the same general seasonal pattern i n west and south Texas, but samples through the year i n west Texas were too small f o r meaningful  comparison.  It i s evident from F i g . 7 that the period of good conditions i n south Texas beginning i n the spring of 1965 resulted i n greater f a t deposi t i o n (up to a K.F. index of 3/4 i n two instances and 1.0 i n one instance) that kept the K.F. index high through the summer and into winter.  However,  during the drought that started i n mid—1966 the animals did not put on much f a t ; consequently, the K.F. index was much lower during the summer and f a l l of 1966 than during 1965. There was l i t t l e difference i n the K.F. index i n l a t e winter of both years. Peccaries collected on the Black Gap area i n 1965 near the end of a minor drought had a s l i g h t l y lower K.F. index than did those collected i n 1966 a f t e r a year of good r a i n f a l l .  This was more evident i n the females,  who went from a mean K.F. index of .18 i n 1965 to .28 i n 1966, than i t was in the males, who went from .23 i n 1965 to .26 i n 1966.  (Fractions were  transposed to decimal figures to f a c i l i t a t e comparison.  I t should not be  inferred that accuracy i s precise to two decimal points.) Animal condition was better during the period of good range conditions i n l a t e 1965 i n south Texas and lower when range conditions were poor i n l a t e 1966, whereas condition was lower i n 1965, and higher i n 1966, in west Texas.  Although sample sizes are smaller during l a t e f a l l i n south  Texas than i n west Texas, the combined September to December sample i s large enough f o r cojftparison.  K.F. indices from south Texas peccaries ranged from  34.  n=  6  5 F  12 M  3  3  1 A  11 M  7  11 J  6  3  8 J  5 A  7  7  1 S  3  4 O  3 N  Figure'7. Seasonal changes i n kidney f a t indices i n south Texas peccaries during moist ( • ) and drought (O) conditions, 1965-67. Values given are mean, 95% confidence i n t e r v a l and the range.  35. 1/4 to 3/4 with a mean of .49 (n = 17), whereas in west Texas the range was 0 to 1/2 with a mean of .20 (n = 59).  In l a t e 1966, the K.F. index  of south Texas peccaries ranged from • to 1/2 with a mean of .21 (n = 6 ) , whereas the west Texas peccaries were i n s l i g h t l y better condition indicated by a mean K.F. index of .26, with a range of • to 3/4 (n = 52).  Thus under  r e l a t i v e l y good r a i n f a l l and range conditions i n west Texas, peccaries there reached a condition s l i g h t l y better than condition of south Texas animals under drought conditions (Table 2 ) .  The south Texas peccaries under good  range conditions almost equalled the condition of pen—reared peccaries (Table 2 ) .  Table 2.  Comparison of F a l l kidney f a t indices of adult captive, south Texas and west Texas peccaries under different moisture, cond i t i o n s . Sample size i s shown i n brackets.  S o u t h Captive  T e x a s  West  Moist  Drought  Moist  .49 (17)  .21 (6)  .26 (52)  T e x a s Dry  Condition  K.F. index  4.3.  .58 (6)  .20 (59)  Growth Weights of three/, known-age foetuses obtained near mid—pregnancy  (105 days) from a captive sow averaged 237 gm (192-279 gm) .  Weights of 15  neonatal peccaries ranged between 570 and 1090 grams, with a mean of 767 gm (1.6 lbs) (Table 3 ) . averaged 525 gms  Eight neonatants that died within a day of b i r t h  (SD = 132), 33°/o l i g h t e r than t h e i r surviving s i b l i n g s . A l l  of the neonatants that died had aerated lungs, so presumably were born a l i v e , but direct-;'cause of death could bot be determined.  Usually the  dead animal was one of twins or t r i p l e t s and the survivors in the l i t t e r s were of average or greater than average weight.  3 6 .  Table 3 .  Weights of neonatal peccaries (pen-raised and wild). No. UBC  391  Sex F  4  "  392  IM  4  F F M F F M F M • M M M M  "  3 9 3  "  394  "  396  "  3 9 5  "  3 9 7  "  4 0 0  "  401  "  4 1 3  "  398  "  3 9 9  P-25  Pecos  M  P-175  Age day "  birth II II II  n  95°/o  SD SE Conf.  Weight (lb-oz)  7 6 6  1  -  11  7 9 5  1  -  12  681  1  - 8  681  1  - 8  738  1  -  7 6 6  1  -  11  9 0 8  2  -  0  10  1  day  1  "  568  1  1  "  7 3 8  1  3  "  681  1  - 8  7 3 8  1  -  681  1  - 8  birth 1  day  2  "  birth Only pen—born  X  Wt (gm)  - 4 —  10  10  9 5 3  2  -  1090  2  - 4  1  7 2 2  1  - 7  A l l live neonatants  12  15  728  7 6 7  82  129  24  3 3  +52  +71  Captive animals weaned^2, to 3 months, weighed 7 to 1 0 lbs ( F i g . 8 ) , and at one year, the hind leg and t o t a l length had almost reached adult s i z e . In wild south Texas animals body weight was s t i l l considerably less than f o r mature adults at one year (Rig. 8 , Table 3 ) . Pen—reared animals fed ad libitum on a good diet reached adult body weight of 5 0 lbs at just under 1 1 / 2 years and peak adult weights fluctuated around 6 0 l b s ( F i g . 8 ) . Wild peccaries did not reach t h i s weight u n t i l they were well into t h e i r t h i r d year, and peak adult weights fluctuated around 5 0 l b s . Peak weight was reached around 5 years and there was a s l i g h t decline i n weight of the collected animals older than 6 years ( F i g . 9 and  10).  The data shown in Figures 8 , 9 , and 1 0 indicate that the south Texas peccaries do not grow at the potential rate shown by the pen—raised peccaries. Data from young west Texas peccaries were too few f o r meaningful comparison. Weights of 1 and 2 . year o l d west Texas animals were heavier than south Texas animals in Figures 9 and 1 0 because the average age of the f a l l collected west Texas animals was older than that of the south Texas animals who were collected throughout the year. Live weight of south Texas peccaries 3 years and older collected during the study averaged 5 1 . 2 lbs f o r males and 5 2 . 0 lbs f o r females  CJ O  F i g u r e 8.  R e l a t i o n s h i p o f l i v e weights to age o f pen—reared (•) and c o l l e c t e d (o) south Texas p e c c a r i e s . Values g i v e n a r e the mean and confidence i n t e r v a l .  LIVE  WT  (pounds)  AGE  ( months)  39.  F i g u r e 9.  C a r c a s s w e i g h t s o f south ( 0 ) and west ( • ) Texas male peccaries.. V a l u e s g i v e n a r e mean, 95°/> c o n f i d e n c e i n t e r v a l , and t h e range.  F i g u r e 10.  Carcass weights o f south ( ) and west ( • ) Texas female peccaries. V a l u e s g i v e n a s f o r F i g u r e 9. 0  40,  50. Carcass Wt (lbs)  40.  if}--  30.  20  N =  l  14  11 22  4  3  6  »  4  AGE IYRS) 1  5  0  6  2  1  7  2  10  >7  37  27  >2  MALES  C a r c a s s Wt.  (lbs)  40  §11  30.  20. N =  6  12  AGE IYRS) 1  8 14  2  7 4  3  4 6  11  4  2  5  FEMALES  6 3  6  2 0  7  18  4  >7  46 23  >2  41.. (Appendix D). The difference i n l i v e weight between sexes was not significant. are  68°/o  Carcass weights expressed as a percentage of l i v e weight  (56-77%) f o r males, and 62.3% (55-78%) f o r females.  In carcass  weights of animals 3 years and older, males averaged 34.9 l b s . and females 32.0 l b s . (Appendix D) and males were s i g n i f i c a n t l y heavier (P = .01) than females because of s i g n i f i c a n t l y heavier heads and forequarters on older males (P = .01) (unpublished data). Appendix D also l i s t s age s p e c i f i c t o t a l length, hind l e g length, arid g i r t h of south Texas peccaries. West Texas peccaries were s l i g h t l y l i g h t e r , but longer legged than south Texas peccaries (Table 4).  Live weights from west Texas peccaries  were obtained on only nine animals 3 years or older, too few to be meaningful, Carcass weights averaged 33.4 pounds f o r 27 males and 30.9 pounds f o r 25 females 3 years and over.  The difference between sexes i s s i g n i f i c a n t  (P < .01). The west Texas males averaged 1.5 lbs l i g h t e r than south Texas males (P < .1) ( F i g . 9). West Texas females were only 1.1 l b s l i g h t e r than those from south Texas (P < .2) ( F i g . 10). I t should be noted that most of the west Texas animals were collected i n early winter, a time of peak weight in south Texas peccaries, and presumably also a time of peak weight i n west Texas peccaries. Table 4.  Size comparison of adult peccaries from south and west Texas.  Carcass Weight (lb) Age South Texas 3-15 yr. West Texas 3-9yr. .difference  Male 34.9+1.4 33.4+1.9 1.5 l b s  n Female n Difference P (32) 32.0+1 ..'2 (46) 2.9 lbs .01 (27) 30.9+1.7 (25) 2.5 lbs .01 n.s. 1.1 l b s n.s.  Total Length (inches) South Texas 3-15 yr West Texas 3-9 y r difference  38.2+.5 (38) 38.9+.4 (48) 37.9+.8 (27) 38.1+.9 (26) .3 inches n.s. .8 inches n.s.  Hind Foot Length (inches) South Texas 3-15 yr West Texas 3-9 y r difference  7.2+.1 (38) 7.2+.1 (48) 0 7.5+.1 (15) 7.5+.1 (16) 0 .3 inches P .01 .3 inches P .01  0.7 i n .05 0.2 ns  There was l i t t l e difference i n the t o t a l length measurement of the peccaries from the two regions (Table 4).  Males were s l i g h t l y shorter  than females i n both areas, but the difference was s i g n i f i c a n t only i n south Texas.  Hind l e g length was the same f o r both sexes, and was s i g -  42. n i f i c a n t l y longer i n west Texas animals than i n south Texas peccaries (P < .01) (Table 4 ) . There was some change i n carcass weights of animals c o l l e c t e d under d i f f e r e n t r a i n f a l l conditions.  The average carcass weights of  peccaries c o l l e c t e d during the period of good r a i n f a l l i n 1965-66 were 1.7 l b s (5/o) f o r males, and 3.6 l b s (12°/O) f o r femal es, heavier than those c  c o l l e c t e d during the 1964-65, and 1966-67 droughts (P = .2 f o r males, and P = .01 f o r females) (Table 5 ) . Although p r e c i p i t a t i o n and vegetation growth i n west Texas were generally b e t t e r i n 1966, and animals were i n s l i g h t l y better c o n d i t i o n , the data on carcass weights from the two years f o r both sexes are equivocal. Females were 0.8 l b s l i g h t e r i n 1966 (P = .3), and males were 2.9 l b s heavier i n 1966 (P < .1) than they were i n 1965 (Table 5 ) . Table 5.  Comparison:.of carcass weights of adult peccaries i n low and high r a i n f a l l periods.  Conditions West Texas 1965, low pptn 1966, High pptn difference South Texas pptn above avg. pptn below avg. difference  \  Male-  (2+ yr)  Female  (2+ y r )  32.6+1.8 35.5+3.2 2.9 "[1966)-  Mil (13) n.s. (P<.1)  31.3+2.1 30.5+3.8 0.8"[l965)  35.6+2.2 33.8+2.0  (18) (22)  33.6+1.4 (26) 30.1+1.7 (17) 3.6 Tgood yr) (P < .01)  1.7Xgoodyr)  n.s. (P  <.2)  ho] (10) n.s.  Weight changes of w i l d peccaries appear to have a basic seasonal pattern which i s not apparent i n pen-reared animals.  F i g 11 (females) and  12 ( males) show that weights of trapped and c o l l e c t e d peccaries older than two years were depressed i n early summer, dropped f u r t h e r during the summer dry period, and increased again through the wet winter of 1965-66.  Males  continued to gain weight through to the summer dry period of 1966. Females l o s t weight e a r l i e r i n 1966, perhaps due to presence of s u c k l i n g young. Weights remained low through the f a l l of 1966 and u n t i l l a t e s p r i n g , 1967, when they rose at the time when a small mast crop and some new vegetation were produced.  Figure T'il Live and carcass weights of trapped and c o l l e c t e d female peccaries older than two years from south Texas. Values given are mean, standard error at the t „ l e v e l and the r a i ge. '• n  44.  Sample s i z e 2  21  5  (live)  11  5 - 2  5  60  55  50  g  45  -p *i—I  ^  CD  35  30  25 Sample s i z e > 2 1 3  £ 20 196  (hog-dressed) 6 1 2 5 8  [mar-apr 'may ^un july-aug sept-  I  1  1965  1  ' nov - I ; d e c  1  .MOIST'  a n  , e b  .  ' m-a  * m- j  3 ' \-a  1966  1 ' s-o  W-dec lion-feb'm - a 1  '  m - i 'iuly-auq'  1967  DROlIIGWi  Figure 12. L i v e and carcass weights of trapped and c o l l e c t e d male peccaries older than two years from south Texas. Values given are mean, standard error a t the t level, and the range.  45.  4.4  The  4.4.1.  populations Density Densities of the four peccary populations that were studied de-  creased on an east-west gradient as did p r e c i p i t a t i o n ( F i g . 1). count of peccaries was possible on the Welder Refuge.  A total  A maximum of  120  peccaries was reported from a combined a e r i a l and t e r r e s t r i a l survey i n the spring of 1966.  This represents a density of 10 peccaries/sq mile.  t o t a l counts were not obtained i n 1965  and 1967,  i t was  were almost 100 peccaries present i n the spring of 1965, in the spring of 1967.  Although  estimated that there and fewer than 80  These represent densities of 8.3 and 6.7  peccaries/sq  mile. On the King Ranch, density was counts.  estimated on the basis of s t r i p  These were continued f o r 18 months and yielded estimates that  varied from 10.7  to 49.2  peccaries/sq mile, and the mean density was  21.8  peccaries/sq mile (Table 6). Table 6.  Peccary density estimates i n Mesquite Pasture of the King Ranch from s t r i p census.  Sept, 1964 Feb-Apr, 1965 Apr-July,1965 July-Dec,1965 Feb-May, 1966  No. of Counts Pita Mill 15 Pita Mill 5 Escondido 3 Mill 14 Escondido Mill Escondido 5 Mill Mean  Avg No Peccaries per Count 7.3 33. 19.7  h  Trans Area (Acres) 436 436 580  S.D. 7.6 26.2 17.6  CV. 104 79 89  4.4  4.0  91  167  16.8  10.8  8.7  81  335  20.6  9  density  21 .8  a - Standard Deviation g ^ b - C o e f f i c i e n t of V a r i a t i a t i o n = ' Avg Peccary density in the a r i d west Texas areas was than i n south Texas.  x  considerably lower  An estimate of the density on the Watson Ranch, based on  sightings by myself and ranchhands, was s l i g h t l y more than 3.1 mile.  Density (per sq) (mile) 10.7 49.2 21 .5  This i s probably a conservative estimate.  peccaries/sq  The peccary population on  the Black Gap Management Area determined from sightings, hunter reports, and the annual k i l l , has been estimated at about 6.4  peccaries/sq mile (L.S.  46,  Brownlee, Pers. Comm.).  However, t h i s estimate i s probably  liberal.  Although the density of peccaries i n each of the areas could not be determined p r e c i s e l y the d i f f e r e n c e s i n population density i n the two regions are of such magnitude as to be unmistakable Table  7.  (Table 7 ) .  Peccary density estimates on four study areas i n south and west Texas. Density (Peccaries/sq mile)  Area . South Texas King Ranch Welder Refuge  1963  1965  1966  17.8  22.9  20.6  West Texas Watson Ranch Black Gap M.A.  4.4.2.  1967  Mean  9.8  20.4 9.8  3.2 6.4  3.2 6.4  Home Range and Movements As f u r t h e r evidence o f d i f f e r e n c e s i n population density, the  s i z e s o f the home ranges were determined. and home ranges are quite small.  Peccaries are non-migratory  My observations of ear-tagged and radio  transmitter-tagged peccaries i n d i c a t e a home range o f l e s s than 3/4 sq mile (480 acres) f o r animals on the King Rianch and the Welder Refuge.  Two herds  on the King Ranch had minimum home ranges of 390 acres and 300 acres respectively.  The Venado Bend herd on the Welder Refuge had a home range of about  440 acres. On the Watson Ranch i n the more a r i d part o f Texas, three herds were observed to move f r e e l y w i t h i n areas up to 4 sq miles.  These areas included  adjacent mesas and t h e i r associated arroyos. There were some exceptions to the small home ranges i n south Texas, but these might b e t t e r be termed wanderings.  One adult male peccary tagged at  trap 3 i n Mesquite Pasture was k i l l e d about two mile NE on the P i t a - G u t t i e r e z f e n c e l i n e . (G. Schacherl, Pers. Comm.).  Another male trapped on the east  fence of P i t a Pasture was released at Trap 3, two miles away, and observed 6 months l a t e r back at the point of capture.  4 7 .  Population Structure  4 . 4 . 3 .  Sex Ratio Sex r a t i o s of peccaries change considerably with age i n both south and west Texas populations (Table 8 ) .  L i t t e r s obtained i n utero from 3 4 sows  i n south Texas y i e l d e d 6 1 foetuses D f which 5 5 could be r e a d i l y sexed. sex r a t i o favoured females  (42°/o  males to  58°/>  The  females) . When the s i n g l e west  Texas l i t t e r , and the 3 2 foetuses born i n c a p t i v i t y were added the r a t i o was nearer to equal, but s t i l l favoured females, Table 8 .  foetuses mo 4 - 1 2 mo 1 3 - 3 6 mo 3 - 7 yr 7 + yrs 1+ yrs 3  47°/o  males to  5 3 %  females.  Age s p e c i f i c sex r a t i o s of pen-born, south Texas and west Texas' peccaries. West Texas Collections  T e x a s S o u t h C o l l e c t i o n s Trapping Total 4 2 : 5 8  (55)  4 2 : 5 8  (55)  6 4 : 3 6  (11)  7 0 : 3 0  (20)  6 8 : 3 2  (31)  5 0 : 5 0  6 0 : 4 0  (20)  5 4 : 4 6  (40)  5 6 : 4 4  (60)  5 5 : 4 5  (22)  5 7 : 4 3  1 0 0 : 0  5 2 : 4 8  (27)  5 2 : 4 8  (27)  4 8 : 5 2  (60)  4 8 : 5 2  (60)  4 6 : 5 4  4 2 : 6 8  (31  3 2 : 6 8  (31]  5 0 : 5 0  4 4 : 5 6  (120)  4 3 : 5 7  (232)  5 3 : 4 7  Note:  ] 4 1 : 5 9 ( 1 1 2 J  Captives (32)  4 7 : 5 3  (21)  6 7 : 3 3  (54)  5 5 : 4 5  (81)  (60)  5 5 : 4 5  (87)  (28)  4 8 : 5 2  (88)  3 6 : 6 4  (39)  (2) (2)  5 6 : 4 4  Total  6 2 : 3 8  96  (89)  4 6 : 5 4 ( 3 2 8 )  Sex r a t i o i s % Males:% Females (Sample s i z e ) .  The sex r a t i o s made an abrupt, although temporary, r e v e r s a l at b i r t h . Sex r a t i o s o f young l e s s than three months o l d strongly favoured males to 3 3 % females (Table 8 ) .  males,,67%  Between 3 and 7 years the sex r a t i o s became  equal, and i n animals o l d e r than 7 years, the sex r a t i o strongly favoured females ( 3 2 % males to 6 8 % females) i n south Texas.  The average sex r a t i o  f o r animals o l d e r than 1 2 months i n south Texas determined from 1 1 2 l i v e trapped and 1 2 0 c o l l e c t e d animals favoured females ( 4 3 % males to 5 7 % females). In west Texas the average sex r a t i o f o r a l l animals o l d e r than 1 2 months was 5 3 % males to 4 7 % females, but f o r the 3—to—7—year c l a s s the r a t i o favoured females ( 4 6 % males to 5 4 % females). When the c o l l e c t e d foetuses, c o l l e c t e d young, and trapped young from south Texas were divided i n t o three categories (minor drought, above average p r e c i p i t a t i o n , and drought conditions) there was no consistent trend between the sex r a t i o s f o r the three periods (Table 9 ) .  4 8 .  Table 9 .  Age s p e c i f i c sex r a t i o s of young south Texas peccaries ^ conceived or born under d i f f e r e n t c l i m a t i c c o n d i t i o n s .  foetuses 3  mo  4 - 1 2  mo  Total Note:  Minor ^ Drought  Drought  4 4 : 5 6 ( 4 1 J  5 0 : 5 0 ( 6 )  2 5 : 7 5 ( 8 }  4 2 : 5 8 ( 5 5 )  Moist  Total  6 9 : 3 1 ( 1 6 )  7 1 : 2 9 ( 7 )  6 0 : 4 0 ( 5 )  6 8 : 3 2 ( 2 8 )  6 0 : 4 0 ( 3 0 )  5 6 : 4 4 ( 1 6 )  6 4 : 3 6 ( 1 4 )  5 6 : 4 4 ( 6 0 )  5 4 : 4 6 ( 8 7 )  5 9 : 4 1 ( 2 9 )  5 2 : 4 8 ( 2 7 )  5 5 : 4 5 ( 1 4 3 )  a - above average p r e c i p i t a t i o n and range conditions, June, 1 9 6 5 to June, 1 9 6 6 . b - terminal portion of minor drought, to M a y , . 1 9 6 5 . c - drought conditions J u l y , 1 9 6 6 to Aug. 1 9 6 7 . d - r a t i o s are °/o males to °/o females (sample s i z e ) . Age S t r u c t u r e  The age s t r u c t u r e of the south Texas peccary population estimated from l i v e trapped and c o l l e c t e d samples, i s shown i n F i g . 1 3 . Since the c o l l e c t i o n s were f o r the purpose of obtaining adult specimens, the younger age classes were under—represented.  Although the bias may carry through to  the 3 - o r 4 - y e a r classes (the time when maximum s i z e i s approached) i t i s only serious f o r animals under 2 years o l d . The trapping r e s u l t s are presumably b i a s - f r e e and since the ages of these animals were determined as j u v e n i l e s , (under 1 2 months) young adults ( 1 to 2 years) and older a d u l t s , I have incorporated these j u v e n i l e s and young adults i n t o the ,age s t r u c t u r e curve.  Of 1 6 7 peccaries trapped, 5 9 were l e s s than 1 year o l d . The animals  l e s s than 1 year o l d that were c o l l e c t e d were replaced i n the population age curve with the correct proportion determined from the trapped sample.  The  sex r a t i o s of the two samples were almost i d e n t i c a l , so there was no problem i n aportioning the sample between sexes. year o l d s .  The same was done f o r the 1. to 2  In t h i s group there were several animals i n i t i a l l y classed as  young adults that were l a t e r estimated at 2 6 months o l d , so the age curve may over—represent t h i s age c l a s s s l i g h t l y . The ages determined by dental annulations showed that almost 15 /o c  of the south Texas sample i s over 7 years o l d . The oldest animal obtained was a 1 5 - y e a r o l d female. Figure 1 3 also shows the age s t r u c t u r e of the west Texas c o l l e c t i o n s , i n c l u d i n g both the Black Gap and Watson Ranch samples as there was l i t t l e d i f f e r e n c e i n the age s t r u c t u r e of the two samples.  I t was not p o s s i b l e to  c o r r e c t f o r the under-representation of young animals i n west Texas as was  49.  WEST TEXAS  0 •  30%  m a l e s (n=64) f e m a l e s (n=55)  20%  10%  <1  1  2  3  4  5  • 1 In In m l ! 6  7  10  8.  11 12 13  14 15  AGE IN YgkRS  40$  30% •  SOUTH TEXAS  OU m a l e s (n=109) • f e m a l e s (n=109)  10%  <1  1  2  3  4  5 ' 6  7  JZ1  8  AGE IN YEARS  9  10  HI rrrr-i  11 12 13  r m  r—1  14 15  Figure 1"3.Age d i s t r i b u t i o n of peccaries c o l l e c t e d and trapped i n south Texas and c o l l e c t e d i n west Texas.  50. done f o r the south Texas population.  Hence, the two curves are not comparable  in the youngest age classes. It i s apparent from comparison of the two populations that the west Texas population i s much younger than the south Texas population, and that the 2 to 3 year olds make up the largest part of the adult population. No animals over an estimated 9 years old were obtained i n west Texas. With the ages of the animals estimated to the year, i t was possible to  construct l i f e tables for the south and west Texas populations (Tables 10  and 11). at  In south Texas, the data obtained from trapped animals under 2 years  i n i t i a l trapping and the collected animals over 2 years are assumed to  represent the proportions of each age class l i v i n g at the s t a r t of that age i n t e r v a l ( l ). The shrinkage between each group then gives a measure of the mortality (d ) during that age i n t e r v a l .  The sample was collected over a  2 1/2 year period and partly overcomes the i r r e g u l a r addition of young to the population each year as Deevey (1947:298; 1964) suggests.  The high  survival i n 1966 and low survival i n 1967 tend to average out, and render mean mortality figures useful.  Anomalies are s t i l l present i n the table,  presumably because of sample size, sample selection, or unequal b i r t h and survival rates during some periods. Examination of the trends i n the l i f e expectancy column of Table 10 emphasize the higher mortality i n the early and l a t e r years and the lower mortality rate between the ages of 2 to 7 years.  The mean annual mortality  rate i s 21.5% f o r the population. The l i f e table for the Black Gap population (Table 11) was determined from 2 years of hunter c o l l e c t i o n s and because of the magnitude of the anomalies r e s u l t i n g from small sample size, possible unequal survival rates between periods, and non-representative c o l l e c t i o n of smaller animals less than 2 year old, the trends are not as apparent. tend to be shorter.  L i f e expectancy does however,  The annual mortality rate averages 27.5°/o.  The slopes  of the regressions of population s i z e on age f o r the two populations (Table 10 and l l ) are not s i g n i f i c a n t l y d i f f e r e n t , c h i e f l y because of limited data for  the West Texas population.  Table 10. L i f e table f o r south Texas peccaries based on 218 animals c o l l e c t e d and trapped on the King Ranch (see text f o r d e t a i l s ) . Age (years)  0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 *  - x no. at s t a r t of interval 1  64 44 19 12 11 19 14 4 11 7 4 1 3 2 2 r1  x life expectancy e  x no. d,:y ing during interval  mortality rate  20 25 7 1 + 8 5 10 + 7 4 3 3 + 2 1 0 1 1 '  .31 .57 .37 .08 + .73 .26 .71 +1 .75 .36 .43 .75 ' +2.00 .33 .00 .50 1 .00  d  2.9 3.0 5.2 7.0 6.6 * 3.0 2.9 8.2 * 2.3 2.4 2.7 8.5 * 2.2 2.0 1 .0 0.5  anomalies due to sample s i z e , sample s e l e c t i o n , or unequal b i r t h or survival rates. Y = 3.76 - .24X .., R = .925 Y = population s i z e , x = age  Table 11 .  Age (years)  1 2 3 4 5 6 7 8 9  L i f e t a b l e f o r 102 Black Gap peccaries over 12 months o l d c o l l e c t e d by hunters. x no. at s t a r t of interval 1  26 34 3 13 16 3 1 1 5  Y = 3.35 - .32X\ , R = .715 notes as f o r table .10.  no. d y.dng during interval + 8 31 +10 + 3 13 2 0 + 4 5  3x  mortality rate + .38 . .91 +3.33 + .39 .81 .66 .00 +4.00 1 .00  x life expectancy e  3.4 * 1 .7 13.7 * 2.5 * 2.9 2.8 6.5 5.5 * 0.5  52. 4.5.  Male reproduction  4.5.1.  Morphology of the Male Reproductive Tract. The basic anatomy of the male reproductive t r a c t i s s i m i l a r to  that of the domestic boar described by Nalbandov (1958) and Mann (1969). The f o l l o w i n g d e s c r i p t i o n i s of the t r a c t of a 3 1/2 year o l d male (Pc 183), shown i n P l a t e 2. The t e s t e s are 1 3/4 inches long by 1 1/4 inches diameter. The vas deferens i s 9 1/2 inches long, with no terminal ampulla.  The seminal  v e s i c l e s are w e l l developed t r i a n g u l a r s t r u c t u r e s 2 1/2 inches by 1 1/2 inches by 1 inch deep. Jhe prostate gland forms a 3/4 inch diameter sphere around the juncture of the vas deferens, seminal v e s i c l e and urethra. The w e l l developed bulbourethral gland i s an elongated tube 3 1/4 inches long with a diameter of 1 1/8 inch.  The penis i s about 9 1/2 inches from i t s  pubic attachment and has the t y p i c a l "cork-screw" shape and reverse f l e x u r e of the domestic p i g . 4.5.2.  Growth and Seasonal Change i n T e s t i s S i z e . •ne hundred and eighteen p a i r s of t e s t e s were examined from pec-  c a r i e s from south arid west Texas and from captive animals.  The t e s t e s were  s c r o t a l from at l e a s t one month p r i o r to b i r t h and remained that way throughout t h a animal's l i f e t i m e . At b i r t h the testes had a s i z e index (T.I. = t e s t i s weight -\- hind l e g length) of 0.03.  Growth was r e l a t i v e l y slow f o r 7 to 8 months.  There  was then a sharp gain i n the t e s t i s index of south Texas peccaries from 0.4 to 1.0 between 9 and 10 months. (Fig.14, Table 12).  The t e s t e s approached  adult s i z e by 18 months and gradually increased to a TI of 3.06 at 5 years, and the plateau was maintained through 7 years (Table 13).  Over t h i s age the  index d e c l i n e d . s l i g h t l y to a mean of 2.7 f o r a l l animals o l d e r than 7 years. Table 12. Growth i n t e s t e s f o r young south Texas peccaries.  Age 1 day .2 y r s .3 .5 .6 .7 .8 1 .5 1 .8 2.2  wt n 1 1 6 1 4 1 2 2 1 5  (gm)  0.1 D.6 1 .9 2.4 2.9 6.7 6.8 17,; 4 9.1 17.3  T.I. X  .03 .12 .35 .38 .44 . .92 1 .04 2.4 1 .2 2.46  Index Range  95°/o  SD  Sx  Conf. Lim  .16-.55  13  .05  .13  .3-.54  .11  .06  .18  .53  .24  .65  .98-1.1 2.1 -2.7 1.8 -3.0  53. Plate 2.  The male reproductive t r a c t . a.  The t r a c t removed. Note the extensive dark i n t e r s t i t i a l t i s s u e i n the t e s t i s , the l a r g e tubular bulbourethral gland, the s t r a i g h t vas deferens crossing the surface of the seminal v e s i c l e s (lower center), and the s p i r a l f l e x u r e of the penis (upper r i g h t ) .  b.  Cross-section of the t e s t i s one-third of the distance from the caput epididymis. Note the tubule clumps and the s e c r e t i o n sinuses. ( H i s t o l o g i c a l s e c t i o n ) .  c.  Cross-section of the t e s t i s i n the c e n t r a l area. Note the tubules extending towards the c e n t r a l r e t e t e s t i s . (Fresh s e c t i o n ) .  d.  Cross-section of the t e s t i s one-third of the distance cauda epididymis. Tubules converge i n c e n t r a l r e t e and connect with vasa e f f e r e n t i a below lower center p i c t u r e . The white streaks are s e c r e t i o n sinuses. i c a l section).  from the testis of (Histolog-  54.  55.  Figure 14.  Change i n t e s t i s index (Tl) with age of i n d i v i d u a l south and west Texas peccaries.  Figure 15.  Seasonal change i n t e s t i s index of adult south Texas peccaries. Mean, range and 95% confidence i n t e r v a l are given.  56.  •  •  •  Q 2  • So. Texas o West Texas  1 .  AGE  1 yr  3  4  5  6  7  S  3  3  1  9^14  3-5  3.0  ^3  r a n g e ^ ^ r-i  Q 2  ,2.5  mean-  2.0  5  J  F  6  2  12  8  J  3 J  5  A  S  O  N  D  57.  Table 13.  Age s p e c i f i c t e s t i s s i z e f o r adult south Texas peccaries.  wt T.I. n xfgm) X Age 11 3.4 2.38 2 yrs 3 5 19.2 2.68 4 5 16.5 2.4 5 8 22.2 3.06 6 8 20.4 2.83 2 22.7 3.15 7 8-14 yrs 9 19.6 2.7 48 16.3  X  Index Range 1.8-3.0 1.9-3.5 2.2-2.7 2.3-3.6 2.4-3.4 2.8-3.5  2.69  1.8-3.6  SD .41 .63 .20 .41 .36 .49 .39  Sx .12 .28 .09 .15 .02 .35 .02  .22  .001  95°/, Conf. Lim .28 .78 .25 .35 .04 4.2 .04 .002  At b i r t h , the testes of west Texas peccaries were about the same s i z e as those of south Texas animals, but growth appeared to be slower and mature s i z e was not reached u n t i l about 2 years (Fig. 14", Table 14).  Testis s i z e also peaked at about 5 years, but at an index of'2.23,  which was considerably lower than the south Texas peccaries (Table 15). Since the index i s derived using the leg length, which was s i g n i f i c a n t l y longer i n west Texas peccaries, the index appears smaller f o r west Texas animals.  However, the mean weight of testes from south Texas 2-year old  peccaries was 3.4 gm heavier (P <  .01) than weights of those from west  Texas 2-year old peccaries. Table 14.  Age .1 .3 .4 .7 .8 1 .0 1 .3 1 .6 1 .8  Growth i n testes f o r young west Texas peccaries  n 1 1 4 1 1 3 1 2 1  wt x (gm V ' 0.3 )x.067 0.5 .085 1 .4 .185 .59 4.0 5.2 .74 5.2 .71 6.0 .8 10.5 1 .4 12.0 1 .5 1  Index Range  SD  Sx  Sxt.05  .15-.29  .07  .035  .110  .4-.93 1 .2-1 .6  58. Table 15.  Age s p e c i f i c t e s t i s size f o r adult west Texas peccaries.  wt n Age 17 2 yrs 2 3 yrs 3 4 yrs 3 5 yrs 7-9 yrs 5 30  X  T.I. (gni)x 13.7 1 .86 14.6 2.04 13.0 1 .67 16.7 2.23 15.3 2.06  Index Range 1.3-2.4 1.8-2.3 1 .5-1.9 1.8-2.6 1.1-2.8  SD .34 .37 .21 .40 .77  Sx .08 .26 .12 .23 .34  Sxt.05 .17 3.12 .52 • 1 .00 .96  14.3 1 .88.  1.1-2.8  .45  .08  0.16  K  There appeared to be a seasonal change i n t e s t i s size i n mature animals.  The TI was high from March through-July, and low from August  through to February ( F i g . 15).  The testes were available from only one  adult male i n the period November through January; however, the TI of 17 adult males collected i n August, September, October and February averaged 2.42 whereas the March-July sample had an average index of 2.84 0.34,  (difference  P.< .05) . The s i z e difference between testes from west and south Texas  peccaries i s probably related to condition.  Pen—reared peccaries had  testis--weights and indices much higher than the south Texas peccaries who, in turn, had heavier testes than the west Texas peccaries (cf. Tables 12— 16).  This showed the same pattern as the condition index.  Comparison of  the TI of males collected i n south Texas between June, 1965, to June, (moist conditions), and July, 1966, to August, 1967 showed l i t t l e difference Table 17.  1966  (draught conditions)  However, when the unequal d i s t r i b u t i o n  of samples through the season was controlled by taking data only from prime animals collected during the spring and early summer of both periods, the TI was s l i g h t l y higher from the animals collected during the period of good conditions (Table 17).  One exception to these g e n e r a l i t i e s  was  a 2.1 year old west Texas male, BG 537, who had a TI of 4.3, and t e s t i s weight of 32 gm.  This animal was not included i n the s t a t i s t i c a l t r e a t -  ments because of the abnormal s i z e of the testes, although they appeared normal otherwise.  59.  Table 16.  T e s t i s weights and i n d i c e s o f pen-reared peccaries.  Age 1 da. .3 y r . .4 y r . 1.5 y r . 1.8 y r . 3.0 y r .  Table 17.  n 3 2 y r s 27 .  n 1 3 1 2 1 3  wt xfgm)  0.1 2.1 3.8 18.7 18.2 24.9  Tl  Range  X  .03 .40 .65 2.6 3.2 3.5  .32-.55 2.1-3.1 3.0-4.0  T e s t i s s i z e o f south Texas adult peccaries compared by drought c o n d i t i o n s . wt Tl x (gm)x 18.2 2.8  Range 2.6-3.1  SD .25  Sx .15  19.1  2.6  1.9-3.6  .45  .09  18.72 2.6  1.8-3.4  .31  .10  2.8-3.6  .34  .15  0.4  2.7-3.4  .25  .09  0.2  c  &  older 19  3 to . 5 20.0 3.3 years old 8 21 .1 3.1  ^.Conditions Conf. Periods .6 mild drought Mar-May 1965 .18 moist June/65—June/66 .39 drought July/66-Aug/67  95 /a  r  l  moist June/65—Aug/65  '  Adult west Texas peccaries c o l l e c t e d during November and December on the Black Gap area showed a s l i g h t (but not s i g n i f i c a n t ) increase i n t e s t i c u l a r weights from November to December.  This c o l l e c t i n g  period was only three weeks long and therefore a s i g n i f i c a n t d i f f e r e n c e would be u n l i k e l y .  When' 1965 data (low r a i n f a l l ) were compared with 1966  data (high r a i n f a l l ) , however, the 1966 t e s t i s i n d i c e s were s i g n i f i c a n t l y higher (P<.05) than 1965 t e s t i s i n d i c e s (Table 18).  60. Table 18.  Testis size of west Texas adult peccaries (2 years and older) compared by month and year.  P e r i o d 1965 & 1966 Dry 1965 Moist1966 4.5.3.  n Nov. Dec. Nov. & Dec. Jan. - Dec. Nov. & Dec. Nov. & Dec.  13 13 26 33 9 17  wt TI x (gm ) x 14.1 14.7 14.4 13.7 13.2 15.03  1 .86 2.0 1 .93 1 .88 1 .77 2.02  Range 1.1-2.8 1 .3-2.6 1.1-2.8 1.1-2.8 1.1-2.4 1.4-2.8  SD  Sx  .50 .37 .45 .45 .46 .42  .14 .10 .09 .08 .15 .10  95% Conf .31 .23 .18 .16 .36 .22  H i s t o l o g i c a l Examination of Testes Testes are not homogeneous through t h e i r length; the tubules  drain into the central rete t e s t i s , and hence through the vasa e f f e r e n t i a to  the caput epididymis (Plate 2 b, c, and d).  These differences were of  l i t t l e consequence i n t h i s study because a l l of the t e s t i s sections f o r h i s t o l o g i c a l comparison were taken from the mid-section of the t e s t i s (Plate 2c), and the error introduced by location was minimal.  Tubule  lumina were r e l a t i v e l y empty near the periphery of the t e s t i s , but towards the  center, they became f i l l e d with s l u f f e d c e l l s and detritus.  This same  detritus was also present i n the rete, vasa e f f e r e n t i a and epididymis, and was present i n a l l adult peccaries. At  b i r t h , the t e s t i c u l a r tubules were r e l a t i v e l y small, 54 JJ  diameter, and made up only 1/3 of the mass of the t e s t i s ( F i g . 16, E).  At t h i s time there were only spermatogonia and S e r t o l i c e l l s present  in the tubule. to  Appendix  four months.  The spermatogonia began to form spermatocytes between three At t h i s time the tubules were s t i l l only 1/3 of the t e s t -  i c u l a r mass, the TI = .34, and the tubule diameter was about 60 p.  There  was l i t t l e change i n r e l a t i v e s i z e and proportion i n the t e s t i s u n t i l about 8 months, when concurrent with the rapid growth of the testes, spermatocytes became common and occasional spermatids appeared i n the tubules.  The  tubules reached 115 JJ diameter, although they were s t i l l l i t t l e more than a t h i r d of the volume of the t e s t i s .  Between 9 to 10 months, when the  TI = 1.0, a few spermatozoa appeared' i n the tubules. ule  diameter averaged s l i g h t l y greater than 125  increased to 40% of the t e s t i s volume.  At this time the tub-  and the tubules had  Spermatozoa did not become common  u n t i l the animal approached 11 months (average 35.6 sperm/tubule crosssection)  when the tubule diameters exceeded 150 y and were 50% of the  • cn _^  Figure 16.  Change i n t e s t i s index, sperm counts (per tubule cross-section"), proportion of tubules (%), and tubule diameter (u) with age of 41 south Texas peccaries.  63. t e s t i s volume.  I t was around t h i s age that pen-reared males s u c c e s s f u l l y  f e r t i l i z e d sows  10.7 months i n Arizona (Sowls, 1966)  and 11.6  and  11.8 months at U.B.C. and the Welder Refuge ( t h i s study). I did not f i n d a tubule cross-section with over 100 spermatozoa u n t i l the male was over 2 years o l d when"diameter was 173 JJ and comprised 72% of the t e s t i s .  tubules  Tubule diameter appeared to reach i t s maximum  s i z e , over 200 JJ, by 2 1/2 years ( F i g . 16), and i t appeared to be maintained to at l e a s t 9 years.  A 12- and a 14-year o l d male both showed  s l i g h t l y smaller average tubule s i z e , 181 and 182 JJ, but spermatozoa s t i l l averaged 155 and 76 per tubule c r o s s - s e c t i o n . The proportion of the adult t e s t i s comprising tubules varied between 60% and 8D°/o; but i n the 12-year o l d male i t was only 54%, and i n the 14-year o l d , 81/o. c  I t should be noted that the 12-year o l d male (P-5)  had a poorly developed (12.9 gm) r i g h t t e s t i s .  The tubules were quite  l a r g e (154 JJ) i n the small r i g h t t e s t i s and an average of 60.6  spermatozoa  per tubule, c r o s s — s e c t i o n were present, but the tubules were only 13% of the t e s t i s .  The l e f t t e s t i s appeared normal except that some of the tubules  had t h i c k connective t i s s u e w a l l s . 4.5.4.  Seasonal Changes i n H i s t o l o g i c a l Structure of Testes The small sample s i z e and the f a c t that the testes analysed were  chosen because they were average or below average s i z e preclude f i r m conc l u s i o n s of seasonal change i n t e s t i s s t r u c t u r e .  The proportion of the  t e s t i s comprised of tubules tended to be higher i n the l a t e spring and summer and lower i n the f a l l ( F i g . 17), l i k e the t e s t i s index.  Conversely,  the i n t e r s t i t i a l t i s s u e , i n c l u d i n g the secretory c e l l s , comprised a higher proportion of the t e s t i s volume i n the f a l l .  M u l t i p l y i n g the  percent  i n t e r s t i t i a l t i s s u e by the t e s t i s weight to adjust f o r the change i n t e s t i s weight, i n d i c a t e d that more secretory i n t e r s t i t i a l t i s s u e was present i n the f a l l and winter than i n the summer. The diameter of the tubules, and the number of sperm per tubule c r o s s - s e c t i o n , appeared to be i n v e r s e l y r e l a t e d to the proportion of the t e s t i s comprised of tubules ( F i g . 17).  Thus i t appears that as the pro-  portion of the i n t e r s t i t i a l t i s s u e increased, the tubules became l a r g e r and the number of sperm per tubule cross-section increased.  Since there  a decrease i n the s i z e of the t e s t i s i n the f a l l , there was probably  was little  Figure 1°7. Seasonal changes i n t e s t i s s i z e and h i s t o l o g i c a l structures of 18 adult south Texas peccaries.  65. increase i n the t o t a l number of sperm produced.  However, at a l l seasons  sperm production appeared to be s u f f i c i e n t f o r f e r t i l i z a t i o n . Comparison of h i s t o l o g i c a l s t r u c t u r e between the moist and dry years i s tenuous because only one adult from each of s i x corresponding months was examined h i s t o l o g i c a l l y .  A o n e - t a i l e d paired " t " t e s t showed  a s i g n i f i c a n t d i f f e r e n c e only i n the number of sperm (P< .05) between these periods.  The number of sperm present i n the dry year was s t i l l much  higher than i n males at f i r s t maturity and there can be l i t t l e doubt that males i n the dry period were s t i l l  fertile.  The west Texas males followed the same pattern as the south Texas males, although they have fewer sperm and r e l a t i v e l y more i n t e r s t i t i a l t i s s u e (Appendix E). 4.6.  Female reproduction  4.6.1.  The Reproductive Tract and Mammae. Description of the reproductive t r a c t was based upon the t r a c t s  from a 16 month o l d v i r g i n and a 4 year old, peccary.  The uterus was bicornuate.  1 week post-pregnant adult  In the v i r g i n adult each horn was  about 10.5 cm long, and i n the pregnant sow, the cornua reached about 25 cm. of  The cornua were c o i l e d i n l a t e r a l h e l i c e s .  The body of the uterus  the v i r g i n adult was 3.5 cm from the c e r v i x to the c l e f t of the cornua,  and about 8 cm i n the pregnant adult. and short, 9 to 10 cm.  The F a l l o p i a n tubes were s t r a i g h t  The w e l l v a s c u l a r i z e d fimbriae of the ostium are  normally f l a c c i d , but during oestrus, become t u r g i d . the  ovaries.  They a i d not enclose  P l a t e 3a shows the reproductive t r a c t with uterus opened  and the foetuses alongside. The f o e t a l attachments are of the d i f f u s e e p i t h e l i o c h o r i a l type (Nalbandov, 1964), with a s l i g h t y l more intimate and zoned p l a c e n t a l e p i t h e l i o c h o r i a l i s than i n the domestic sow (Wislocki, 1931). There were 4 p a i r s of mammary glands i n both south and west Texas peccaries.  The two pectoral p a i r s were l i t t l e more than pigmented spots,  but the i n g u i n a l and post-abdominal p a i r s were both f u n c t i o n a l .  In  l a c t a t i n g sows, the hind p a i r was u s u a l l y l a r g e r , but o c c a s i o n a l l y the post-abdominals were l a r g e r . 4.6.2.  The Ovary. The ovaries were r e l a t i v e l y large and frequently appeared, b i -  lobed because of the presence i n pregnant sows of a large f u n c t i o n a l corpus luteum bulging from the ovarian body (Plate 3 b,c,d).  66.  P l a t e 3.  The female r e p r o d u c t i v e  tract.  a.  The t r a c t  o f a pregnant sow opened t o show f o e t u s e s .  b.  The ovary from a non-pregnant sow. Bumps, on s u r f a c e a r e follicles. The h i l a r end i s a t t h e t o p .  c.  The o v a r y from a pregnant sow. Two c o r p o r a l u t e a b u l g e from t h e o v a r y a t t h e t o p . F o l l i c l e s w e l l i n g s can be seen i n t h e body o f t h e o v a r y . The h i l a r a r e a i s a t t h e bottom.  d.  The o v a r y from a pregnant sow. One corpus luteum b u l g e s from t h e t o p o f t h e o v a r y . The h i l a r a r e a i s a t t h e bottom.  i  67.  68. The ovary was supported by the f i b r o u s mesovarium to the broad ligament. Frequently one o r more f l u i d f i l l e d cysts were present at the juncture of the mesovarium and the ovary.  These, were usually under 1 mm diameter but  o c c a s i o n a l l y up t o 4 mm, and probably did not i n f l u e n c e reproduction, as they were equally abundant i n both pregnant and non-pregnant sows. In the ovary, the medulla and cortex were c l e a r l y  distinguishable.  The medullary region was separated from the c o r t i c a l region by a very thick t u n i c a albuginea from at l e a s t 82-days post-conception (Plate 4a,b).  In f o e t a l  ovaries, the t u n i c a contained many r e l a t i v e l y small blood v e s s e l s , but i n o l d e r animals i t contained many l a r g e a r t e r i e s and blood sinuses, together with many l i p o c y t i c c e l l s (Plate 4 c ) .  The l i p o c y t i c c e l l abundance varied considerably  between animals with l i t t l e apparent r e l a t i o n s h i p to pregnancy.  These c e l l s  were also common i n the mesovarium of most animals. The ovary i n an 82-day conceptus weighed .02 gms and had a volume of .01 c c . I t contained a l a r g e medulla, .001 cc (10% of ovary volume),  encased  i n a r e l a t i v e l y wide connective t i s s u e t u n i c , and a wide cortex f i l l e d with many cords (Plate 4a).  A few tubule ' f o c i ' were v i s i b l e i n the medulla, and  associated prominently with the medulla i n the h i l a r area was the r e t e o v a r i i , the mesonephric u r o g e n i t a l connection.  By 115—days post—conception, the  medullary tubules had increased and expanded but the medulla had assumed a l e s s e r p o r t i o n of the ovary (3.2%).  The c e l l s of the tubules appeared to be  S e r t o l i c e l l s , as Leach and Conaway (1963) found i n the skunk.  At b i r t h , the  s i z e of the medulla increased s l i g h t l y to 7.2% of the ovary.  The medullary  tubules were quite obvious, scattered i n clumps (Plate 4 b).  The r e t e was  also s t i l l  prominent. At 6 months ( s t i l l 2 to 5 months before the f i r s t p o s s i b l e preg-  nancy) , the ovary had increased to 0.7 gm, and 0.4 cc, and the medulla to 0.2 cc (50% of ovary volume).  Medullary tubules were no longer d i s t i n c t ,  but the i n t e r s t i t i a l c e l l s were arranged i n an extensive connective t i s s u e reticulum.  In none of the adult south Texas or pen—reared sows were the  medullary tubules evident, but i n the west Texas c o l l e c t i o n , s e v e r a l of the o l d e r sows had d i s t i n c t tubules complete with lumina (Plate 4 d).  Microscopic  appearance of the i n t e r s t i t i a l c e l l s of the ovarian medulla i n pregnant adults was s i m i l a r to the appearance of the t e s t i c u l a r i n t e r s t i t i a l t i s s u e i n adult boars (Plate 4 e and f ) , and they are no doubt homologous. The r e t e o v a r i i was d i s t i n c t l y v i s i b l e i n an 82-day conceptus, i n  69.  P l a t e 4.  Ovarian s t r u c t u r e s . a.  The ovary of an 82-day o l d foetus. Note the c e n t r a l medulla surrounded by the connective t i s s u e t u n i c . The h i l a r area i s a t the bottom.  b.  The ovary of a neonatal peccary. Note the c e n t r a l medulla containtubules, and surrounded by the v a s c u l a r i z e d connective t i s s u e t u n i c . Cords are v i s i b l e i n the cortex.  c.  L i p o c y t i c c e l l s i n the outer edge of the medulla i n an adult female ovary. The medulla extends from the lower and r i g h t sides of the p i c t u r e .  d.  The medulla of a 9-year o l d west Texas sow containing tubules.  e.  The medulla of a non-pregnant sow.  Note l i p o i d granules i n the  'interstitial' cells. f.  I n t e r s t i t i a l c e l l s of the t e s t i s of an adult male.  g.  The r e t e o v a r i i (lower r i g h t ) i n a 9-year o l d west Texas sow. The medulla i s the upper portion of the p i c t u r e . The r e t e o v a r i i i n a f o e t a l peccary. The h i l a r area i s to the r i g h t , and the cortex forms the top and bottom p r o j e c t i o n s . The medulla i s to the l e f t .  h.  70.  71.  a 9-year o l d south Texas sow (Plate 4 g and h) and at several ages between. was nearly always connected with the medulla.  It  The r e t e was more prominent i n a l l  of the west Texas specimens than i n most of the south Texas and pen-reared specimens. The c o r t i c a l region of the ovary followed the normal mammalian pattern of development.  Cords were prominent i n the 82-day conceptus, and  these cords could have been developing out towards the periphery, as Gropp and Ofino (1966) have suggested f o r c a t t l e . examined to a s c e r t a i n t h i s point. birth.  A more i n t e n s i v e s e r i e s should be  The cords remained prominent u n t i l a f t e r  By b i r t h , the p r i m o r d i a l f o l l i c l e s were present and formed a d i s t i n c t  band around the periphery of the ovary ( P l a t e 5a). Appendix F (Tables 1 and 2) l i s t s the a g e - s p e c i f i c weights and volumes of the ovaries and the volumes of the medulla, corpora l u t e a and l a r g e s t f o l l i c l e s of non-pregnant and pregnant sows from south Texas and from west Texas.  The  ovary increased i n s i z e to 1.1 gm at 5 or 6 years and decreased s l i g h t l y t h e r e after.  The s i z e of the medulla f l u c t u a t e d widely but appeared to be at i t s  l a r g e s t s i z e between 1 and 5 years, a f t e r which i t gradually decreased.  Since  the s i z e of the ovary increased to 5 years, the r e l a t i v e s i z e of the medulla decreased from 40°/o at 1 year to 18°/Q at 7+ years i n south Texas, and 50°/o at 1 year to 15°/o at 7+ years i n west Texas. There was no s i g n i f i c a n t d i f f e r e n c e i n ovarian medulla s i z e of sows 2 years o l d and over between pregnant and non-pregnant animals (P <. .4) or between west Texas and south Texas sows (P < .5). The seasonal change i n medulla s i z e f o r a l l sows 2 years and o l d e r i s shown i n F i g . 18.  The pattern  i s obscure, but mid-summer s i z e tended to be l a r g e r than winter s i z e .  The  appearance of the i n t e r s t i t i a l c e l l s did change with pregnancy s t a t e .  In preg-  nant animals with f u n c t i o n a l corpora l u t e a , the medullary c e l l s appeared more regressed and contained more brown l i p o i d granules than i n the non—pregnant sows where the c e l l s appeared to be generally l a r g e , s l i g h t l y vacuolated, and secretory (Plate 5 b and c ) . The l i p o i d granules were present i n a l l adult medullas, and i t i s probably these that impart the dark brown to b a l c k i s h c o l o r to B o u i n s - f i x e d medullas. 1  The s t r u c t u r e was highly v a s c u l a r i z e d at a l l times,  and had an extensive connective t i s s u e reticulum. The c o r t i c a l region surrounded the medulla ( P l a t e 5d). Clustered sub-adjacent to the germinal epithelium were numerous nests of p r i m o r d i a l f o l l i c l e s (Plate 5 a ) .  In the stroma, were found f o l l i c l e s i n several stages,  72.  P l a t e 5.  Ovarian s t r u c t u r e s . a.  P r i m o r d i a l f o l l i c l e s i n a band around the periphery of the cortex.  b.  The medulla of a pregnant  c.  The medulla of a three month post-pregnant sow. Note the greater g r a n u l a r i t y of the c e l l s . Blood vessels are at the top of t h i s and the preceding p i c t u r e .  d.  A section of the ovary showing the s t r u c t u r e s present. At r i g h t center i s the medulla surrounded by the v a s c u l a r i z e d t u n i c . F o l l i c l e s i n various stages of development are i n the cortex. A newly framing corpus luteum i s present at the l e f t center, and a scar formed from a degenerating f o l l i c l e i s present at bottom r i g h t cerater. The h i l a r area i s to the right.  e.  A degenerating corpus luteum of non—pregnancy. e r a l absence of l a r g e blood vessels.  f.  A degenerating corpus luteum of pregnancy. t a t i o n and v a s c u l a r i t y .  g.  A newly—forming corpus luteum of pregnancy. Ovulation occurred four days previously. The medulla i s to the l e f t .  h.  Granulosa l u t e a l c e l l s i n • a degenerating corpus luteum. Note the honeycomb s t r u c t u r e caused by vacuoles i n most of the cells. One c e l l at top center shows the normal heavy s t a i n ing of most of the granulosa l u t e a l c e l l s during pregnancy.  i.  A scar of a r e c e n t l y - p a s t pregnancy. The brown pigmentation shows up w e l l i n coloured m a t e r i a l . At t h i s stage the scar i s mostly connective t i s s u e with enclosed blood vessels. A f o l l i c l e i s v i s i b l e on the r i g h t , and the c o r t i c a l stroma on the l e f t . A few primary f o l l i c l e s are v i s i b l e around the periphery of the ovary at the top.  sow.  Note the gen-  Note the pigmen-  73.  Y O L U : ME  (mm ) J  mean t  .05  S E  300  0  200  100  Jan n=3  Feb n=ll  Mar n=7  Apr n=5  F i g u r e 1g . S e a s o n a l a l l sows o l d e r Texas. V a l u e s l e v e l , and the :  May n=5  Jun n=10  Jul n=6  Au.£ n=l  Sep  Oct  n=5 (3=5.  Nov  n=19  changes i n s i z e o f o v a r i a n m e d u l l a f o r t h a n two y e a r s c o l l e c t e d i n s o u t h g i v e n a r e mean, s t a n d a r d e r r o r a t the t Eange.  75.  corpora l u t e a of pregnancy or non-pregnancy, scars of pregnancy (= corpora a l b i c a n t i a ) , and non-pregnancy, degenerating f o l l i c l e s , d i f f u s e i n t e r s t i t i a l c e l l s (which i n some pregnant animals take on a l u t e a l appearance),  con-  s i d e r a b l e amounts of connective t i s s u e , and blood v e s s e l s . B r i e f l y , the ovarian changes associated with the cycles of oestrus and pregnancy i n the peccary were as f o l l o w s . primordial f o l l i c l e s developed i n t o  In an oestrus c y c l e many  primary f o l l i c l e s .  Of these, a high  percentage became a t r e t i c and the remainder enlarged i n t o the subadjacent stroma.  There was a high m o r t a l i t y r a t e of f o l l i c l e s throughout the process,  and only 10 to 40 f o l l i c l e s per c y c l e grew to a s i z e greater than the 1 .5 mm diameter t e r t i a r y f o l l i c l e .  Of these, u s u a l l y two, but sometimes three or  one, developed to a diameter greater than 3 mm and ovulated at 4 to 6 mm diameter.  The l a r g e s t f o l l i c l e s found were i n the ovaries of a pen-raised  sow, that had gone through two oestrus cycles while l a c t a t i n g , and was entering a t h i r d oestrus.  just  The f o l l i c l e s were 5.4 mm and 4.8 mm average 3  diameter with volumes of 80.2 and 57.6 .mm . C y c l i n g of new f o l l i c l e s continued even i n pregnant sows.  How-  ever, the f o l l i c l e s seldom reached 3 mm diameter before becoming a t r e t i c .  A  few (one to four) of the large f o l l i c l e s became l u t e i n i z e d and formed accessory corpora l u t e a at any time during pregnancy, though most commonly during the early stages.  L u t e i n i z a t i o n i n these cases occurred i n both ovulated and  unovulated f o l l i c l e s . When f o l l i c l e s ovulated during oestrus, they immediately with l u t e a l t i s s u e whether or not. the sow had been impregnated  filled  (Plate 5 g).  I do not have any d i r e c t evidence of the length of time that the corpus i s maintained i f pregnancy does not occur i n peccaries, but i n pigs i t appears to be 14 days (Corner, 1915, 1921).  These corpora l u t e a of non-pregnancy  (CL-NP) did not a t t a i n a s i z e as l a r g e as corpora l u t e a of pregnancy (CL-P) (see Appendix F, Tables 1 and 2 ) .  Furthermore,  v a s c u l a r i z e d or pigmented as did CL-P degenerated,  they did not become as w e l l  (Plate 5 e and f ) .  Thus, when they  they p e r s i s t e d f o r a r e l a t i v e l y short time, and the scar was  usually d i s t i n g u i s h a b l e from the pigmented v a s c u l a r i z e d scars of  CL-P.  The corpus luteum grew very r a p i d l y during the f i r s t three to four weeks i n pregnant sows ( F i g . 19). the c a l c u l a t e d age of the conceptus  The age of the CL-P was determined from (Appendix C) except at the 0 to 14 day  .7.6..  VOLUME  (mm ) 3  ^_/range mean  1000  -t  SE J05  500 I  CH^JO-14 n=ll  15-45 n=3  60-80 n=8  85-115 n=14  120-term n=l3  F i g u r e 19. Changes i n t h e volume o f t h e corpus l u t e u m o f pregnancy (CL-P) w i t h p r o g r e s s o f g e s t a t i o n p e r i o d .  AGE (d ) ayS  77. stage.  At t h i s stage the conceptus i s too small to l o c a t e r e a d i l y , and  the CL-P and CL-NP are d i f f i c u l t to d i f f e r e n t i a t e .  However, i f the uterus  was over 50 gm, the animal was assumed to be pregnant.  There was l i t t l e  change i n the mean s i z e a f t e r the i n i t i a l r a p i d growth u n t i l the l a s t month before p a r t u r i t i o n when there was a s i g n i f i c a n t increase i n the volume of the CL-P ( F i g . 19). The increase appeared to be caused by hypertrophy of the granulosa l u t e a l c e l l s . The l a r g e s t CL-P i n the paired ovaries f o r which a corresponding conceptus was found ranged from 200 mm^ to 1049 mrrp.  W i s l o c k i (1931) has  described the c y t o l o g i c a l appearance of the corpus luteum of pregnancy. I t has the appearance shown i n P l a t e 5 h". Blood vessels were w e l l e s t a b l i s h e d throughout the corpus, not as i n CL-NP where the l a r g e r vessels were mainly near the periphery.  The granulosa l u t e a l c e l l s became i n c r e a s i n g l y pycnotic  through g e s t a t i o n , so that by term, most of the granulosa l u t e a l c e l l s stained very deeply.  In v i a b l e corpora, the granulosa l u t e a l c e l l s were  generally not vacuolated, or i f so, then the vacuoles were very s m a l l . However, i n non—viable corpora l u t e a , the l u t e a l c e l l s had a honeycombed appearance (Plate 5 h). A f t e r p a r t u r i t i o n , the corpus regressed w i t h i n two weeks to a mean volume of 140 mm^ ( F i g . 20). Shrinkage occurred p r i m a r i l y through l o s s of cytoplasm, and compaction of blood vessels (Plate 5 f and h). The scars of pregnancy were h e a v i l y pigmented and stained brown to tan i n Masson's trichrome s t a i n .  In ovaries which had been f i x e d i n Bouin's  S o l u t i o n and sectioned by hand, the scars also appeared dark brown. Scars of past pregnancy were d i s t i n c t l y v i s i b l e i n ovaries of non—pregnant animals, and with experience could be d i s t i n g u i s h e d from scars of CL-NP.  Scars of degenerate  f o l l i c l e s were a l s o d i s t i n g u i s h e d by t h e i r  lack of pigment and blood v e s s e l s .  In pregnant animals, p a r t i c u l a r l y  those having two corpora i n one 'ovary, the compression  and displacement  of c o r t i c a l s t r u c t u r e s i n the ovary.was extreme, and d i s t i n g u i s h i n g and counting scars became d i f f i c u l t and u n r e l i a b l e . 4.6.3.  The Reproductive Cycle Oestrous Period and Cycle Wide v a r i a t i o n was present i n the l i m i t e d data obtained on  oestrous c y c l e s .  Five determinations of the length of the c y c l e i n one  sow averaged 26 days with a range of S to 42 days.  S i m i l a r l y , four  determinations of the duration of oestrus averaged 5.8 days with a range  .78,.  F i g u r e 20. R e g r e s s i o n of the corpus luteum of pregnancy after parturition.  (CL-P)  79.  of 3 to 9 days.  The frequency of mating of two.young sows cast doubt on  the method f o r determining  oestrus periods f o r some i n d i v i d u a l s ; however,  f o r most adults i t i s probably  valid.  Ovarian s t r u c t u r e s i n d i c a t e d that some, but not a l l , w i l d pecc a r i e s were polyoestral. throughout the year.  CL-NP were found at a l l months  of the year with consecutive scars of past oestrous periods i n many cases. In s e v e r a l sets of o v a r i e s , scars of corpora l u t e a of non-pregnancy of at l e a s t threeigenerations were present covering a period of at l e a s t 2 months.  1/2  I t was p o s s i b l e t h a t these could have been"silent" heats; t h i s  might thus e x p l a i n the f a c t that the animals had not been impregnated.  On  the other hand, i n the c a p t i v e colony, there were several instances of copulation that did not l e a d to pregnancy.  This i s not unexpected on the  basis of information from other species. A 5 1/2 year o l d sow c o l l e c t e d i n February, 1967, s t i l l i n themajor breeding period during the drought, had not had an oestrous cycle f o r at l e a s t 3 months before c o l l e c t i o n . i n October, 1965,  Another sow, 8 1/2 years o l d , c o l l e c t e d  j u s t before the major breeding season during the year of  good range conditions also had not cycled f o r at l e a s t 3 months before c o l l e c tion.  Ovarian f o l l i c l e s were s t i l l c y c l i n g i n these animals, and 19 and  22,  r e s p e c t i v e l y , old'scars of past pregnancy were present i n the paired ovaries. In view- o f j t h e many f a c t o r s that can contribute to f a i l u r e to ovulate, 'these two instances do not c l a r i f y the f i e l d circumstances  that c o n t r o l o v u l a t i o n .  Gestation Period The length of pregnancy of 13 captive peccaries averaged days (range '140 -.147 days, Sx = 0.6). sow;  144.3  Seven .periods were recorded f o r one  they ranged from 141 to 147 days with a'mean fo 144.6  days.  Frequency of Gestation An .intensive e f f o r t was made to determine the i n t e r v a l between p a r t u r i t i o n and post-partum oestrus, and to determine the frequency of f e r t i l i t y of the post-partum oestrus.  Post partum oestrus i s -here defined as an  oestrus occurring w i t h i n two weeks of p a r t u r i t i o n . Sows were presented partum period ("Table 19).  to boars on nine occasions during the post-  Copulation took place on seven of these occasions.  On two of four occasions, when the sow was introduced to the boar on the f i r s t day a f t e r p a r t u r i t i o n , c o p u l a t i o n ensued. /  On both occasions the copulation  Table 19.  Sow UBC 4 (Pc 18D)  I n t e r v a l Ibetween p a r t u r i t i o n and oestrus i n ; pen-reared peccaries  Parturition Date 1D-IV-66 5-X-66 24-IV-66 25-IX-67 25-11-68  30-VII-68  1 st Mating 3-V 17-V 29,30-XI 25,26-IV 4-V 26-IX 2,3-X  7  Days, postpartum  Lactating  Previous opport u n i t y , days postpartum  No Yes Yes No Yes No Yes Yes No Yes Yes  23 37 55,56 1, 2 10 1 7,8 5,8,9,,11, 12 20,21 58,59 5  Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes  No Yes No No Yes No Yes 2,3 Yes, Yes,• 17 Yes Yes,, 3  15-1  No No No No Yes  4 12 21 26 95  Yes Yes Yes Yes No  Yes, Yes Yes Yes Yes  1,4,5,7,8-111  19,21-VIII 27,30-11  UBC 391 (Pc 168)  Fertile  •  22-11-69  27-11  12-X-67  16-X 24-X 2-XI 7-XI  ?  UBC 393  8-VII-68  17-VII 13-VIII 26-VIII  No No No  9 36 49  No No No  Yes,, 2,4,7 Yes Yes  UBC 394  24-VI-68  28-VIII  Yes  65  No  17  Yes  Yes,, 1,2,3,8,11,16,17,20, 22:,24 Yes,, I C1,12,14  10,11  No  Yes,, 2,5  UBC 397  19-1-69  5-II  ?  19-1-69  28,29-1  Yes  81 . plug was l o s t . i n pregnancy.  On f i v e of seven occasions the post-partum mating r e s u l t e d The i n t e r v a l from p a r t u r i t i o n • t o f e r t i l e mating was 5 to  12 days. The frequency of pregnancy of w i l d animals was determined from pregnant animals that showed evidence of e i t h e r l a c t a t i o n or recent scars of previous pregnancies (corpora a l b i c a n t i a ) .  Only four sows, a l l from  south Texas, were c o l l e c t e d that were pregnant and s t i l l l a c t a t i n g (Table 20).  They varied i n post-conception time from 20 to 125 days.  P-10 was  4 months post-conception,- i n d i c a t i n g about 4 1/2 months since p a r t u r i t i o n , and s t i l l l a c t a t i n g .  Several captive sows were s t i l l l a c t a t i n g when the  young were weaned a t 3 months, and one at 3.7 months.  Most of these captives  were pregnant while s t i l l l a c t a t i n g . An a d d i t i o n a l eight south Texas sows were found to have gone from one pregnancy i n t o the next, e i t h e r d i r e c t l y , or f i r s t through an i n f e r t i l e oestrus (Table 20). This was determined from ovarian a n a l y s i s .  Scars  more recent than 4 to 5 months are s t i l l regressing, and CL-NP and CL-P scars are usually d i s t i n g u i s h a b l e .  In a d d i t i o n , three sows that were l i v e -  trapped with young had produced young i n both spring and f a l l at i n t e r v a l s of 6 months (2) and 5 1/2 months ( l ) i n 1965. Only two of the west Texas animals showed signs of possible consecutive pregnancies. Both of these were i n preimplantation stages so i t was not p a s s i b l e to determine i f the corpora l u t e a were corpora of pregnancy o r non-pregnancy. 4.6.4. Maturation The youngest age at conception was 11.3 months and the youngest animal to copulate was a 10.2-month o l d , 37 pound female (Table 21). Both of these were pen-reared. The ovarian analysis'showed that f o l l i c l e s began c y c l i n g by 7 months i n one south Texas female, and the f i r s t corpora l u t e a of nonpregnancy scars were backdated to an age of about 7 1/2 months i n a 10-month o l d g i l t . was 24 months o l d .  The youngest pregnant animal c o l l e c t e d "in south Texas  Table 20.  Incidence of consecutive pregnancies i n south and west Texas peccaries.  South Texas P-10 P-14  Post-conception Age  Conception date  Evidence of prev. preg."*  1 1  125-128 days 46 days  15-XII-64 6-V-65  5 yr  2  20- 35 days  7-VI-65 1-VIII-65  S l i g h t amount l a c t a t i o n Lactation; CL-P scar 2-3 mo. o l d ; CL-NP scar 2 mo. o l d Not l a c t a t i o n ; CL-P scar; no CLNP scar Lactating; CL-P scars; no CL-NP scar; d i r e c t preg Not l a c t a t i n g ; CL-P scar; No CL-NP scar Not l a c t a t i n g ; CL-P scars CL-NP scars Not l a c t a t i n g ; CL-P scars Not l a c t a t i n g ; CL-P scars 4 mo. o l d Not l a c t a t i n g ; CL-P 4 mo. o l d Not l a c t a t i n g ; CL-P scars no CL-NP scars Not l a c t a t i n g ; CL-P scars no CL-NP scars L a c t a t i n g ; caught 8 wk. o l d young; CL-P scars; Direct preg preg.  Date  Age  of Foetuses  21-IV-65 27-VI-65  8 yr 6 yr  No.  P-21  2-VII-65  P-31  23-VIII-65  3 1/2 y r  1  20- 25 days  P-32  27-VIII-65  6.5 y r  2  88- 93 days  29-V-65  P-35  15-IX-65  5.7 y r  2  115-121 days  20-V-65  P-SO P-81 P-9S  7-II-66 18-V-66 15-VI-66 8-VIII-66  2 2 2 1  82- 87 130-137 89 108-113  days days days days  16-XI-65 6-1-66 18-111-66 19-111-66  P-III- • P-130  6.0 10.0 8.2 7.2  yr yr yr yr  22-V-67  (2 y)  2  50  days  1-Iv-67  15-VI-67  (5 y)  2  52- 60 days  20-IV-67  West Texas BG-6-43  10-XII-66  4.8 y r  ?  preimplant  XI-66  BG-6-52  12-XII-66  5.4 yr  ?  preimplant  XI-66  P-140  —  —  Note:  —  —  —  —  —  Not l a c t a t i n g ; t h i s i s 1st c y c l e since p a r t u r i t i o n ; p o s s i b l y CLNP? Not l a c t a t i n g ; 1st or 2nd c y c l e since p a r t u r i t i o n ; poss. CL-NP?  ,  * CL-P scars = CL-P degenerating but l e s s than three to four months o l d .  03  83.  Table 21.  Behavioural maturation of pen-reared peccaries.  Animal No. UBO -4 (Pc 180J UBC 391 (Pc 168) UBC 393 UBC 394 UBC 395 UBC 397 UBC 401 (Pc 181)  Age from which Boar Available. 10.0 mo. 11.1 mo. 7.9 mo. 7.9 mo. 11 .4 mp. 9.2 mo. 14.6 mo.  Age at First Copulation 10.2 mo. 11.7 mo. 12.6 mo. 11.3 mo. 11.4 mo. 11.3 mo. 14.9 mo.  Age at First Conception 12.5 mo 13.5 mo. 16.6 mo. 16.3 mo. 11.3 15.1  She was about 52 days post-conception and had i n February.  mo. mo.  Age at First Parturition 17.4 mo. 18.4 mo. 21.2 mo. 20.9 mo. 16.1  mo.  Length of First Gestation. 144 days 146 days 144 days 140 days 143 days  conceived at about 2,2 months  Of eight females 12 to 22 months o l d , only one had scars of  pregnancy i n the o v a r i e s .  She would have conceived at 16 months o l d i n  January during a minor, drought.  The ovaries of three g i l t s c o l l e c t e d during  good range conditions and four g i l t s c o l l e c t e d during the severe drought, a l l 12 to 18 months o l d , showed no evidence of recent oestruses.  In a d d i t i o n ,  the ovaries of two 2—year o l d g i l t s c o l l e c t e d l a t e ' i n the drought showed no evidence of recent o v u l a t i o n s .  A l l other animals over 2 years o l d had been  pregnant before. Maturation of the west Texas females showed the same retarded pattern as the south Texas females.  When compared with the captive animals, the youngest  female with f o l l i c l e s l a r g e r than 1.5 mm was about 8 months o l d , and the youngest pregnant animal c o l l e c t e d , about 3 months through g e s t a t i o n , was 24 months old.  Four other sows between 24 and 28 months had produced young 2 t o 4  months e a r l i e r . months o l d . collected  They had a l l conceived during winter when they were about 16  However, none of the three g i l t s between 12 and 18 months o l d , during the f a l l hunt, showed ovarian evidence of pregnancy, and  none of the 11 females 12 to 22 months o l d was reported pregnant by the hunters. 4.6.5.  Senility Five sows older than 12 years were c o l l e c t e d , the oldest 15 years  old.  Three of these were pregnant; the oldest two (15 and 14 years) with  twin foetuses, and a 12 year o l d with one foetus. each ovulated two ova.  These three animals had  The other two sows (13 and 12 years) each had three  new corpora l u t e a at the preimplantation stage.  The 12 year old's ovaries  84. contained large amounts of connective t i s s u e and she had gone through two oestrus cycles without becoming pregnant, although she had been pregnant more than 4 or 5 months before.  Ovaries from two west Texas sows estimated  at 9 years or older were c o l l e c t e d . only one foetus.  One of the sows was pregnant, but had  The few scars present suggest that she had been ovulating  only one ovum per oestrus f o r a considerable time.  The other had two CL-NP  and had gone through 3 oestrus c y c l e s , p r i o r to the present one, since she had been pregnant. 4.6.6.  Breeding  season  Although sows were found at various stages of pregnancy at a l l months of the year, there was a major breeding season f o r the w i l d animals. In south Texas the peak conception time, determined by backdating from foetus s i z e was during early winter with a secondary conception period i n spring (Fig.21). Over the three years of the study there were v a r i a t i o n s i n the exact time of peak p a r t u r i t i o n .  During l a t e 1964, minor drought  con-  d i t i o n s p r e v a i l e d , and sows conceived i n l a t e January, February and March. This brought a peak p a r t u r i t i o n i n May and June ( F i g . 21) although f i e l d observations showed the peak i n June and July ( F i g . 22).  Many animals con-  ceived i n l a t e s p r i n g , i n c l u d i n g immediate rebreeding of 40% of the sows that had already produced young that spring. p a r t u r i t i o n i n l a t e f a l l and winter.  There was another minor peak i n  In 1965-66 conceptions started i n  December and peaked i n January and, because of good range c o n d i t i o n s , most of the adult sows conceived.  This e a r l i e r conception peak resulted i n p a r t u r i -  t i o n peaking e a r l i e r , i h A p r i l ( F i g . 21 and 22).  Conceptions occurred again  i n the spring, but range conditions became very poor over the summer and lack of r a i n r e s u l t e d i n almost no forage production i n the f a l l .  Conse-  quently, although there was a minor p a r t u r i t i o n peak i n September ( F i g . 22), s u r v i v a l of young was p r a c t i c a l l y n i l .  Coincident with drought c o n d i t i o n s ,  there were p r a c t i c a l l y no conceptions during the summer of 1966,  consequently  almost no newborn young were seen i n the f i e l d from October u n t i l May,  1967.  Range conditions remained poor, and conceptions d i d not occur u n t i l December, 1966 and only a small p o r t i o n of the sows conceived during January, February, and March.  The peak i n p a r t u r i t i o n , although only minor, occurred i n A p r i l  or May, although f i e l d observations showed the peak i n May and June. a few young were born during the spring of 1967, s u r v i v a l was poor. ceptions were found to occur during the summer of 1967.  Although No con-  Reproductive Index (Foetuses/lOO adult  9)  Figure 21% Seasonal changes i n the breeding a c t i v i t y of adult female peccaries i n south Texas.  CD cn  Figure 22.  Approximate birthmonth of young peccaries on the Welder Refuge and the King Ranch determined from p e r i o d i c observations and backdating to the birthmonth of young l e s s than 6 months o l d . The bars represent the percent of that years' young born during that month. The sample s i z e , n, includes some recounts of i n d i v i d u a l s . Observations were made during the months underlined.  PER CENT OF YEAR'S YOUNG BORN IN MONTH  '•aa,  88.  In west Texas, the breeding season also appeared to extend out the year.  through-  However, p a r t u r i t i o n peaked during the l a t e spring and summer  months ( F i g . 23). One of two adult sows c o l l e c t e d i n January, 1966,on the Watson Ranch was l e s s than 3 weeks post—conception. c o l l e c t e d i n June, 1966.  Three adult sows were  One had given b i r t h the night before, another had  produced young l e s s than a week before, and the t h i r d was three months postconception.  Another adult c o l l e c t e d i n September, 1966, was l a c t a t i n g , and  had a 3-month o l d young with i t .  Thus, p a r t u r i t i o n occurred i n May and June,  and conceptions took place between e a r l y January and l a t e March. In 1965, there was r e l a t i v e l y l i t t l e r a i n f a l l , and no evidence of pregnancy i n the November-December Black Gap c o l l e c t i o n .  In a d d i t i o n , none  of the sows even showed ovarian evidence of recent o v u l a t i o n s .  The Watson  Ranch animals,- as shown, d i d not mate u n t i l January to March, 1966.  However,  a f t e r good summer and f a l l r a i n s and improved range conditions i n 1966, the November-December Black Gap c o l l e c t i o n showed 25% of the adult sows pregnant. One of these sows was approaching nancy.  term, and the other three were i n earfl-y^preg—  In a d d i t i o n , three other sows had ovulated 2 to 3 weeks p r e v i o u s l y , but  had probably not conceived. Observations of free-ranging peccaries on the Watson Ranch v e r i f y • the breeding season determined by the reproductive t r a c t a n a l y s i s . Backdating to.the b i r t h date of animals l e s s than 1/2 year o l d showed a complete p i c t u r e only f o r 1966.  Eighty—two percent of the 17 young observed were born  in May and June, corresponding with a January—February  mating period.  Other  young were born i n March (12%) and October ( 6 % ) . A ..comparison of t h i s s o r t assumes that m o r t a l i t y r a t e remains r e l a t i v e l y constant through the year.  Be—"  cause m o r t a l i t y of young born i n l a t e f a l l or winter was probably higher, the proportion of young born at that time was probably under-represented  in„Fig.23.  However, since observations and c o l l e c t i o n s were made p e r i o d i c a l l y through the year any strong bias should be detected.  Observations were made during only  parts of 1965 and 1967 and i t was not p o s s i b l e to determine the percentjof young born at monthly i n t e r v a l s .  In 1965 many young were born i n the summer  and f a l l . On the Black Gap area, hunters reported 17 young between 3 and 6 months o l d , but no red young (<• 3 months) i n Nov.-Dec, 1965.  In contrast, i n  the November-December 1966 hunt, they reported 11 red young and eight 3-te month olds.  These data do not i n d i c a t e the strength of the spring increment of young  i n e i t h e r year.  I t appears that i n 1965, the b i r t h s were concentrated i n  89;.  75  50  O  0 o  12%  CD  PH  3  4  3  KJTJ M J' J' A'S' o" N' DI J' F'M' A'M' J' J' A'S" O'N' Dl J ' F'M' A'M'J ' J ' A'S' 1965  (N = 10)  Figure.-|§'..  1966  (N = 17)  1967 ( N = 3)  Birthmonth of young peccaries i n west Texas. See legend f o r Figure 21.  90. early summer, and i n 1966, with b e t t e r range conditions over a longer period of time, b i r t h s were s c a t t e r e d over a longer period throughout summer and e a r l y fall.  I t i s l i k e l y that the large number of red young present i n the f a l l of  1966 represented a s u c c e s s f u l second breeding during that year. 4.6.7.  L i t t e r Size The average l i t t e r s i z e throughout the study was 1.81  Table 22 l i s t s the d i s t r i b u t i o n frequency of l i t t e r s i z e .  foetuses.  One of the w i l d  sows with three v i a b l e foetuses had a mummified foetus present; thus four embryos had implanted.  There were s l i g h t d i f f e r e n c e s i n frequency of m u l t i p l e  l i t t e r s between w i l d and pen-born l i t t e r s . Table 22.  Percentate frequency of l i t t e r s i z e i n peccaries. Values are percentages  Area  No. foetuses 'I  South Texas w i l d South Texas pen-born Arizona w i l d Arizona pen-born  30 28 17 4  P r o b a b i l i t y of s i m i l a r i t y  ^  3  q  68 56 50 84  5 17 33 8  4  n  34 —\ n.s. — 18 1 P < .1 24 ] P = .25' 25  P = .5  Captive animals produced 17% t r i p l e t s whereas w i l d sows had 5% t r i p l e t s i n utero.  However, t r i p l e t s were seen only once i n the w i l d and these were l e s s  than two days o l d . 4.7. 4.7.1.  Productivity Ovulation Incidence Ovulation incidence, the number of ova shed at oestrus, was  determined  from counts of corpora l u t e a of pregnancy, or from the most recent scars of pregnancy or non-pregnancy. only one ovum.  I t was assumed that each corpus luteum represented  Polyovular f o l l i c l e s were not uncommon i n the ovaries, but none  l a r g e r than 2.5 mm diameter was observed.  Brambell (1956) i n d i c a t e s that  polyovular f o l l i c l e s seldom mature. Although older sows did tend to have a s l i g h t l y higher o v u l a t i o n incidence than young sows, there was no s i g n i f i c a n t change with age (Table 23).  The mean o v u l a t i o n incidence of a l l sows 2 years and older was  ova/oestrus i n south Texas, and 2.0 ova/oestrus i n west Texas. was not s i g n i f i c a n t .  2.2  The d i f f e r e n c e  That i s , when o v u l a t i o n occurred, sows from both regions  to  Table 23.  Age-specific pregnancy, ovulation and implantation incidence of south and west Texas, and pen—reared peccaries. Notes:  a= t o t a l number of ovulations at the most recent ovulation; determined from CL-P, CL-NP, and corpora albicantia/number of animals possessing evidence of ovulation = average number of ovulations per animal (range). b=total number of foetuses found/number of sows possessing v i s i b l e foetuses = foetuses per pregnancy (range), i . e . implantation incidence. c=numbers r e f e r to d i f f e r e n c e between ovulation and implantation incidence, and the degree of s i g n i f i c a n c e .  Age  Area  Proportion  1-1 .9  S.Tx. W.Tx. Capt.  0/7 0/3 8/8  0 0 100  1/7 0/3  2-2.9  S.Tx. W.Tx. Capt.  2/7 2/14 4/5  29 14 80  3/7 10/,14 1/5  3-3.9  S.Tx. W.Tx. Capt'.  5/7 0/2 1/1  71 0 100  2/7 2/2  4-4.9  S.Tx. W.Tx. Capt.  3/4 2/5 2/2  75 40 100  1/4 3/5  25 60  8/4 10/5 3/1  2.0 2.0 3.0  (2) (2) (3)  5-5.9  S.Tx. W.Tx.  8/11 1/2  73 50  3/11 1/2  27 50  23/10 4/2  2.3 2.0  (2-3) (2)  6-6.9  S.Tx. W.Tx.  5/6 0/2  83 0  1/6 2/2  17 100  11/6 2/1  1 .8 (1 .3) 2.0 [2)  8/5 0/0  1 .6 (1-2) •2, P=n.5.  7-7.9  S.Tx.  2/2  100  0/2  •  4/2  2.0  [2)  3/2  1 .5 (0-2) .5, P<.5  8-8.9  S.Tx.  4/5  80  1/5  20  8/4  2.0  (2)  6/4  1 .5 (1-2) •5, n.s.  9-9.9  S.Tx. W.Tx.  5/6 83 1/2 .- 50  1/6 1/2  17 50  16/6 3/2  2.7 (2-4) 1 .5 (1-2)  7/4 1/1  1 .8 (1-3) • 9, n.s., + 1 resorb.,1 .5, n.s. 1 .0 ( 0  10-15  S.Tx.  7/8  1/8  12  19/8  2.4  (2-3)  9/5  1 .8 (1-2) .6, n.s., + 1 resorb.  7+  S.Tx. Preg.sows  3D/13  2.3  4/2 5/2  2.0 2.5  (2) (2-3)  117/54 51/26  2.2 2.0  (1-4) (1-3)  UnKn.Ad. S.Tx. 1/2 W.Tx. 0/2 Total 2+ y r s . S.Xx. 42/58 W.Tx. 6/29  88  50 0 72 21  Proportion  1/2  15 0  43', 71 20 29 100  50  -100 2/2-'14/58 21/29  24 72  Ovulation Incidence 2/1 2.0 (2) 0/0 2/1 2.0 (1)  Foetuses per  —— —  0/0 16/9  6 virgin 3 virgin  Comments  1 .8 (1-2)  10/5 23/12 7/3  2.0 (2) 1 .9 (1-2) 2.3 (2-3)  4/2 3/2 8/5  2.0 (2) 2 virgin 1 .5 (1-2) 2 v i r g i n 1 .6 (1-2)  14/7 4/2  2.0 2.0  (1-3) (2)  5/3 0/0  1 .7 (1-2) .33 , P<.5  4/2  2.0  (1-3)  4/2 2/1 6/2  2.0 2.0 3.0  (2) (2) (3)  15/7 0/0  2.3  (2-3) .14  22/13 1.7  0 0  P<.4  .6, P< .D1  o/o o/o 61/34 1.8 (1-3) .38, P <C .002 6/4 1 .5 (1-2) .46, P = n.s.  abori  93. produced abouth the same number of ova. Since there was no d i f f e r e n c e i n ovulation incidence between south and west Texas, a change i n ovulation incidence i n south Texas from good r a i n f a l l to poor r a i n f a l l periods was not expected, and t h i s proved the case. Ovulation incidence i n a l l adult sows i n the good r a i n f a l l period was 2.17 ova/oestrus,  .10.  and i n the poor r a i n f a l l period 2.2 + .12 ova/oestrus (n.s., P = .5).  In the pregnant sows, the incidence was 2.13 2.14  +  ova/oestrus i n the good period, and  i n the poor (Table 24).  4.7.2.  Implantation  Incidence  I t appeared that the period between ovulation and implantation was time of greatest i n t r a - u t e r i n e m o r t a l i t y .  the  Average losses of embryos p r i o r to  implantation were determined from 34 sows i n the post-implantation stage of pregnancy by s u b t r a c t i n g the number of foetuses from the number of corpora l u t e a of pregnancy.  These '.lo.sses t o t a l l e d 17.5%  (P< .002) .over the study  period i n a l l south Texas sows two years and older (Table 23).  The l o s s of  embryos before implantation i n 21 sows l e s s than s i x years o l d was not s i g n i f i c a n t , but i n 13 animals over 7 years, the r a t e of f a i l u r e to implant was  26.7%  (P < .01) (Table 23). Only three cases of f o e t a l m o r t a l i t y were found i n 42 south Texas sows examined a f t e r the "implantation" stage.  One of these was mummification  of one of four foetuses, a second was r e s o r p t i o n of one of three foetuses, and the t h i r d was abortion of a l l foetuses. In west Texas, only four sows with foetuses were c o l l e c t e d .  The  sample i s too small for;''a r e a l i s t i c comparison with the south Texas c o l l e c t i o n , but 25% of the ova f a i l e d to "implant". A s l i g h t l y b e t t e r i n d i c a t i o n of the e f f e c t of adverse c l i m a t i c cond i t i o n s on implantation was a v a i l a b l e i n comparison of the implantation r a t e i n the moist and drought periods i n south Texas.  The time at conception  was  used to determine which period the implantation occurred i n , and only the moist period from June, 1965 to June, 1966, 1966 to August, 1967 were used.  and the drought period from J u l y ,  During the period of good range conditions the  ovulation incidence of 28 sows with foetuses was 2.17 implantation incidence. 1.88  + .13 foetuses/sow.  + .10 ova/sow, and the  In the drought period i n only  6 sows, o v u l a t i o n Incidence was 2.2 + .12 ova/sow and the implantation incidence was 1.67  + .21 foetuses/sow.  The d i f f e r e n c e s i n ovulation and implantation  94.  Table 24. Period  Seasonal ovulation and implantation incidences, and reproduct i v e index i n south Texas peccaries, 1965 to 1967.  Proportion Corpora Lutea pregnant no"! n no/100 Jo no! n Preg. ad. F. F. c  1965 Jan-Mar100 Apr-Jun100 Jul-Sep S3 Oct-Nov 25 Total 81  1 1 10 10 5 6 1 4 17 21  12 16 4 d 48  1966 Jan-Mar100 Apr-JunlOO Jul-Sep 17 Oct-Dec 33 Total 71  10 4 1 1 16  13 1  1967 Jan-Mar 40 Apr-Jun100 Jul-Sep 40 Oct-Dec T o t a l 60  d  1 6  10 4 6 3 23  -3  17  2 5 2  5 5 5 0 9 15  8 4  d  12  6 7 2 7 22  200 229 200 229 218  200 229 166 57 177  9 15 3 12 39  6 1 1 2 9  217 100  217 100  11 1  150 189  50 134  3  3 2  267 200  107 200  3 4  —  —  H  d  T o t a l , 1965--1967 H Jan-Mar 79 11 14 3 3 Apr-Jun100 19 19 21 7 15 4 Jul-Sep 47 Oct-Dec 29 2 7 d T o t a l 71 40 56 8 1 d  d  1 9  d  Implantation Incidence no. foetus/ foetus 100 CL  -  —  — —  —  -  5  240  144  7  15 10 2 9 34  220 210 200 211 214  174 210 94 61 152  23 20 3 15 61  Reproductive Index Foetuses/100 ad. sows quarterly h a l f - y e a r l y  75 94 75 92 87 x =  150 215 125 52 154  85 100  184 100  100 88 X  118  50 100  54 200  -  -50  —  x = 116 = 301/yeai  172 33 = 205/year  118  —  70 y = ioo 74 95 75 94 80  x = 185  X"  129 200 71 57 = 122  0 = 118/year  163 77 = 24£)/-year  T o t a l Moist P e r i o d 16 213 176 27 87 X 153 83 19 23 34 = 288 Total Drought P e r i o d 7 214 103 10 77 x 79 = 151 48 11 23 15° Note : a = number backdated to month of conception = ovulation incidence. b = determined f o r month of conception c = determined by: °/o pregnant when c o l l e c t e d X°/o of CL represented by foetuses conceived during that month X no. of CL per preg. sow. d = included i n the f i g u r e are some animals c o l l e c t e d i n early pregnancy and embryos were not found i n the uterus. e = moist period i s period of high p r e c i p i t a t i o n and good range condi t i o n s , J u l y , 1965 to June, 1966 on t h i s t a b l e ; the drought period extends from J u l y , 1966 to Aug. '67, range conditions poor. 0  d  e  95.  incidence between the two periods were not s i g n i f i c a n t . f a i l u r e r a t e i n the moist period was period was  .53 + .34 ova/sow.  The  implantation  .29 + .11 ova/sow and i n the drought  Because there were only s i x sows c o l l e c t e d  during the drought that were i n post-implantation pregnancy, the variance i s high during that period, and the d i f f e r e n c e i s not s i g n i f i c a n t . 4.7.3.  Ovulation and Implantation Rates The proportion of sows i n which there were degenerating  CL-P  as  w e l l as f u n c t i o n a l CL-P was greater i n south Texas during the period of good r a i n f a l l than i n e i t h e r the drought period i n south Texas, ;..or i n more a r i d west Texas (Table 25).  The sample obtained during the mild drought i n  the spring of 1965 i s not comparable with the other two south Texas sample periods because i t was a short sample-period taken during a peak p a r t u r i t i o n and breeding period.  The south Texas c o l l e c t i o n during good range conditions  showed that 60/> of the pregnant sows had ovarian scars of r e c e n t l y past D  preg-  nancy, whereas only 33% of the pregnant sows c o l l e c t e d during the period of drought had r e c e n t l y produced young.  Of the sows c o l l e c t e d during the period  of good range conditions, 41% remated, and only 9% remated during the drought conditions.  Therefore, ovulation and implantation rates during the period of  good range conditions would be 1.41 incidences.  times the ovulation and implantation  During the drought conditions, the rates would be 1.09  times  the o v u l a t i o n and implantation incidences. The data f o r west Texas animals were c o l l e c t e d during such a short period that any inferences of rates would be premature. 4.7.4.  P r o d u c t i v i t y of age classes Young w i l d peccaries seldom produce a l i t t e r before they are two  years o l d (Table 23), and since I had no measure of the number of young produced by subadults  ( e s s e n t i a l l y f u l l grown, but the majority of the cohort  have not produced young, Hanson, 1963:8), p r o d u c t i v i t y of t h i s age c l a s s must be disregarded.  This i s not s t r i c t l y accurate, as a l l of the pen-reared animals  had produced a l i t t e r by two years, and the average l i t t e r s i z e was  1.8.  The r e l a t i v e c o n t r i b u t i o n by older animals did not change s i g —  4  n i f i c a n t l y with age c l a s s , but did show a trend f o r 4-and 5-year olds to be most productive (Table 26).  The c o n t r i b u t i o n of each age c l a s s to the pro-  duction of each gestation period was determined from the proportion of that  Table 25.  Proportion of adult sows showing evidence of consecutive pregnancies i n south Texas and west Texas during drought and good r a i n f a l l periods. S o u t h Mild drought  °/o of sows known pregn.  3  good pptn'  T e x a s drought  3  Wes, t 0  Total  T e x a s  Moist (1966)  dry(1965) • (0/13)  Total  92  (11/12)  71  (17/24)  26 (6/23)  58  (34/59)  25 (4/16)  73  (8/11)  60  (9/l5)  33 (2/6)  59  (19/32)  • (0/4)  f  •  o (d/4)  % t o t a l with consec. pregn, 67  (8/12)  41  (9/22)  33  (19/57)  • (0/4)  f  0  D (0/29)  °/o pregn. with recent CL-P scars  b c d e f  —  B  9 (2/23)  25 (4/29)  good range conditions, June, 1965 to June, 1966. severe drought conditions July, 1966 to August, 1967. c o l l e c t i o n s p r i m a r i l y i n November-December and not comparable to south Texas c o l l e c t i o n s , two p a i r of ovaries not examined. two sows i n preimplantation stage and pregnancy not c e r t a i n .  f  97. age c l a s s i n the population (Table 10) and the reproductive index of each age c l a s s (Table 26).  I r r e g u l a r i t i e s i n the proportion of young contributed  by each age c l a s s are caused by small sample s i z e .  However, the older age  classes contributed a high proportion of the young to the population.  Two  year olds, by v i r t u e of t h e i r abundance i n the population, and 5 year olds, because of t h e i r higher p r o d u c t i v i t y , contributed the most to the population. Larger sample s i z e ' would probably show a better d i s t r i b u t i o n of c o n t r i b u t i o n among the younger age c l a s s e s . Because of the small proportion of pregnant sows i n the west Texas c o l l e c t i o n s (Table 20), i t was impossible to determine the c o n t r i b u t i o n of young by each age c l a s s . absent,"  the c o n t r i b u t i o n by the younger age classes assumes more importance.  Table 26. Age Class  However, since the older age classes were v i r t u a l l y  Age c l a s s p r o d u c t i v i t y of south Texas peccaries.  Sample Size  Young/ °/o of ad. pregnancy population  1 yr 2 3 4 5 6 7 7+  8 7 7 4 9 6 2 20 63  4.7.5.  Gross^Net P r o d u c t i v i t y  7  2 1 .7 2.0 2.25 1 .6 1 .5 1 .7  29 12 8 ,7 12 9 3 22  Young/100 ad. sows / gestation —  —  —  24.0 13.5 14.0 27.0 14.4 4.5 37.4 134.8  contribution of age c l a s s —  —  —  18 10 10 20 11 4 28 101  The reproductive index (Table 24) was taken as a measure of gross p r o d u c t i v i t y during a three month period.  For p r a c t i c a l reasons, the gross  p r o d u c t i v i t y f o r a year was taken as the average during the major reproductive period plus the average during the minor reproductive period. Gross produ c t i v i t y during 1965 was 301 young per 100 adult sows based on 21 sows. 1966 i t was  During  205 young per 100 adult sows based on 23 sows; and, i n 1967,118  young per 100 adult sows based on 15 sows (Table 24).  These data represent  f l u c t u a t i o n s of 25/o above and 50°/o below the mean during the 3 years of the c  study.  The 1967 estimate i s minimal because c o l l e c t i o n s were not made during  the l a s t four months of the year.  However, since none of the sows c o l l e c t e d  p r i o r to termination of the f i e l d work i n August would have reached term during the f a l l , and any sows breeding i n September or l a t e r would have reached term i n the next year, the c o n t r i b u t i o n from these four months would have been small.  98. During the period of good range conditions, the productivity was 288 foetuses/100 adult sows and only 151. foetuses/100 adult sows during drought conditions (Table 24).  The gross productivity of the penned animals  was 425 young/100 adult sows (n = 7). between production  the  Thus, there was  a marked  discrepancy  of young under r e l a t i v e l y " i d e a l " conditions and that of  even the best f i e l d conditions encountered. Net productivity was  taken as the proportion of young at heel  compared to the number of adult females observed.  The age r a t i o and  sex  r a t i o data were used to determine the proportion of the observed animals which were adult females.  Table 27 shows the monthly and quarterly sightings  of three age classes of young per 100 adult sows.  Because of the overlap of  c l a s s i f i c a t i o n into age classes, the r e s u l t s must be treated with some reservation. 1965,  However, the trends are s t i l l evident. Survival of young in early  the end of the minor drought, was low.  neonatal period was  quite high in early 1966  favourable winter.  The apparently  misleading  Survival of red young past the following the exceptionally  high s u r v i v a l of red young in 1967  is  because most of these were seen within a week or so of b i r t h .  Trapping data i n t h i s study showed that an average of 29%  of the south  Texas population over 1 year old were in the 1-to 2-year old group.  Using  the age r a t i o and sex r a t i o data, t h i s would equal a net productivity of 53 animals per 100 adult sows. population  The less than -1™year olds were 44% of the adult  and equalled net productivity of 81 young per 100 adult sows.  By  comparison neonatal mortality of pen-reared l i t t e r s resulted in a net product i v i t y of 325 young per 100 adult sows.  There was  no mortality of pen-reared  young a f t e r the i n i t i a l neonatal death of 24% of the young. Data f o r West Texas are meagre and the best estimate of product i v i t y were the 1:to 2 year olds.  These comprised 25% of the adult  and indicated productivity of 45 animals per 100 adult sows.  population,  Table 2 7 .  P r o p o r t i o n o f young animals observed i n p o p u l a t i o n and q u a r t e r l y i n t e r v a l s . No  Period  No. adults > 1 y r .  at monthly  of  young/100  ad.F.  Number per  1 0 0 adult  Red  half-grown j u v e n i l e Red half- juvenile 3 mo. 6 — 12 mcjj young grown  0  young mo.  - 3  females  quarterly  1965  Jan Feb Mar Apr May June July Aug Sep •ct Nov Dec  19  3 7 . 9  .98  .19 2 . 5  15.6  9 9 . 4  100  5.1  2 8 .  7 9 . 4  128^  2.1  2 6 . 2  54..1  3 6 ^  3 5 . 6  7 . 2  7 1 . 3  2 7 ^  29 68  3 7 . 6  1 5 . 2  123  6 . 2  2 5 . 2  1 8 . 7  0  2 6 . 5  5 1 . 6  0  2 1 .  4 9 . 2  9 .  78 73,  .  13 C  2 5  C  2 1 . 6  83.1  9 . 4  2 2 . 7  53.1  1 2 . 4  23.1  3 3 . 9  1 8 . 9  4 5 . 9  2 8 . 5  6 . 6  4 4 . 4  3 1 . 3  3 3 . 4  2 2 . 7  2 0 . 7  4 9 . 2  2 2 . 8  50  4 4 . 8  2 6 . 3  0  9  5 . 6  0  0  2 8 . 5  0  4 1 . 4  0  0  8 5 . 4  1966  Jan Feb Mar Apr May June July Aug Sep Oct Nov Dec  2 0 . 4  3 0 . 7  201  4 0 . 8  6 . 8  5 7 . 5  126  1 4 . 2  3 . 9  2 6 . 3  54  6 1 . 7  9 . 4  1 4 . 2  78  23.1  4 5 . 8  3 9 . 3  83 58  1 9 . 2  3 7 . 6  1 2 . 5  2 2 . 2  6 6 . 2  2 6 . 6  66  31.1  2 7 . 2  23.1  1 2 . 8  5 3 . 8  2 0 . 4 3 0 . 6  100 134  7 . 4  3 6 . 3  105  9 . 6  8 7 . 7  56.1  104°  2 . 4  2 9 . 6  5 1 . 7  9 3  C  0  5 . 5  1 4 3 . 2  1 1 2  C  0  1 1 . 4  5 9 . 4  0  4 . 2  4 6 . 9  6 . 6  ,1967  Jan Feb Mar Apr May June July Aug Sep Oct Note:  60 4 2 ^  0  4 8 . 7  84  1 8 . 3  0  0  3 0 . 4  289 64  4 3 . 4  0  2 1 . 3  0  0  132  5 2 . 4  12.1  3 1 .  0  0  3 3 . 9  3 9 . 3  7 . 7  86.1  0  2 5 . 9  2 0 . 8  0  0 1 3  U  0  0  1 9 . 7  b = o b s e r v a t i o n o n l y on K i n g Ranch c = o b s e r v a t i o n o n l y on Welder Refuge a = q u a r t e r l y average determined from cummulative t o t a l s f o r the q u a r t e r e.g. Jan-Mar, 1 9 6 5 , 2 2 5 a d u l t s o b s e r v e d . The f i g u r e i s based on the number o f a d u l t sows g r e a t e r than 2 y e a r s o l d by s u b t r a c t i n g males ( 4 5 % ) and 1 to 2 y e a r o l d s ( 2 9 % i ) from the number o f a d u l t s and s u b a d u l t s observed.  100. 5.  DISCUSSION The foregoing data show that body condition, growth and reproductive  activity  of the c o l l a r e d peccary i n Texas vary considerably with d i f f e r i n g  c l i m a t i c conditions.  On a r i d land ranges, as those on my Texas study areas  were, a few inches change i n annual r a i n f a l l can represent a large percentage deviation from the normal.  The r e s u l t i n g i n f l u e n c e of changes i n r a i n f a l l  on vegetation and animals can be profound as shown by studies by Wallmo (1957), Box (1960), Chamrad and Box (1965) and Harper (1969) on plants and White (1966), Marburger and Thomas (1965), Newsome (1966b), Newsome et a l . , (1967), and Ealey and Main ( 1 9 6 7 ) ,  Qn  animals.  S a d l e i r (1969:105) stated that i t i s academic to seperate the e f f e c t s of climate and n u t r i t i o n since climate so c l o s e l y controls the food supply.  Even temporary shortages of r a i n f a l l cause marked decreases  i n the quantity of green forbs and grasses a v a i l a b l e , but j u s t as importantly there i s an accompanying decrease i n q u a l i t y of the vegetation as i t d r i e s out (.Sampson, 1952; M i l l e r ,  1966).  Conversely, increases i n r a i n f a l l ,  p a r t i c u l a r l y a f t e r a drought, cause immediate increases i n plant growth i f temperature i s favourable (Box, 1961; Harper, 1969).  The increase i n  n u t r i e n t q u a l i t y of plant material during e a r l y growth, and decrease during hot and cold dry periods has been w e l l documented (Sampson, 1952; McLean and T i s d a l e , 1960).  These changes have been demonstrated to occur on the  ranges supporting the '....  populations of peccaries studied (Box, 1961).  For these reasons I have equated high r a i n f a l l l e v e l s with good range cond i t i o n s , and also the converse, p a r t i c u l a r l y since i t was more p r a c t i c a l to make use of r a i n f a l l data than to attempt an a n a l y s i s and i n t e r p r e t a t i o n of changes i n the vegetation i t s e l f . Stomach sample a n a l y s i s , providing information on forage class.u t i l i z a t i o n , showed that peccaries are o p p o r t u n i s t i c feeders and t h e i r diet through the year r e f l e c t s changes i n the plant species and the growth stage a v a i l a b l e ( F i g . 6 ) .  Peccaries consume the best q u a l i t y foods that are  a v a i l a b l e , but always make use of the omnipresent p r i c k l y pear i n south Texas.  In west Texas, s o t o l and l e c h u g u i l l a as well as p r i c k l y pear take  the r o l e of south Texas p r i c k l y pear i n the peccaries' d i e t (Jennings and H a r r i s , 1953).  Although s p e c i f i c information on the n u t r i e n t q u a l i t y of  the food items found i n the peccary d i e t i s not a v a i l a b l e , d e t a i l s of the n u t r i e n t q u a l i t y of some of these items at various stages of growth have been published ( M i l l e r ,  195S; Sampson, 1952).  Determination of the forage  101 .  c l a s s composition of the stomach contents at various times of the year and under d i f f e r e n t c l i m a t i c conditions can then be used to i n f e r the q u a l i t y of food consumed. P r i c k l y pear i s by f a r the most common of the forages used by peccaries i n south Texas (Fig. 6 ) , and s o t o l , l e c h u g u i l l a and p r i c k l y pear are  the dominant species i n west Texas peccary stomachs (Jennings and  H a r r i s , 1953).  However, they are low i n protein and high i n carbohydrates  ( M i l l e r , 1958; Hoffman and Darrow, 1964). Although the stomach of the peccary i s three-parted and more complex than the monogastric stomach of the p i g , i t has not yet been shown that fermentation and production of v o l a t i l e f a t t y acids occur i n the peccary stomach (Moir, 1968; L. Sowls, pers. comm.).  Thus, although car-  bohydrates are always abundant i n the d i e t , the low protein l e v e l i n the winter d i e t could be a severe l i m i t a t i o n on the u t i l i z a t i o n of the carbohydrates (Maynard and L o o s l i , 1962).  With good r a i n f a l l and  consequent  abundance of high protein forage the animals can be expected to make more e f f e c t i v e use of the carbohydrates a v a i l a b l e i n p r i c k l y pear (Maynard and L o o s l i , 1962). Body condition of peccaries followed a seasonal pattern very s i m i l a r to that found i n south Texas w h i t e t a i l deer by White (1966). During part of the same period he also found that the seasonal pattern was strongly influenced by r a i n f a l l over the preceding vegetation growth period.  In both species i t was found that high r a i n f a l l , good range conditions,  and good animal condition are c o r r e l a t e d , as are low r a i n f a l l , poor range conditions, and poor animal c o n d i t i o n .  Although there  i s a l a g between  each of the events, i t i s not possible to put an absolute value on the r e a c t i o n period.  S u f f i c e i t to say that the response of vegetation to  r a i n f a l l occurs within a few days, depending on temperature, and the response i n animal condition occurs within a few weeks. N u t r i t i o n has important influences on growth and reproduction (Maynard and L o o s l i , 1962).  Animals that are undernourished have a slower  growth rate than adequately nourished animals, but may s t i l l a t t a i n a normal maximum weight (Maynard and L o o s l i , 1962).  In peccaries, a slower growth  r a t e would a f f e c t the age at maturity and therefore influence the p r o d u c t i v i t y of the i n d i v i d u a l and the population. An estimate of differences between the populations, i n growth patterns and attainment of adult s i z e and of condition differences between populations and under d i f f e r e n t c l i m a t i c conditions showed that the captive animals i n good n u t r i t i o n a l regime out  102.  performed the w i l d animals.  There i s an a s s o c i a t i o n between the a v a i l a b i l i t y of forages high i n protein and the achievement  and maintenance of good body c o n d i t i o n .  Fat  deposits r e f l e c t the n u t r i t i o n a l adequacy and abundance of forages (NAS-NRG, 1962), and, within wide l i m i t s , i n d i c a t e the p h y s i o l o g i c a l condition and reproductive s t a t e of the animal (Riney, 1955; Taber, et a l ; 1959).  Condition  of the ungulates has been commonly assessed by determining the amount of p e r i r e n a l f a t (Riney, 1955; Ransom, 1965) and although i t i s not s t r i c t l y o b j e c t i v e i t appears to be the most p r a c t i c a l method a v a i l a b l e .  Correlation  of p h y s i c a l condition with p e r i r e n a l f a t deposits i s based on extensive f i e l d and autopsy data i n a number of ungulates (Cheatum, 1949; H a r r i s , 1945; Riney, 1955).  I assumed that a s i m i l a r r e l a t i o n s h i p also applied to  peccaries. Body condition, as measured by kidney f a t , showed a p a r a l l e l r e l a t i o n s h i p with range conditions i n south Texas animals ( c f . F i g s . 5, 6 and 7 ) .  During the above-average r a i n s i n l a t e 1965 and early 1966,  pec-  c a r i e s had higher kidney f a t l e v e l s , and even put on dorsal f a t . During the drought of 1966 and 1967, kidney f a t l e v e l s were lower, and there was no dorsal f a t present on the animals (Table 2, F i g . 7 ) . In west Texas, both male and female peccaries were i n s l i g h t l y better condition i n 1966 than i n 1965 because of the b e t t e r range conditions r e s u l t i n g from the good d i s t r i b u t i o n of r a i n through the year (Table 2). S i m i l a r l y , change i n body weight, also p a r a l l e l l e d the general r a i n f a l l l e v e l and range conditions (Table 5).  Carcass weights were heavier  during the period of good range conditions i n south Texas, and l i g h t e r during the drought.  In west Texas, the weights of the males were s l i g h t l y heavier  during wetter year, 1966, but females, however, were s l i g h t l y l i g h t e r (Table 5).  This was p o s s i b l y because of the higher r a t e of pregnancy, and con-  sequent energy drain of l a c t a t i o n , which r e s u l t e d from b e t t e r range cond i t i o n s i n 1966. Since kidney f a t l e v e l s i n west Texas peccaries were lower and carcass weights s l i g h t l y l i g h t e r (despite s i m i l a r body length and height) than south Texas peccaries under poor range conditions, i t appeared that they were i n s l i g h t l y poorer c o n d i t i o n .  likely  Further evidence of t h e i r poorer  condition was the slower growth rates i n the west Texas animals.  Even  the south Texas peccaries were not l i v i n g i n optimal conditions,  f o r they  had generally lower kidney f a t l e v e l s , and reached"mature weights l a t e r than peccaries r a i s e d i n c a p t i v i t y ( F i g . S).  Growth rates of peccaries i n  c a p t i v i t y and south Texas showed differences consistent with the differences in condition.  103. Captive animals reached adult weights at 18 months, south Texas animals between 2 and 3 years.  I n s u f f i c i e n t young animals were c o l l e c t e d from  west Texas to compare growth curves, but they appear to be s i m i l a r to south Texas peccaries. The four peccary papulations studied i n Texas g e n e r a l l y showed a decrease i n density that p a r a l l e l e d the east-west decrease i n p r e c i p i t a t i o n ( c f , Table 7 and F i g . 1).  Peccary populations show a clumped d i s t r i b u t i o n  both of i n d i v i d u a l s and of herds, and no sampling method has yet proven successful f o r accurately censusing peccaries (Jennings and H a r r i s , Day, 1962,  '64, *65, '66, '67a; E l l i s o r and Harwell, 1969).  1953;  Only a t o t a l  count of a l l animals i n a l l herds can give an accurate determination of density, and s i n c e t h i s was not p r a c t i c a l , d e t a i l e d a n a l y s i s of density changes i s precluded.  However, i t was p o s s i b l e to obtain approximations  of population s i z e adequate to permit the comparisons necessary f o r t h i s study. A t o t a l count was p o s s i b l e only on the Welder Refuge where the peccary population and the area of the Refuge were small enough and the number of i n t e r e s t e d persons t r a v e r s i n g  the area l a r g e enough that a  reasonable count was obtainable. The density was estimated at 10 peccaries/sq. mile and was considerably l e s s than the estimate of 64 peccaries/sq. mile by E l l i s o r and Harwell (1969) i n an area of good habitat 30 miles northwest of the Refuge.  I t should be noted that the Refuge was  at the edge of the present geographical ranch of the species, and l e s s than a quarter of the Refuge represents s u i t a b l e h a b i t a t . On the King Ranch, the contagious d i s t r i b u t i o n of the peccary herds i s complicated by brush c l e a r i n g programs.  Complete removal of brush  from surrounding areas has caused peccaries to concentrate i n areas that s t i l l have some cover (V.W.  Lehmann, pers. comm.).  These d i f f i c u l t i e s must  be considered when attempting to determine the population density of the area.  Both problems could be overcome, but only at considerable expenditure  of both time and money.  H e l i c o p t e r surveys i n four pastures on the King  Ranch by K i e l (1963), i n 1962 and 1963, showed that peccary d e n s i t i e s varied considerably between pastures (Table 28).  The accuracy of the estimates of  density that K i e l obtained was l e s s than + 25°/o.  104. Table 28.  Peccary density estimates on s e l e c t e d pastures on the Santa Gertrudis D i v i s i o n of the King Ranch determined from a h e l i c o p t e r survey by K i e l (1963). D e n s i t y  Pasture Mesquite Ebanito Upper L i t t l e North Canelo a b c d  -  1962  b  11 .4 5.1 6.3 5.5  (peccaries/sq mile) 1963° 38.8 8.0 8.7  ..  d  Mean 17.6 6.2 6.3 6.7  accurate to l e s s than±25°/o determined from 9 transects covering 3,240 acres determined from 5 transects covering 3,904 acres mean density i n peccaries/sq mile  My s t r i p count estimates o f peccary density i n the area of Mesquite Pasture showed a density that averaged 21.8 peccaries/sq. mile.  Despite the f a c t  that the mean estimates o f density i n the a e r i a l and t e r r e s t r i a l  censuses  were quite s i m i l a r on Mesquite Pasture, the accuracy and s e n s i t i v i t y of the technique i s not adequate to permit comparison from year to year.  Twenty  miles NNE of the King Ranch i n h a b i t a t s i m i l a r to that on the King Ranch, E l l i s o r & Harwell (1969) counted a l l peccaries i n herds on t h e i r study area and determined the density to be 32 peccaries/sq. mile.  Estimates of d e n s i t i e s  of peccaries i n west Texas i n d i c a t e sparse populations i n both the Black Gap Area, 6.4 peccaries/sq. mile (L.S. Brownlee, Pers. Comm.) and the Wat-sbm' Ranch,v, 3.1 peccaries/sq. mile. The evidence provided by the home range data i s consistent with the density data.  Populations l i v i n g i n h a b i t a t s c h a r a c t e r i z e d by sparse  vegetation and l i m i t e d surface water may need to t r a v e l considerably more, and maintain a l a r g e r home range to maintain themselves than populations on l e s s harsh areas. The south Texas r e s u l t s o f home ranges of l e s s than 3/4 sq mile are s i m i l a r to those of Jennings and H a r r i s (1953), and E l l i s o r and Harwell (1969). E l l i s o r and Harwell (1969) followed b e l l e d herds and found the home range to be about 311 acres i n t h e i r densely populated area 30 miles NW of .the Welder Refuge, and 548 acres i n t h e i r l e s s densely populated area 20 miles NNW of the King Ranch.  E l l i s o r and Harwell (1969) observed eight males making i n t e r -  herd movements of distances up to 3 miles. In west Texas the home range i s considerably l a r g e r , upto 3 or 4 sq miles, concomitant with the lower density of vegetation and animals.  105. My r e s u l t s i n d i c a t e l a r g e r home ranges than Jennings and H a r r i s (1953) who i n d i c a t e a l i n e a r range of 2 to 3 miles up and down draws.  However,  work cn Arizona peccaries, l i v i n g i n habitat s i m i l a r to the west Texas animals, (Neal, 1959b, Day 1968) has shown the range there" <to be about 1 1/2 sq. miles, considerably l e s s than f o r the west Texas animals. There are no important d i f f e r e n c e s i n the age-specific/sex r a t i o s of the south and west Texas populations (Table 5 ) , nor between these and populations i n Arizona studied by Sowls (1966) and Knipe (1958).  The  predominance of females i n the f o e t a l sex r a t i o s that I found i n the Texas populations has also been found i n Arizona peccaries and would thus appear to be. a feature of the species. The mechanism of the abrupt change i n sex r a t i o s to favour males during the neonatal period i s unknown, but the predominance of males i n the young age classes and the progressive change to predominance of females in the o l d e r age classes has been reported f o r many species.  I d i d not  determine what the causes of these d i f f e r e n t i a l m o r t a l i t y rates between sexes were. Analysis of population s t r u c t u r e of peccaries i n south and west Texas populations showed that the population s t r u c t u r e i n south Texas was skewed considerably toward older animals compared with the west Texas population.  F i f t e e n percent of the south Texas population was between  7-and 15-years o l d , whereas l e s s than 7% of the west Texas population was 7—years or older.  The oldest animal obtained i n west Texas, was e s t i -  mated at 9—years o l d .  The d i f f e r e n c e s appear to be associated with a  s l i g h t l y higher m o r t a l i t y r a t e throughout l i f e i n west Texas populations (Tables 7 and 8 ) . Although the slopes of the regressions f o r the two popu l a t i o n s are not s i g n i f i c a n t l y d i f f e r e n t , data f o r the Black Gap Area are limited.  Although the Black Gap Area was hunted and the Watson Ranch was not,  the age s t r u c t u r e of these two west Texas areas i s very s i m i l a r .  Thus i t  would appear that i t i s the harsher west Texas environment that has r e s u l t e d in the s l i g h t l y higher m o r t a l i t y r a t e of animals there than i s present i n south Texas. There are several p o s s i b l e biases i n these data.  In my personal  collections I i n i t i a l l y  t r i e d to c o l l e c t females only, but found i t im-  p r a c t i c a l to continue.  However, there i s s t i l l some bias present  the study.  through  In the hunter k i l l e d animals, bias would probably be toward a  bigger animal as discussed by Sowls (1961 a).  Since there i s l i t t l e d i f f e r e n c e  i n s i z e between sexes there should be l i t t l e bias towards e i t h e r sex.  106. Another explanation f o r the higher proportion of females i n the older age groups could be the f a c t that many o l d males take up a s o l i t a r y existence, and are not c o l l e c t e d as frequently.  However, s o l i t a r y animals are common  to both the west and south Texas populations, hence, the same bias would be evident i n the two areas.  There was no consistent d i f f e r e n c e i n sex  r a t i o s of animals conceived or born under d i f f e r e n t p r e c i p i t a t i o n conditions (Table 9 ) . Changes i n the s i z e and density of a population are obviously induced by changes i n reproduction and s u r v i v a l .  The production of young  i s the r e s u l t of the i n t e r a c t i o n of many i n t e r r e l a t e d environmental and p h y s i o l o g i c a l events, and i t may be r e a d i l y a f f e c t e d by changes i n any of the events upon which i t depends.  Proper understanding  of reproduction i n  a species n e c e s s a r i l y e n t a i l s examination of the process i n both sexes. In c o n t i n u a l l y breeding species, as the peccary i s , the male i s presumed to be capable of f e r t i l i z i n g the female throughout the year.  In  peccaries there i s a b r i e f period i n the hot dry part of summer when l i t t l e successful mating occurs (Jennings and H a r r i s , 1953; Sowls, 1966,', t h i s study). This suggested that e i t h e r reduced l i b i d o , or short term s t e r i l i t y , i n the male might be involved.  Analysis of weights and h i s t o l o g i c a l structures of  the testes did not reveal any obvious change that could be associated with t h i s period.  Weights and the t e s t i s index of a l l adult males c o l l e c t e d  did show some reduction i n s i z e i n the winter ( F i g . 15). H i s t o l o g i c a l examination of testes of average and below average s i z e i n d i c a t e d that the changes i n the tubule diameter or the percentage tubules i n t e r s t i t i u m and the number of sperm per tubule cross-section changed r e l a t i v e l y  little  throughout the year ( F i g . 17). However, there was no obvious change i n the testes during the hot part of the summer that could be equated with a decrease i n r e p r o d u c t i v i t y a b i l i t y or l i b i d o .  Fraser (1969) has pointed out that l i b i d o i s not j u s t a  function of androgen production i n the t e s t e s , but i s p r i n c i p a l l y under cerebral c o n t r o l . Van Tienhoven (1968), however, points out that admini s t r a t i o n of androgen to castrates restores the former sex d r i v e .  Because  hormone production i s a f f e c t e d by decreased protein intake (van Tienhoven, 1968), i t i s p o s s i b l e that there i s a decrease i n l i b i d o i n peccaries-.as a r e s u l t of the decrease i n proteinaceous previously.  forage i n l a t e summer suggested  I t i s equally p a s s i b l e that hot weather i t s e l f could i n l a t e  summer cause a decrease i n l i b i d o i n the male.  107. Comparison of the h i s t o l o g i c a l s t r u c t u r e s of a small sample of testes between the wet and drought periods showed that there was a s i g n i f i c a n t d i f f e r e n c e only i n the amount of sperm present. . The number of sperm, although lower i n the dry period were s t i l l judged to be more than s u f f i c i e n t f o r successful f e r t i l i z a t i o n . Maturation of males i s l a t e r i n west Texas peccaries than i n both south Texas and pen-reared peccaries.  Captive males are capable of  f e r t i l i z i n g females at 10 1/2 to 11 1/2 months (Sowls, 1966;  t h i s study)  and south Texas peccaries possess l a r g e numbers of sperm i n the testes by 11 months.  However, west Texas males did not have many sperm i n the testes  u n t i l about 15 months.  T e s t i s s i z e i n west Texas males show the same  retarded growth (Tables 13 and 15).  Because of the lower condition l e v e l s  of the west Texas peccaries, these d i f f e r e n c e s are to be expected. evidence suggests that t e s t i c u l a r growth and maturation  Limited  age depend upon  the time of year, as w e l l as upon the c l i m a t i c , hence vegetation, conditions during which the young animal approaches maturation.  A 3-month o l d male  (P-52) c o l l e c t e d i n November, 1965,  whereas twin males  had a TI of 0.16,  (P-104, and P-105) 3 1/2 months^.old, c o l l e c t e d i n J u l y , 1966, i n d i c e s of Q.,34  had  testis  and 0^4. . Both of these were during the above average  r a i n f a l l period, but food conditions i n the f a l l are not as favourable as in the s p r i n g .  Further evidence of the e f f e c t of condition i s provided  by three pen—reared Welder 3.7—month o l d peccaries.  The twins (Pc159 and  Pc160) who were the same age, but one t h i r d the carcass weight of the s i n g l e (Pc 158), both had TI of 0.32,  whereas the s i n g l e had a TI of  0.55.  The twins were r a i s e d by a sow that l a c t a t e d poorly, and the s i n g l e was  still  nursing when k i l l e d . Sperm production i s also a f f e c t e d by c o n d i t i o n , as shown by males about 9 1/2 months o l d .  P-70,  c o l l e c t e d i n March 1966 f o l l o w i n g a  favorable winter, had a kidney f a t index of 1/4;  P-128, c o l l e c t e d i n A p r i l ,  1967 a f t e r 8 months of drought had a kidney f a t index of 1/8. average of 9.2  two  P-70  had an  sperm per tubule c r o s s — s e c t i o n , whereas P—128 had an average  of 0.2 per tubule c r o s s - s e c t i o n .  Older animals show v a r i a b i l i t y ,  nevertheless  the i n t e r p r e t a t i o n i s consistent with r e s u l t s quoted by S a d l e i r (1969) and Fraser  (1969). S e n i l i t y i s another f a c t o r which might i n f l u e n c e reproductive  r a t e and p r o d u c t i v i t y , p a r t i c u l a r l y i n populations with a high proportion of o l d animals.  The oldest males c o l l e c t e d were 14, 13.8,  (estimated from dental annulations).  and 12 years o l d  A l l of these had t e s t i s i n d i c e s above  108. 2.0, and the 14 and 12 year olds had p l e n t i f u l supplies of sperm i n the tubules. The 12-year o l d (P-5) had an abnormally l a r g e l e f t and poorly developed r i g h t t e s t i s .  No sperm were observed i n the vasa e f f e r e n t i a of  the l e f t t e s t i s despite i t s having the highest average sperm count  155  per tubule c r o s s - s e c t i o n with up to 244 sperm i n one c r o s s - s e c t i o n .  The  14-year o l d (P-86) had 76 sperm per tubule c r o s s - s e c t i o n , only s l i g h t l y l e s s than the o v e r a l l average of 91.  A 9.2 year o l d west Texas male (\IVT-1), a  r e l a t i v e l y o l d male i n view of the younger population i n west Texas, had a low sperm count of only 40. The proportion of i n t e r s t i t i a l t i s s u e i n P-86 lower than average. be expected.  and WT-1  was  slightly  Hence a decrease i n androgen and perhaps l i b i d o might  Parkes (1966) found a great deal of i n t e r s t i t i a l t i s s u e i n  the t e s t i s of an o l d 100-pound captive c o l l a r e d peccary.  Judging from the  weight, the animal was extremely f a t , and the r e s u l t i n g increased i n t e r s t i t i a l t i s s u e lends support to my hypothesis that c o n d i t i o n i n f l u e n c e s t e s t i s histology.  The r o l e that o l d e r males take i n breeding i s not known, but  the f a c t that many older boars seem to take up s o l i t a r y existence suggests that they do not play an important part in. reproduction even though there i s no evidence of s i g n i f i c a n t d e c l i n e i n the number of spermatozoa demonstrated i n the tubules. Although appreciation of the male r o l e i s necessary,  reproduction  i n the female i s more s t r i k i n g l y responsive to changes i n h a b i t a t .  I t has  already been shown that body c o n d i t i o n i s responsive to changes i n c l i m a t i c and range c o n d i t i o n s .  In t h i s study I have examined the response of r e -  productive pattern i n the female to d i f f e r e n t c l i m a t i c conditions on  one  habitat and to a l e s s e r extent.between a mesic and an a r i d h a b i t a t .  I have  attempted to analyse reproduction i n the f i e l d through examination productive t r a c t s , p a r t i c u l a r l y the ovary, of w i l d peccaries.  of r e -  The ovary  can  provide-.much a d d i t i o n a l information on reproductive patterns and rates (Cheatum, 1949; Golley, 1957; Thomas, 1970)  and i n e f f e c t serves to increase  the amount of data derived from the r e l a t i v e l y small sample of reproductive t r a c t s a v a i l a b l e . The a n a l y s i s of reproduction i n w i l d peccaries i s compared with reproduction i n the pen-reared peccaries with known reproductive h i s t o r y . The gross morphology of the reproductive t r a c t described e a r l i e r i s s u b s t a n t i a l l y the same as Wislocki's (1931) d e s c r i p t i o n . The remarkable feature i s the short F a l l o p i a n tubes which are approximately i n both v i r g i n and pregnant animals.  the same length  109. Sowls (1966) d e s c r i p t i o n of the mammae i n Arizona peccaries a p p l i e s also to the Texas subspecies.  W i s l o c k i ' s (1931) and Jennings  and H a r r i s ' s (1953) d e s c r i p t i o n s of the mammae are correct f o r f u n c t i o n a l mammae but they apparently d i d not observe the v e s t i g i a l two p e c t o r a l p a i r of mammae. My i n t e r p r e t a t i o n of the ovarian s t r u c t u r e s d i f f e r s from W i s l o c k i ' s (1931) d e s c r i p t i o n of the ovary i n a pregnant sow only on i n t e r p r e t a t i o n of h i s "degenerate corpus luteum".  I t i s necessary to.examine  early  development o f the ovary i n order to understand the presence o f t h i s 'degenerate corpus', which i s a c t u a l l y an unusual r e t e n t i o n of a secretory medullary body. According to Burns (1961:102), i n normal mammalian sex d i f f e r e n t i a t i o n , the i n d i f f e r e n t gonad i s formed from the g e n i t a l ridge and has a medullary portion and a germinal e p i t h e l i a l l a y e r .  During the primary  p r o l i f e r a t i o n , the germinal epithelium produces primary (or medullary) sex cords which 'bud' i n t o the medullary area.  At t h i s stage, the medullary  region represents the male component, and the germinal epithelium represent the p o t e n t i a l cortex o r female p o r t i o n .  At t h i s early stage, the male sex.  cords connect to the rete cords (the mesonephric  connecting tubules) which  juxtapose the glomerular capsule of the embryonic kidney.  I f the sex of  the foetus i s male, the primary sex cords develop, and the germinal epithelium i s reduced to a t h i n membrane.  The t u n i c a albuginea develops,  subadjacent to the v e s t i g i a l germinal epithelium and the rete cords became the r e t e t e s t i s connecting  the seminiferous tubules (primary sex cords) to  the vasa e f f e r e n t i a . I f the sex i s female, a second p r o l i f e r a t i o n by the germinal epithelium produces the secondary (or c o r t i c a l ) sex cords which surround the medullary p o r t i o n .  The male sex cords are reduced, and they and the  rudimentary t u n i c a albuginea g r a d u a l l y disappear.  The c o r t i c a l cords go on  to form the cortex, and subsequent p r o l i f e r a t i o n from the p e r i p h e r a l germinal epithelium produces the p r i m o r d i a l f o l l i c l e s .  The medullary region  becomes i n d i s t i n c t through regression and dispersion of the cord c e l l s , and invasion by the c o r t i c a l c e l l s . However, Gropp and Ohno (1966) have proposed a d i f f e r e n t concept of gonadal d i f f e r e n t i a t i o n i n c a t t l e and conclude that f o l l i c u l a r c e l l s of the ovary and i n t e r s t i t i a l c e l l s o f the testes are homologous (van Tienhoven,  1968).  110.  They consider that the function of the germinal epithelium i s minimal, and that secondary sex cords are not observed.  In the male, the semi-  niferous tubules enlarge from ' f o c i ' i n the deeper areas of the blastema, and engulf germ c e l l s which have migrated i n t o the area.  In the female  the outer c e l l l a y e r s of the blastema arrange themselves i n t o f o l l i c u l a r cords and develop outwards to make contact with, and engulf, the peripheral l a y e r of immigrating oogonia to become avigerous cords. Development of the peccary ovary i s unusual i n the retention of the tunic-surrounded medulla throughout l i f e .  Leach and Conaway (1963)  working on the s t r i p e d skunk found that the ovarian medulla p e r s i s t s with primary sex cords present u n t i l about 11 weeks post-partum when i t degenerates to a mass of i n t e r s t i t i a l t i s s u e .  P r i o r to that time, the cortex  shows very l i t t l e development and i t i s not u n t i l the medulla degenerates that the cortex develops.  Deansly (1966), working on the mole, describes  a s t r u c t u r e in,, the mole ovary which i s s i m i l a r to that found i n the peccary. This she terms the medullary part, and she has found that the s t r u c t u r e enlarges and regresses with the end and beginning of the mating period. H i s t o l o g i c a l analysis of the peccary ovaries revealed that females i n south Texas have started to form corpora l u t e a of oestrus around 8 months. These probably coincide with " s i l e n t " heats as laboratory animals did not mate u n t i l about 11 months. mated at 8 months.  Sowls (1966) however, r a i s e d one female that  No w i l d peccaries were found pregnant u n t i l a f t e r they  were 16 months o l d , and most appear to become pregnant i n the l a s t h a l f of t h e i r second year.  Although there was l i t t l e d i f f e r e n c e between west and  south Texas peccaries i n age at f i r s t pregnancy ( l a r g e l y due to small sample s i z e and time of c o l l e c t i o n of the west Texas specimens) there was some evidence of delay, of maturity during the drought period i n south Texas. The only two females that had reached 2 years o l d without becoming pregnant were c o l l e c t e d i n March, 1967 (drought period) a f t e r the peak mating period. They had not been pregnant and they d i d not show any ovarian i n d i c a t i o n of recent ovulations. Maximum ovulation and implantation rates were not reached u n t i l about 5 years (Table 23).  This coincides with the age at which maximum  s i z e of the animal i s reached ( F i g . 10).  I t appears that the animal can  then channel most of i t s energy i n t o reproduction rather than having to • d i v e r t some to growth (Maynard and L o o s l i , 1962) .  111. Sowl's (1966) information on penned peccaries i n d i c a t e s they are p o l y o e s t r a l and have an oestrous c y c l e l a s t i n g 22.6 to 24.6 days and duration of oestrous averaging 3.5 to 4.8 days.  Our l e s s i n t e n s i v e  examination of the oestrous c y c l e i n penned animals showed s i m i l a r r e s u l t s with wide v a r i a t i o n .  Behavioural data obtained on pen-reared peccaries  at U.B.C. are c o n s i s t e n t , though conception was g e n e r a l l y a l i t t l e l a t e r (Table 21). Age of maturation appears to be c o n t r o l l e d by the condition of the range and season.  The l i m i t e d data suggest that i f the female i s  over 12 to 15 months o l d during the major winter breeding season, she probably becomes pregnant.  However, i f she was born i n the f a l l ,  then  she w i l l probably not mature u n t i l the winter when she .is about 18 months old.  Poor range conditions apparently can retard the age o f maturation  by at l e a s t 6 months. Sowls (1961b, 1966) found the gestation period f o r peccaries to range' from 141 to 150 days with a mean (maximum) of 145.8 days. Sowls (1966:161) shows i s a r e s u l t of a m i s c a l c u l a t i o n .  The range  The data derived  from t h i s study agree rather c l o s e l y with Sowls data. Hafez (1964) found that some domestic animals tend to have s l i g h t l y longer g e s t a t i o n periods i f the gestation period i s p r i m a r i l y during the winter. /There i s a tendency to t h i s i n the captive animals r a i s e d at U.B.C. although the difference i s not s i g n i f i c a n t .  The mean of s i x gestation  periods where the young were born between January and A p r i l , i s 144.5 days (+ 0.5 S.E).  The mean of seven gestation periods r e s u l t i n g i n June to  October b i r t h s averaged 142.8 days ('+ 0.9 S.E).  There was also a tendency  f o r l i t t e r s of one to have a shorter g e s t a t i o n and l i t t e r s of three to have a longer g e s t a t i o n period, although the d i f f e r e n c e s are not s i g n i f i c a n t . This range i n length of gestation period t h e o r e t i c a l l y permits the b i r t h of two l i t t e r s per year to each sow. Breeding takes place throughout the year, but i s concentrated i n two peaks.  Backdating to conception date of foetuses, using the formula  of Hugget and Widdas (1951) and growth curves of U l l r e y , et a l . , (1965) and Thomas (1970), and observations of young i n the f i e l d , revealed a major breeding season between December and February and a minor peak i n A p r i l or May i n south Texas peccaries. The ultimate s e l e c t i v e pressure on timing of the breeding season i s probably through s u r v i v a l of young during the vegetative growing seasons of l a t e s p r i n g — e a r l y summer, and the f a l l .  112. The exact time of the peak of breeding appears to be influenced by several f a c t o r s .  R a i n f a l l seems to be the most important f a c t o r .  It  acts i n d i r e c t l y through range conditions r e s u l t i n g from previous seasonal r a i n f a l l and more d i r e c t l y through the presence of green plants containing high protein and perhaps estrogen l e v e l s .  S a d l e i r (1969') and Samuel (1967)  have reviewed, r e s p e c t i v e l y , the e f f e c t s of p r o t e i n - - r i c h d i e t s causing " f l u s h i n g " , and the e f f e c t of estrogen-like compounds on reproduction. The s i t u a t i o n i s probably s i m i l a r i n west Texas, but data are not adequate to show the pattern over the whole period.  On the Black Gap  area i n 1966 spring r a i n s supplemented by heavy r a i n s i n August, September and October, r e s u l t e d i n r e l a t i v e l y high production of young i n the l a t e fall.  On the Watson Ranch, the p a r t u r i t i o n peak i n 1966 was i n May and June,  f o l l o w i n g November and February r a i n s .  The s i t u a t i o n i n west Texas appears  s i m i l a r to that described by Sowls (1966, 1961a) i n Arizona. Thus peccaries have what might be termed an o b l i g a t o r y reproductive period i n the winter and s p r i n g , and are f a c u l t a t i v e breeders throughout the remainder of the year.  The winter breeding period appears to be keyed  to a p a r t u r i t i o n period c o i n c i d i n g , i n general, with the r e l a t i v e food abundances of the spring and summer vegetation growing period.  As Sowls  (1966) has suggested f o r Arizona peccaries, s u r v i v a l of the young would be the ultimate s e l e c t i v e f a c t o r c o n t r o l l i n g the winter breeding period. This same c o n t r o l has been proposed f o r the Sonoran w h i t e - t a i l e d deer (McCabe and Leopold, 1951).  In a d d i t i o n , p r e c i p i t a t i o n - c o n t r o l l e d range  conditions might be regarded as the proximate f a c t o r c o n t r o l l i n g exactly when, during the winter, the animals do breed, and whether they can take advantage of a second breeding season i n l a t e spring or. e a r l y summer. I t appears that the breeding season i n the peccary i s . b a s i c a l l y the c o n t i n u a l optimal season type of S a d l i e r (1969), but at the north edge of the range i n Texas i t has adapted to a f i x e d , but i r r e g u l a r , optimal season f o r production of young.  Since the optimal season i s u s u a l l y very  long i n south Texas, from March to November, peccaries take advantage of i t by producing one l i t t e r of young e a r l y i n the optimal period, and l i t t e r during the l a s t t h i r d of the optimal period.  another  This would combine  S a d l e i r ' s (1961:51) Type 4 and 5 breeding patterns concerning length of time from conception to weaning i n r e l a t i o n to the optimal season.  As  S a d l e i r suggests, there might be a higher r a t e of m o r t a l i t y of the l a s t l i t t e r s as a r e s u l t of the u n p r e d i c t a b i l i t y of the end of the optimal period. Reinforcement of l a t e breeders would be i r r e g u l a r i n t h i s case.  113. As a r e s u l t of more intense seasonal changes and a more r e s t r i c t e d favourable breeding season, the reproductive period i n west Texas i s shorter. However, i n years with good range c o n d i t i o n s , breeding probably extends over the major part of the year a l s o . A measure of the s t r e s s on a population can be determined by comparing p r o d u c t i v i t y of the studied population with some known standard. The present comparison of p r o d u c t i v i t y i n a south Texas population during a drought and a moist year, with more l i m i t e d data on p r o d u c t i v i t y i n a west Texas population during a semi-drought  and a moist year revealed im-  portant d i f f e r e n c e s from the p r o d u c t i v i t y of pen-reared animals. P r o d u c t i v i t y can be determined at s e v e r a l points i n the l i f e cycle: ovulation incidence, conception r a t e , implantation r a t e , f o e t a l counts, p a r t u r i t i o n r a t e s , and j u v e n i l e counts.  I have determined the o v u l a t i o n  incidence (from corpora l u t e a or CL-P s c a r s ) , gross p r o d u c t i v i t y (from f o e t a l counts), and net p r o d u c t i v i t y (from r a t i o s of j u v e n i l e s to a d u l t s ) . Ovulation incidence provides the p o t e n t i a l number of young the sow, or population, could produce under e x i s t i n g c o n d i t i o n s . Gross p r o d u c t i v i t y (commonly r e s t r i c t e d to the b i r t h rate) provides an estimate of embryonic m o r t a l i t y , and net p r o d u c t i v i t y (the recruitment to adult populations) provides an estimate of post—natal m o r t a l i t y . Peccaries are capable of reproducing twice a year.  Therefore, i t  i s necessary to separate o v u l a t i o n and implantation,incidence, that i s , the number of ova shed and the number of embryos implanted per pregnancy, from the o v u l a t i o n and implantation r a t e s , that i s , the number of ova shed and the number of embryos implanted per year. The o v u l a t i o n r a t e i s d i f f i c u l t to determine i n w i l d peccaries because i t necessitates determining the number of scars of pregnancy formed i n the ovary e i t h e r during a year, or during the l i f e t i m e of the animal. I did not think that my counts of scars of pregnancy were accurate enough to determine the r a t e of implantation during the animal's l i f e t i m e f o r some of the o v a r i e s , p a r t i c u l a r l y those with l a r g e corpora l u t e a .  However, i n  pregnant animals i n which the l a s t previous CL-P was s t i l l regressing, I could say with reasonable c e r t a i n t y i t h a t the animal had conceived twice i n that year.  The period a c t u a l l y covered i s somewhat l e s s than 10 months,  since the corpora regress quite r a p i d l y and by 5 months reach a s i z e at which they are d i f f i c u l t to d i s t i n g u i s h from e a r l i e r scars of pregnancy (Fig. 20).  Thus, with the f i v e months gestation p r i o r to i n i t i a t i o n  of  degeneration, a period of about 10 months i s obtained over which frequency of pregnancy can be  determined.  114. Since peccaries i n west Texas were i n poorer condition than south Texas peccaries, and those under drought conditions were i n poorer condition than those under good range conditions, i t i s p e c u l i a r that there i s no d i f f e r e n c e i n ovulation r a t e s .  However, Hart and M i l l e r (1937)  found ovulation rates were not a f f e c t e d during short term n u t r i t i o n a l deficiencies.  Because the drought during the study i n south Texas l a s t e d  f o r only 13 months, i t i s l i k e l y the ovulation incidence had not been s e r i o u s l y a f f e c t e d i n that time.  I t i s more d i f f i c u l t to explain the lack  of s i g n i f i c a n t d i f f e r e n c e i n ovulation incidence between the west and south Texas populations. However, i t i s reasonable to expect that the decrease I have shown i n the implantation incidence during times of food s t r e s s i s r e a l . This has been shown f o r a number of mammals ( S a d l e i r , 1969). How in productivity.  often a sow becomes pregnant has important i m p l i c a t i o n s Domestic pigs have been shown to have an  anovulatory  post-partum oestrus and are generally anoestrous during l a c t a t i o n ( A s d e l l , 1964), but come i n t o oestrus s h o r t l y a f t e r young are removed (Nalbandov, 1964).  Several other species have oestrous cycles while l a c t a t i n g  (Perry and Rowlands 1962:299).  Sowls (1966) found that peccaries have a  post-partum oestrus 8'or more days a f t e r p a r t u r i t i o n that on one was f e r t i l e .  occasion  He also found that sows become pregnant while l a c t a t i n g .  I  have confirmed tKiis and found that captive peccaries frequently have a f e r t i l e oestrus 5 to 12 days a f t e r p a r t u r i t i o n .  With the f e r t i l e  oestrus  coming 5 to 12 days a f t e r p a r t u r i t i o n , i t i s possible f o r peccaries to have a l i t t e r every 5 months. (Table 19).  Sow  UBC 4 came close to r e a l i z i n g t h i s p o t e n t i a l  She produced seven l i t t e r s over a 3 1/4 year period, an average  of 5.7 months per l i t t e r .  A l l of her l i t t e r s were allowed to remain with her  f o r 2 to 3 months f o l l o w i n g p a r t u r i t i o n . With t h i s high p o t e n t i a l reproductive r a t e , comparison of performance of f i e l d populations was of i n t e r e s t . Animal c o n d i t i o n , as a r e s u l t of previous range conditions, a strong i n f l u e n c e on reproductive a c t i v i t y and gross p r o d u c t i v i t y . number of sows o v u l a t i n g and conceiving, and the ovulation and  has  The  implantation  rates a l l r e f l e c t the condition of the animal and the range upon which i t feeds.  In 1965 and 1966,  i n south Texas, p r o d u c t i v i t y was high (301  foetuses/  115. 100 adult sows i n 1966) as a r e s u l t of a high prevalence of pregnancy (71%) and rebreeding s h o r t l y a f t e r the f i r s t p a r t u r i t i o n (41%) .  In the  drought period there were only 118 foetuses/100 adult sows because of a low pregnancy r a t e (26%) and very few consecutive pregnancies ( 9 % ) . Data on p r o d u c t i v i t y o f west Texas animals are meagre; however, the range c o n d i t i o n - p r o d u c t i v i t y r e l a t i o n s h i p appears to be maintained. In 1965, a dry year, p r o d u c t i v i t y was low with l i t t l e l a t e season production of young, whereas i n 1966, a r e l a t i v e l y moist year, there was considerable production o f young i n the l a t e s p r i n g , the l a t e season production o f young was high. Thus, i t would appear that peccaries are able to take advantage of t h e i r high reproductive p o t e n t i a l during favourable f i e l d c o n d i t i o n s . During dry f i e l d conditions, however, not only do conceptions decrease, but also the oestrus c y c l e may be suspended. Net p r o d u c t i v i t y also changed with range condition and condition of the sow. During periods of good range c o n d i t i o n s , twins were common and t r i p l e t s o c c a s i o n a l , and s u r v i v a l during the neonatal period was r e l a t i v e l y good.  I t appears that at no time i s neonatal s u r v i v a l very high.  Even pen-born l i t t e r s l o s t 25% o f the young w i t h i n two days of b i r t h . Sowls (pers. comm.) however, found that s u r v i v a l of pen-born l i t t e r s was very high.  When range conditions were poor, the proportions o f s i n g l e s  increased, and although twins remained common i n utero, u s u a l l y no more than one o f the twins survived the neonatal period. The cause of death o f neonatants i s l a r g e l y unknown, but i n pen-reared  peccaries, young that died weighed much l e s s than those that  survived.  Studies o f the  e f f e c t s of plane o f n u t r i t i o n of the female  during the l a s t h a l f of pregnancy and l a c t a t i o n have shown reduced weight and s u r v i v a l of young on low-plane d i e t s (Thomson and Thomson, 1949, 1953; Pomeroy, 1960; Verme, 1962, 1965; Murphy and Coates, 1966; Sowls, 1966). I t i s l i k e l y that the response i s s i m i l a r i n w i l d peccaries since there i s such a high m o r t a l i t y of neonatants and neonatant m o r t a l i t y i s probably the major s i t e o f population " c o n t r o l " o f peccaries on a r i d land ranges. L i t t e r s i z e frequency i n w i l d Arizona peccaries (Sowls, 1966) d i f f e r s considerably from that i n south Texas (P<.1) (Table 22). higher proportion o f the sows there produce t r i p l e t s . true i n comparison o f pen-born l i t t e r s (P = .5).  A  This did not hold  Wild Arizona peccaries  produced t r i p l e t s 33% o f the time, although i n 48% of the cases, one of the t r i p l e t s was dead i n utero.  This i s curious i n view of the lower  n u t r i t i o n a l status of w i l d animals, and i s probably best explained by the  116.  sample s i z e .  Factors a f f e c t i n g adult and j u v e n i l e m o r t a l i t y are probably of l i t t l e consequence except during times of n u t r i t i o n a l s t r e s s . Predation,_ p a r a s i t e s , and diseases appear to be of minor importance (Appendix G). However, inclement weather, i n combination with low q u a l i t y , bulky food seems to take a high t o l l of a l l age classes (Appendix G) . In two herds, 29°/o of the animals died or disappeared during the cold period accompanying the drought of 1966-67.  At the same time the Welder Refuge deer herd  decreased by about 32% (Low, 1967, unpublished r e p o r t ) . Hunting can be an important f a c t o r i n vulnerable, i s o l a t e d herds, but i s l a r g e l y unassessed i n terms of e f f e c t s on whole populations.  Sowls  (1961a) suggested that the proportion of 11-to 21 1/2-month o l d peccaries k i l l e d i n the annual hunt i n Arizona ranged from 9 to 20% and was dependent on the p r e c i p i t a t i o n l e v e l f o r the period before they were bOrn.  The  r e s u l t s of t h i s study agree with h i s f i n d i n g s . A model of f a c t o r s a f f e c t i n g peccary populations i s shown i n F i g . 24.  Elimate, p r i m a r i l y p r e c i p i t a t i o n but also temperature, i s probably  the ultimate c o n t r o l of population density, acting mainly through food supply.  The mechanism of density " c o n t r o l " appears to be through food-  r e l a t e d changes i n p r o d u c t i v i t y , neonatal m o r t a l i t y , and winter m o r t a l i t y of j u v e n i l e s and a d u l t s .  P r o d u c t i v i t y i s c o n t r o l l e d p r i m a r i l y through im-  p l a n t a t i o n success, and prevalence and frequency of pregnancy.  Since  peccaries are capable of very high reproductive rates (two l i t t e r s annually of two to three foetuses per l i t t e r ) under i d e a l conditions,., the population can q u i c k l y take advantage of periods of good range conditions.  However,  severe food q u a l i t y r e s t r i c t i o n s may cause pregnancy rates to drop below the population maintainance l e v e l . There have been few studies of reproductive e f f i c i e n c y and population maintainance i n the l a r g e r herbivores l i v i n g under desert or semi-desert conditions.  Research on the red kangaroo (Newsome, 1966b,  et. a l . , 1967) euro (Ealey and Main, 1967) and on the w h i t e - t a i l e d deer i n Texas (White, 1966).have revealed that drought conditions i n a r i d and semi-arid environments act upon populations of l a r g e r herbivores f i r s t by r e s t r i c t i n g reproduction, and l a t e r by d i r e c t m o r t a l i t y of a l l age classes as a consequence of food shortage caused by water shortage.  I have shown  that the peccary i n Texas s i m i l a r l y responds to changes i n a r i d i t y by changes i n i t s reproductive success.  There i s also some evidence that  suggests that when r a i n f a l l i s below 70% of the mean, the death r a t e of adults r i s e s .  BEHAVIOR  R M G E MANAGEMENT 'Brush c l e a r i n g W a t e r management  — CLIMATE Temperature Rainfall Humidity  REPRODUCTION Ovulation rate Implantation rate Oestrus freuqitency Gestation frequency  ~~~\  VEGETATION Cover Food  POPULATION DENSITY  \  MORTALI TY Neonatal loss Recruitment f a i l u r e Adult death  GEOLOGY Topography Soils  MORTALITY FACTORS Predators P a r a s i t e s and d i s e a s e Hunting Poor n u t r i t i o n - Cold weather Catastrophies Hurricane, flood  Figure<^2itZ3 F a c t o r s a f f e c t i n g p e c c a r y  density.  • major c o n t r o l •> m i n o r o r p o t e n t i a l  influence  118.  In a r i d lands the balance between years of drought and years of s u f f i c i e n t r a i n f a l l f l u c t u a t e s so i r r e g u l a r l y and frequently that t h i s alone governs the density that these animals reach ( F i g . 25). There i s no evidence that mechanisms covering population s i z e i n the peccary populations are density dependent.  Seldom, i f ever, does density reach  a point where t r a d i t i o n a l i n t r i n s i c density dependent forces operate. In Texas the evidence a v a i l a b l e points to t h i s conclusion as a p p l i c a b l e during the period of t h i s study.  SUFFICIENT  PRECIPITATION  DROUGHT  SUFFICIENT  PRECIPITATION  Environmental resistance to population density  J J  J J J J vl J  if*  JJ J .  J J i q  I  i  \  J  j J J  DROUGHT  •  JIJJ  / 7* <?  High reproductive rate and s u r v i v a l Low r e p r o d u c tive rate & survival  • cu•or : ej.  High reproductive rate and s u r v i v a l Low r e p r o ductive rate & survival  •©••  •u.o: •a-  •r-r  High q u a l i t y  Model of process of population  food  change i n S o u t h Texas p e c c a r y  populations.  120.  6.  APPENDICES.  121 . Appendix A. S c i e n t i f i c names c f p i t s and animals c i t e d i n the t e x t . Nomenclature follows Jones, a l . ( l 9 6 l ) and Gould (1962) f o r the plants, Peterson (1963) f o r e b i r d s , and H a l l and Kelson (1963) f o r the mammals. Agarito Anacua Ayenia, dwarf Blackbrush Bristlegrass, plains sandhill southwestern Buffalograss Catclaw Chinograss Chittimwood Colubrina, Texas Creosote bush Croton  Berberis t r i f o l i o l a t a E h r e t i a anacua Ayenia p u s i l l a Acacia r i g i d u l a Setaria leucopila S. f i r m u l a S. s c h e e l e i Buchloe dactyloides  Croton, one—seed  Acacia g r e g g i i Bouteloua b r e v i s e t a Bumelia lanuginosa Colubrina texensis Larrea d i v a r i c a t a Croton texensis, C. capitatus, C. neomexicanus Croton monanthogynus  Goldeneye Granjueno Guajillo  V i g u i e r a stenoloba Celtis pallida Acacia b e r l a n d i e r i  Hackberry, n e t l e a f sugar Hairy tubetongue Huisache  Celtis reticulata C. l a e v i g a t a Siphonoglossa p i l o s e l l a Acacia farnesiana  Iceweed  Verbesina microptera  Junipers  Juniperus spp.  Lechuguilla Lotebush Lupine  Agave l e c h e g u i l l a Condalia o b t u s i f o l i a Lupinus h a v a r d i i  Mesquite, creeping honey  Prosopis reptans P. glandulosa  •ak, l i v e Texas •cotillo  Quercus v i r g i n i a n a Q. texana Fouquieria splendens  Parthenium, l y r e - l e a f P r i c k l y ash P r i c k l y pear cactus  Parthenium confertum Zanthoxylum fagara Opuntia l i n d h e i m e r i , 0. engelmannii  122.  Sand bur Sapote Sotol• Spiny aster  Cenchrus i n c e r t u s , C. myosuroides Bumelia c e l a s t r i n a D a s y l i r i o n texanum, D. ieiophyllum Aster spinulosus  Tarbush Tasajillo Twisted acacia  Flourensia cernua •ptunia l e p t o c a u l i s Acacia tortuosa  Whitehorn  Acacia c o n s t r i c t a  Yucca  Yucca e l a t a , Y. thompsoniana, Y. torrey Y. r o s t r a t a  Birds Bobwhite Turkey, Rio Grande  Colinus v i r g i n i a n u s Meleagris galopavo intermedia  Mammals Antelope Badger Bobcat Cotton r a t Cottontail Coyote Deer, mule white-tailed Sonora w h i t e — t a i l e d Gray fox Jackrabbit Mountain l i o n Pig, feral Racoon Woodrat, southern p l a i n s  Antilocapra americana Taxidea taxus Lynx rufus Sigmodon hispidus S i l v i l a g u s f l o r i d a n u s , S. auduboni Canis l a t r a n s •docoileus hemionus crooki 0. v i r g i n i a n u s texanus •. v. c o u e s i i Urocyon cinereoargenteus Lepus c a l i f o r n i c u s F e l i s concolor Sus scrofa Procyon l o t o r Neotoma micropus  123.  Appendix B.  Handling trapped and captive peccaries.  The canine tusks of peccaries are capable of i n f l i c t i n g severe wounds.  Therefore i t was necessary to subdue the animals before marking  and measuring were done.  The i n i t i a l and most successful method of subduing  trapped peccaries was to noose them through a hole i n the top of the trap. A 1/8 inch wire cable was f i t t e d to l i g h t 6-foot conduit pipe so that a noose was formed at one end. neck and p u l l e d taut. from apnea.  The noose was placed around the animal's-  A f t e r a short struggle the animal became quiet  I t was then quickly removed from the trap, i t s legs t i e d ,  and i t s snout strapped to prevent use of i t s dangerous canine tusks. The animal could then be s a f e l y handled. I experimented with several immobilizing and t r a n q u i l i z i n g drugs that would permit e f f i c i e n t handling of the animals.  Pen—reared animals  were r e a d i l y t r a n q u i l i z e d with Tranimal o r a l powder (Hoffman-LaRoche). This i s a wide tolerance t r a n q u i l i z e r and was mixed with the p e l l e t e d food and given to the animals several hours before handling.  The e f f e c t i v e  dose i s shown i n Table 1. The t r a n q u i l i z i n g e f f e c t l a s t e d up to 36 hours. During that time, the animal could s t i l l walk, but had l i t t l e coordination and could be handled r e a d i l y .  When i t was necessary to anaesthetize the  animals completely f o r tooth impressions, I put a p l a s t i c bag, containing a chloroformed swab, over the t r a n q u i l i z e d peccary's head u n t i l the animal succumbed.  By j u d i c i o u s use of the chloroform swab, I could keep the animal  immobile f o r a t l e a s t an hour with no apparent a f t e r - e f f e c t s . I used Tranimal mixed with the p e l l e t e d cotton-seed cake b a i t i n the traps, sodium p e n t o b a r b i t a l administered by a hand-syringe to trapped peccaries, and s u c c i n y l c h o l i n e chloride' i n Cap-chur gun darts on free-ranging peccaries.  The successful dosages are l i s t e d i n Table 1. Use of drugs on  trapped peccaries was discontinued because 1) of the necessity of catching the animal before i n j e c t i n g the drug (the small target area made use of Cap-chur darts dangerous t o the animals), 2) the long recovery time unduly exposed the animals to heat p r o s t r a t i o n i n t h e i r i n s e n s i b l e wanderings and to possible predation.  P h y s i c a l r e s t r a i n t of the animals proved to be most e f f i c i e n t .  124.  Table 1 . T r a n q u i l i z i n g and immobilizing drugs and s u c c e s s f u l dosages used on penned and trapped peccaries.  time to (min) effect  Dosage  |recovery  Remarks  Tranimal (Hoffman-LaRoche) - o r a l powder 20.6 mg/lb 39.6 mg/lb l.t 1 .5 gm/gal. food 2.5 gm/gal. food  90  8 hrs,  150 90 60  36 h r s .  Sodium P e n t a b a r b i t a l (Winthrop Lab  36 h r s .  Considerable l o s s of coordination L i t t l e coordination Slight tranquilization Marked t r a n q u i l i z a t i o n , l o s s of coordination  N.Y.) -  Anaesthetized 10.5 mg/lb 25 1 .5 Anaesthetized 60 g.t. 120 11 .3 mg/lb l.t Anaesthetized 145 13.1 mg/lb 1 .5 Anaesthetized 14.1 mg/lb 1 .5 g.t. 120 S u c c i n y l c h o l i n e c h l o r i d e (Sucostrin) - intramuscularly 0.26 mg/lb 0.4 mg/lb  5 3  60 died  Retained jaw movement Dart broke r i b , s p l i t d i a phragm, punctured i n t e s t i n discharged i n lung  125. Appendix C. 1.  Age determination of peccaries.  Young and Adults. Since age i s important i n reproduction, I desired to determine the  age of the animals as accurately as p o s s i b l e . Several age determination techniques have been developed that have a p p l i c a b i l i t y to one or more species, but only tooth patterns and eye lenses have been p r e v i o u s l y assessed f o r age determination of peccaries (Sowls, 1961a; K i r k p a t r i c k and Sowls, 1962; L. K. Sowls, pers. comm.).  In my study  I tested the usefulness of eye lens weights, tooth eruption pattern, tooth wear, and annulations i n the dental cementum as i n d i c e s of age.  In  a d d i t i o n , data on i d e a l weights and body measurements during e a r l y l i f e stages were obtained from captive-born and reared animals.  These growth data are  mainly u s e f u l f o r determining growth rates under good c o n d i t i o n s . The data can then be used as a basis f o r determining the n u t r i t i o n a l adequacy of the wild diet.  These data have been t r e a t e d separately, even though they have  been used to determine the approximate ages of free-ranging and l i v e - t r a p p e d animals.  1.1.  The other three methods w i l l be treated f u l l y  here.  Methods Eye lens weights have been s u c c e s s f u l l y used i n the determination  of age of a v a r i e t y of smaller mammals and the young stages of some l a r g e r mammals.  Friend (1967 a, b, c,) has reviewed the c r i t i c a l methods of pre-  paration of lens material and the species on which i t has been s u c c e s s f u l l y used.  The method used i n my study was s i m i l a r to that of Lord (1959, 1963).  The eyes were removed from the s k u l l and the l e f t lens and the r i g h t e y e b a l l , which was s l i t to f a c i l i t a t e f i x a t i o n , were put i n a v i a l of 10% Formalin and l e f t f o r periods varying from two weeks to 12 months.  P e r i o d i c a l l y the  lenses which had accumulated were removed from formalin', placed i n i n d i v i d u a l v i a l s and dried at approximately 80°C f o r 14 days.  When dry, the lenses were  removed from the v i a l s and weighed to the nearest 0.1 mg. and r i g h t lenses were recorded separately.  The weights f o r l e f t  Damaged lenses were discarded.  I p e r i o d i c a l l y noted tooth progression i n pen-reared animals of known age to e s t a b l i s h the eruption pattern f o r the Texas c o l l a r e d peccary. Tooth impressions were taken on some pen—reared  animals (Flyger, 1958).  Since captive peccaries were fed p e l l e t e d feeds and wear on the teeth i s g r e a t l y a f f e c t e d by the type of food consumed, I did not emphasize examinat i o n of tooth wear i n the captive animals.  126. The age of some l i v e - t r a p p e d young, and a l l those c o l l e c t e d , was determined by comparing tooth patterns with known-age patterns.  The age of  c o l l e c t e d animals over 24 months (completion of the eruption of permanent teeth) was determined by tooth wear c r i t e r i a established by Sowls (1961 a: 499).  These c r i t e r i a are:  s l i g h t wear - - Class 1; wear conspicuous on  Molars 1 and 2 — — Class 2; a l l teeth showing wear — — Class 3; very heavy wear on a l l teeth - - Class 4; and extreme wear with some teeth missing - Class 5.  A l l of the s k u l l s from the peccaries c o l l e c t e d i n Texas were  placed i n a progressive s e r i e s and the l i m i t s of each of the wear classes decided. Annulations i n dental s t r u c t u r e s have received considerable a t tention i n the l a s t few years as an a i d i n determining the age of l a r g e mammals.  Madsen (1967) and Sergeant (1967) have reviewed the l i t e r a t u r e . Low and Cowan (1963) hypothesized that annulations i n mule dder  teeth were caused by both r u t t i n g and food shortage.  Since peccaries under-  go i r r e g u l a r food shortages that vary seasonally and annually, and breed throughout the year, there was some question about adapting the method tp peccaries.  When the teeth were examined, however, annulations were obvious  i n the cementum of some animals, although d i f f i c u l t to i n t e r p r e t i n others. I assessed the method using teeth from animals pen-reared i n Arizona by Dr. Sowls, and i n Texas and at U.B.C. during t h i s study. The f i r s t i n c i s o r was used f o r examination  of dental cementum  annulations because i t i s e a s i l y extracted and i s the f i r s t of the replacement d e n t i t i o n to erupt.  Several canines were sectioned but these proved  of no a d d i t i o n a l value, and were considerably more d i f f i c u l t to prepare f o r examination. The tooth preparation procedure was modified only s l i g h t l y from Low and Cowan (1963) by using 30°/o formic a c i d with 10% formalin added, to d e c a l c i f y the teeth.  Transverse sections were cut at 8 JJ with a rotary  microtome; every twentieth section was taken from the lower l / 5 t h of the root and mounted on a glass s l i d e .  S p e c i a l a t t e n t i o n was paid to obtaining  sections from the area where the dentine f i r s t appears when the tooth i s sectioned from the apex of the root. is thickest.  I t i s u s u a l l y here that the cementum  The sections were stained with H a r r i s Haematoxylin and mounted.  The sections were examined with a microscope using transmitted light.  A blue-green f i l t e r enhanced the v i s i b i l i t y of a n n u l i i n some sec-  tions.  P l a t e 1a shows the method of counting annulations.  The method i s  127. explained more f u l l y i n the f o l l o w i n g d i s c u s s i o n .  Accuracy of the counts  was improved by r e f e r r i n g to other i n d i c a t o r s of age, such as tooth wear c l a s s and closure of the canine root, i n order to e s t a b l i s h the approximate order of magnitude of the number of annulations to be counted. Canine teeth were examined f o r external cementum annulations (Scheffer, 1950), closure of root canal, and length of exposed tusk.  1.2.  Results and Discussion. The lens weights of 157 animals ( i n c l u d i n g 24 known-age animals  from one day to 54 months old) were determined.  The average d i f f e r e n c e i n  weight between the l e f t and r i g h t lenses was 3.5 mg., a d i f f e r e n c e of 0.9% from the mean lens weight, and t h i s was not s i g n i f i c a n t .  There was no  s i g n i f i c a n t d i f f e r e n c e between weights of lenses from males and females. Figures 1a and b show the lens weights grouped by annulationeruption age and by age c l a s s e s .  There was a s i g n i f i c a n t d i f f e r e n c e i n lens  weight between only Age Class 1 and the remainder, and between 1 year olds and those o l d e r .  F i g . 2 shows the lens weight-age r e l a t i o n s h i p of animals  up to 21'.months of age.  A f t e r that age the r a t e of weight increment be-  came so low that i n d i v i d u a l v a r i a t i o n masked the weight gain.  The regression  l i n e of lens weight on age f o r the known-age animals up to 21 months was y = 0.14x - 6.0 (y = age i n months, x = lens weight) with a highly s i g n i f i c a n t c o r r e l a t i o n c o e f f i c i e n t ( r = .98).  The regression of lens weight on tooth  eruption age of a l l of the young animals l e s s than 24 months c o l l e c t e d was y = 0.13x - 6.5 with a highly s i g n i f i c a n t c o r r e l a t i o n c o e f f i c i e n t ( r = .95). The curve f o r lens weights of known—age animals l e v e l l e d o f f by age 24 months ( F i g . 2) to a slope that made the regression u n r e l i a b l e beyond t h i s age f o r age p r e d i c t i o n , even though lens weight continued to increase ( F i g ; 1).  However, because of the l i n e a r r e l a t i o n s h i p i n the younger  animals, the technique appears v a l i d f o r age p r e d i c t i o n before that age. F i g . 1a shows a s i g n i f i c a n t d i f f e r e n c e (P<^ .05) between lens weights of animals 1 year o l d , 2 years o l d , and greater than 2 years o l d . When a l l of the animals older than seven years were'grouped there was a s i g n i f i c a n t d i f ference (P<.05) between them and younger animals ( F i g . 1b).  A larger  sample might show s i g n i f i c a n c e between age c l a s s 2 and 3 and the remainder, but not l i k e l y between classes 4 and 5 because of the high v a r i a b i l i t y i n  128.  Figure 1.  Lens weight d i s t r i b u t i o n by A) age c l a s s and B) annulation age of south Texas peccaries. error at the t  Values shown are: mean, stan  _ l e v e l , and the range.  '.129.  LENS WEIGHT  (mg)  300  200  (n=) AGE CLASS  (26) II  I  300  (25)  (10)  (16)  III  "rv"  V  B  •  200  100  NKl6)(3l6QC(14?)(g)0l2fl£(lO) (ft) (g) ( g f (2) ( 3 ) ( 2 ) ( 4 ) (1) 1  AGE (Mo)  1 2  3  4  5  6  7  10  1  11  T-  12  1  1  1 3 . 14  (21) 1—  15  (:130.  VOLUME  (mm ) 3  210  180 .  150 •  EH  o I—I  w 120 CO  KNOWN AGE PECCARIES l e n s wt= 4fc>.2'/ + b.y$~Tage) age= 0 . 1 4 ' l e n s ) - 6 . 0 1  90  ALL PECCARIES l e n s wt= 5 4 . 8 + 6 . 8 (age) age= .13 ( l e n s ) - 6 . 5  60  r=.95 known age • e r u p t i o n age a 30 5 mo.  10  15  20  25  AGE  Figure 2. Regression of lens weight on age of known-age peccaries 121 months o l d , and ©f a l l south Texas peccaries 124- months o l d . For p r e d i c t i o n of age from lens weight, age i s dependent v a r i a b l e and the appropriate l e a s t squares l i n e s of best f i t are given by the second formula i n each case.  131 .  those c l a s s e s . N u t r i t i o n influences growth of the lens (Lord, 1963; Matschke, 1963; Friend, 1967b), p a r t i c u l a r l y i n the f i r s t phase of post-partum growth (Friend, .1967b; Friend and Severinghaus, 1967).  Since peccaries are born  throughout the year, and food conditions vary markedly from season t D season and year to year, the conceivable d i f f e r e n c e i n lens growth would make the use of the lens weight r i s k y f o r age determination.  However,  i n my known—age sample were three 3.7 month o l d males, whose lens weight varied a maximum of 4.9/o from the mean weight f o r the three animals (mean, D  74.5 mg, range, 70.1 to 78.8 mg, S.D.,  3.1 mg), while the carcass weights  v a r i e d 84°/o from the mean f o r the three animals (mean, 6.6 l b s , to 12.0 l b s ,  S.D.,  4.7 l b s ) .  range, 3.8  Thus the eye lens weight i s much more con-  s e r v a t i v e than the body weight and therefore more accurate f o r age determination.  The same conclusion was a r r i v e d at by Dudzinsky and Mykytowycz  (1961). Ranges of age at tooth eruption i n the south Texas peccaries ( F i g . 3) based on my pen—reared sample, i n d i c a t e that i t i s s i m i l a r to that found i n the Arizona peccaries ( K i r k p a t r i c k and Sowls, 1962), with some v a r i a t i o n . In the south Texas animals, molars  and  erupt about three months l a t e r  than i n the Arizona peccaries, but M^ erupts e a r l i e r , and i t s p o s t e r i o r most cusp i s not f u l l y erupted u n t i l the animal reached 25 months. The only other d i f f e r e n c e of consequence i s the eruption time of lower I .  My  data show that one animal s t i l l has i t s deciduous I ^ present at 15 months, at l e a s t f i v e months l a t e r than i n the Arizona peccaries.  In s i x 14-month  old animals examined, the permanent I„ was i n place but had not been present at 12 months.  Lower PM^i  a n  d PM^ were erupted or erupting i n one a n i -  mal at 10 1/2 months, about f i v e months before eruption i n the Arizona peccaries.  This animal was captured as a baby of two to three weeks.  The  differences i n eruption times f o r the other teeth vary only s l i g h t l y . A f t e r the l a s t molar has f u l l y erupted at about two years o l d , i t was necessary to depend upon s u b j e c t i v e estimation of wear on the cheek teeth to separate age groups i f the age of the animals was determined by tooth wear. The d i v i s i o n between Sowl's (1961a) age classes i s s u b j e c t i v e and i t i s necessary to r e f e r constantly to the standards set f o r d i v i s i o n of the continuum i n t o groups.  Separation of the f i r s t age c l a s s i s f a i r l y o b j e c t i v e ,  and the upper l i m i t of the second wear c l a s s i s only a l i t t l e more i n d e f i n i t e .  132.  FIGURE 3.  Tooth eruption progression f o r south Texas peccaries. Lines i n dicate presence of tooth; heavy portions show range of v a r i a t i o n i n age at which tooth f i r s t appears.  134.  The o l d e r groups are more d i f f i c u l t to separate and assign to age classes because they are based ondegree of wear of a l l of the teeth and unless a s e r i e s of tooth measurements i s taken, as Lowe (1967) has done f o r red deer, i t i s d i f f i c u l t to be o b j e c t i v e i n separation of the groups.  Class 5 i s  separated from 4 on the basis of extreme wear and l o s s of teeth.  In some  animals i t was apparent from other c r i t e r i a that they were not as o l d as a Class 5 group would i n d i c a t e .  Animal P-79, f o r example, probably l o s t a l l of  i t s cheek teeth due to i l l n e s s or disease.  In some animals maloclusion has  r e s u l t e d i n early l o s s of some teeth A v a r i e t y of f a c t o r s , notably food composition, can cause i r r e g u l a r or d i f f e r e n t r a t e s of wearing.  Peccaries i n both south and west Texas  areas consumed foods which are frequently coated with sand or dust p a r t i c l e s . This undoubtedly hastens tooth wear.  In a d d i t i o n , although foods i n both  areas are v e r y - f i b r o u s , the l e c h u g u i l l a and.sotol commonly eaten by west Texas animals are probably more abrasive than the nopal p r i c k l y pear (0. lindheimeri )  commonly eaten by south Texas peccaries. Thus tooth wear i n  west Texas peccaries i s probably f a s t e r , and i f animals were "aged" by the same tooth wear c r i t e r i a i n the two areas, the west Texas peccaries would a c t u a l l y be c h r o n o l o g i c a l l y younger than the south Texas animals i n a given age c l a s s .  The o l d e r age c l a s s e s should r e f l e c t t h i s d i f f e r e n c e to  a greater degree.  The l i m i t e d data i n F i g . 4 do i n d i c a t e the d i f f e r e n c e  i n degree of wear, but since most of the animals from west Texas were l e s s than four years o l d , wear differences would not have had time to become accentuated. Annulations were v i s i b l e i n the cementum of a l l teeth examined, but were d i f f i c u l t to count i n some of them.  As determined from the known-  age animals up to 10 years 5 months, the annulation age i s within one year of the correct age i n the o l d e r animals, and i s more accurate i n the younger animals (Table 1).  The accuracy probably decreased i n animals over 10 years,  but animals.aged to 15 years are probably within 2 years of the correct age. The sequence of deposition of cementum was determined on the animals c o l l e c t e d i n south Texas, and the November-December c o l l e c t i o n from the Black Gap area confirmed the pattern. northern ungulates. permanent teeth.  The discussion w i l l be l i m i t e d p r i m a r i l y to the  Annulations are l a i d down during the winter between  October or November and March or A p r i l . 'summer cementum i s v i s i b l e . 1  I t i s the same as f o r more  By early May, a t h i n deposition of  Lamellae, as described by Nishiwaki, et a l .  135.  Figure 4.  Comparison of age determined by dental annulations (x-axis) and wear classes f o r south and west Texas peccaries. Sowl's Wear Classes •- LZl 1-  2-  345-  m  g H  a  •  AGE I N YEARS  137.  Table 1.  Comparison of known-age and annulation age of peccaries penreared by L. K. Sowls i n Arizona, and during t h i s study at U.B.C. and the Welder Refuge.  Anim.a No.  Birth Date  Death Date  Known Age  S- 657 S- 671 S-1142 S-1152 S-1155 S-1159 S-1435 S-1535 S-1566  4-65 9-65 . 1-56 7-59 6-57 11-62 6-55 7-58 5-57  5-66 8-67 5-66 7-61 5-66 9-64 1-65 6-65 1-62  i y 1m 2y 11m 5m 10y 2y 8y 11m i y 10m 9y 7m 6y 11m 4y 8m  Pc-154 Pc-155 Pc-156 Pc-157  Spring/65 12-65 4-66 6-65  8-67 8-67 8-67 8-67  Notes:  a  -  b  —  + ++ +++  c  -  d  -  2y iy iy 2y  No. o f Annuli  8m 8m 9m 2m  d  d 1+ 9 6+ 4  Annulus Age 1 1/4 2-3 9-11 2 1/2 8 3/4 1-2 9-10 6- 7 4- 5  0+ 9+ 2+  b  8 +  d  d 1++ 0++ 1++  2 +  d  yr yr yr yr yr yr yr yr yr  l . t . 3yr 1 1/2 y r 1 1/2 y r 2 yr  c Comment F P,A F P 4th  forming  F F  S - s e r i e s from Arizona, Pc- and J - s e r i e s from Texas and U.B.C. Indicates t h i n deposition of summer cementum f o l l o w i n g annulus Indicates considerable deposition of summer cementum Indicates s u f f i c i e n t summer cementum deposited that next annulus might be i n process of form ing at outer edge of cementum P-poor d e f i n i t i o n of a n n u l i ; F - f a i r d e f i n i t i o n M-moderately good; G-good; P-G-some poorly, some w e l l defined; A—several good annuli on canine root. F i r s t annulus i n eruption cementum.  138. (1958), are v i s i b l e throughout the summer cementum i n some of the teeth.  In  some years, i n some teeth, double a n n u l i are formed as described by Low  and  Cowan (1963), with the l e s s intense annulus f o l l o w i n g the intense annulus. Although peccaries breed throughout the year, there i s a-, major breeding season s t a r t i n g from December to February, and i t i s possible the " r u t " l i n e i s caused i n peccaries by hormonal changes associated with breeding.  Further,  annual food a v a i l a b i l i t y i n peccary habitat i s r e s t r i c t e d by moisture conditions, which vary seasonally as w e l l as annually, and therefore are not consistent enough to cause an annual deposition occurring at approximately the same time each year.  Thus, i t would appear that annulations i n dental cementum are  caused by a fundamental annual metabolic rhythm. I t i s i n t e r e s t i n g to speculate that i n those instances where a strong annulation i s l a i d down, i t may or food shortage.  have coincided with a winter drought  However, i n some animals (eg. P—12,  P l a t e 1b)  strong  a n n u l i are l a i d down every year, whereas i n other animals (eg. P-14,  Plate  1c) weak a n n u l i are formed every year.  P-81,  In s t i l l other animals (eg.  P l a t e 1d) , a s e r i e s of a n n u l i are intense followed by a s e r i e s of weak annuli.  I t appears that deposition of the annuli are not under the strong  i n f l u e n c e of climate since the deposition pattern does not seem to be r e l a t e d to the c l i m a t i c pattern. There i s a change i n s t r u c t u r e i n the f i r s t l a y e r of "summer" cementum s i m i l a r to that described f o r mule deer by Low and Cowan (1963) (Plate 1a). ing  I t i s probable that the more c e l l u l a r portion i s deposited  dur-  the period of r a p i d eruption and the l e s s c e l l u l a r portion deposited  r a p i d eruption i s complete (Orban, 1944).  after  Rapid eruption i s u s u a l l y com-  p l e t e w i t h i n a couple of months of the time that i t breaks throught the gums. The thickness of the f i r s t summer depostion v a r i e s considerably from animals born i n the spring to those born i n the f a l l .  A spring born animal  gets i t s permanent f i r s t i n c i s o r i n the l a t e spring or e a r l y summer, thus the deposition of summer cementum i s r e l a t i v e l y t h i c k by the time the f i r s t annulus i s formed.  Conversely, the permanent f i r s t i n c i s o r of an autumn  born animal erupts i n the autumn or winter, and an annulation would be posited almost immediately.  de-  In some cases, the f i r s t annulation i s present  i n the c e l l u l a r portion of the cementum deposited p r i o r to completion of the r a p i d eruption period. In counting annuli i n deer teeth, the changeover from c e l l u l a r to  139.  Appendix C. P l a t e 1.  Annulation i n tooth cementum. a.  The method of counting annulations i n the cementum of the f i r s t i n c i s o r . The v e r t i c l e arrows show s i x d i s t i n c t and one i n d i s t i n c t a n n u l i . The outside annulus was c l e a r l y evident i n other areas of the s e c t i o n . An eighth annulus was also v i s i b l e close to the dentino-cementum (D-C) i n t e r f a c e i n other parts of the s e c t i o n . "E" i s the zone of change from the c e l l u l a r r a p i d eruption to the l e s s c e l l u l a r posteruption cementum. Surface eruption of t h i s tooth s t a r t s at 13 to 15 months o l d . The f i r s t annulus v i s i b l e here.was judged to have s t a r t e d to form at 2 1/2 years (November of December) and would have been completed by 34 to 35 months (March). The l a s t annulation would have been formed by j u s t under 9 years and the 2 months from completion of annulation deposition to death give an estimate of age of 9 years. The animal i s a known-age Arizona peccary (S-1155) known to be 8 years 11 months o l d .  b.  Strong annulations i n the cementum of an 8-year o l d south Texas female (P-12) k i l l e d i n May. Seven a n n u l i are v i s i b l e and s e v e r a l of these are double. The dentine i s at the bottom. The excessive c e l l u l a r i t y of the summer cementum f o l l o w i n g the fourth annulus i s unusual;  c.  Weak annulations i n the cementum of a 6—year o l d south Texas female (P-14) k i l l e d i n June. The dentine i s at the lower r i g h t . Five a n n u l i are v i s i b l e .  d.  F a i n t and strong annulations i n the cementum of a 10-year o l d female (P-81) k i l l e d i n May.  1.40.  141 .  l e s s — c e l l u l a r cementum i n the f i r s t summer can be mistaken f o r an annulus unless constant care i s taken.  This i s also a problem i n peccaries (Plate  1a) with the added d i f f i c u l t y that an annulus could conceivably coincide with the changeover of cementum types.  Hence, the region between the  dentino—cementum i n t e r f a c e and the f i r s t annulus outside the changeover r e gion of cementum types must be c a r e f u l l y s c r u t i n i z e d to determine presence or absence of an annulus.  The tooth breaks through the gum at 13 to 15  months and t h e . f i r s t annulus could be deposited anytime between about 10 months and 22 months. To determine the age, I estimated the age at the time the f i r s t annulation i s deposited and added the number of annuli to that age. For example, i f the f i r s t annulus i s close to the dentino—cementum i n t e r f a c e i n the 'pre-eruption' cementum, then the age at the time of formation of the f i r s t annulation i s between 10 and 16 months. The t o t a l number of annuli then represents the approximate age to the time of deposition of the l a s t annulation.  I f the f i r s t annulation i s outside the changeover zone from  c e l l u l a r pre-erupted to r e l a t i v e l y a c e l l u l a r post-erupted cementum, then the number of months between eruption time and annulation deposition was estimated from the amount of intervening cementum.  This time, plus two  mon ths ( average number of months over one year that the f i r s t  incisor  erupts), was then added to the t o t a l number of annulations present to a r r i v e at the age at time of deposition of the most recent annulation. The correct age i s then determined by adding the number of months elapsed between time of death and March (the time at which summer cementum deposition starts). The l o c a t i o n of the f i r s t annulus i s an i n d i c a t o r of the approximate time of the year that the animal was born.  I f i t i s close to the zone  of change from r e l a t i v e l y c e l l u l a r to r e l a t i v e l y n o n - c e l l u l a r cementum, then the animal was born i n the f a l l or l a t e summer.  I f i t i s relatively dis-  tant from the eruption zone, then i t was probably born i n the spring. The s e r i e s of known—age teeth (Table 1) show that there i s some discrepancy i n the age determined from annulations when compared to the known age. However, t h i s occurs i n those animals that have poorly defined a n n u l i (eg. P l a t e I c ) . In those animals which have w e l l defined annuli (eg. P l a t e lb) the assessment of age i s quite accurate.  In no case does  the determined age depart by more than one year from the known age. Annulations were only moderately easy to i n t e r p r e t i n about 66°/o of the teeth from Texas peccaries. bably quite accurate.  In these animals the assessed age i s pro-  In the other 3 4 % d i f f i c u l t y of counting annuli varies  142.  from d i f f i c u l t (17.5%) to almost impossible (16.5%) to count. The canine tusks of peccaries are open—rooted and are continuously being forced.upward by deposition of d e n t i n a l cones i n s i d e the root i n the manner of the Phocids (Laws, 1962).  As a r e s u l t , the canine root canal of  the known-age peccaries progresses from a wide open s h e l l a t eruption, to greatest s i z e of opening at 2 to 3 years when the tooth has reached i t s maximum s i z e , to almost closed at about 10 years.  The root of the canine o f  a 10 year 5 month o l d Arizona peccary was only s l i g h t l y open.  Several of the  south Texas peccaries c o l l e c t e d from the King Ranch had canines i n which the root canal was closed.  These animals were a l l determined by annulation count  to be over 12 years o l d , except f o r P-113. worn down and the root was severely eroded. years i s probably conservative.  This animal's canine was extremely I t s estimated age of 10 o r 11  The r e s u l t o f the growth pattern of open-  rooted teeth i s a pattern s i m i l a r to that drawn by Godin ( i n Mosby, 1963: 153, F i g . 6. 23) i n the cementum.  In peccary canines, only the f i r s t two or  three r i n g s are obvious along with numerous l e s s e r annulations on the surface o f the root. Measurement of the length o f the canine exposed above the gum has been suggested as a possible i n d i c a t i o n of age.  This i s not f e a s i b l e be-  cause the tooth reaches i t s maximum exposed length at three to four years. Thereafter, the r a t e o f wear exceeds the rate of eruption, and the exposed length  decreases. I t i s apparent from F i g . 4 that age determined from annulations  generally f a l l s i n t o the groups determined from tooth wear, with the except i o n o f animals o l d e r than seven or eight years.  These animals are i n age  classes 4 and 5, and they f a l l i n these groups i n an i r r e g u l a r fashion.  Thus  i t i s probable that age classes 4 and 5 should be more r e a l i s t i c a l l y  treated  as a s i n g l e group when age associated characters are being examined.  How-  ever, When condition—associated characters ( i . e . dependent upon the animals a b i l i t y to obtain food) are being examined, i t could be u s e f u l to recognize f i v e age classes ( F i g . 4 ) . Age Class 1 contains animals that are between two and three years old.  Age Class 2 contains animals that are between three and approximately  f i v e years o l d .  Age Class 3 contains animals that are f i v e to seven years o l d ,  and Classes 4 and 5 contain animals o l d e r than seven years up to about 15 years.  143. '1.3.  Conclusions The most p r a c t i c a l and accurate methods of determining  of peccaries involved the teeth.  the age  Eruption patterns are e a s i l y obtained and  accurate w i t h i n two months f o r animals up to 25 months o l d (the age at which the l a s t permanent tooth completes eruption). annulations provide a means of determining  Dental cementum  age, accurate w i t h i n one year,  for animals that are older than one year, i n those animals i n which annuli are c l e a r l y defined.  In animals with poorly defined a n n u l i , consideration of  age c l a s s , canine root closure and lens weight a s s i s t i n the i n t e r p o l a t i o n of the a n n u l i , and used j o i n t l y a r e l a t i v e l y accurate age can be determined. For young animals i n the r a p i d growth stage l e s s than 24 months o l d , the lens weight appears useful f o r age determination.  A regression l i n e y =  0.15x - 6,6 was established f o r the known-age animals l e s s than 24 months old. 2.  Age Determination Of Foetal Peccaries Two methods of estimating age of foetuses were used. Growth  curves of demestic p i g foetuses ( U l l r e y , et a l . , 1965) and b l a c k t a i l deer foetuses (Thomas, 1970) drawn so that the gestation periods (114 and 203 days, r e s p e c t i v e l y ) and crown-rump lengths (at 5 and 4 i n t e r v a l s r e s p e c t i v e ly) were p l o t t e d i n the same i n t e r v a l showed that the growth curve during the l a s t 75°/a of the gestation period fallowed s t r a i g h t l i n e s which almost coincided' ( F i g . 5 ) . No information was a v a i l a b l e on the i n i t i a l 25°/o of the gestation period.  These species were chosen because they  represented  l i t t e r s i z e s and gestation periods e i t h e r side of peccary l i t t e r s i z e and gestation period.  I assumed that i f the curves f o r these species coincided,  then the curve should be a p p l i c a b l e to peccary foetuses. Peccary gestation time of 144 days (Sec. 4.6,) and the crown-rump length at p a r t u r i t i o n (10 inches) were p l o t t e d i n the same i n t e r v a l s as f o r the other two species.  One known-age l i t t e r of. peccaries obtained at an :  average crown-rump length of 6.8 inches at 105 days coincided almost perf e c t l y with the curves f o r the other two species ( F i g . 5 ) . Foetal age was then determined by taking the crown-rump length of the foetuses and l o c a t i n g i t s corresponding age on the chart. A second method employed the weight of the foetuses.  Hugget and  Widdas (1951) determined from a comparative a n a l y s i s that f o e t a l weight of 1 /3 mammalian species could be determined from the formula W = a ( t - t ), where o ' W i s foetus weight, 'a ' i s the s p e c i f i c f o e t a l growth v e l o c i t y , ' t ' i s the :  L E N G T H  = Figure 5. Crown-rump growth curve^ o f . f o e t a l domestic p i g and b l a c k - t a i l e d deer, plotted i n the same i n t e r v a l , and used f o r p r e d i c t i n g the age of f o e t a l (peccaries..:; ' •  145. g e s t a t i o n age, and 't  1  i s the early portion of pregnancy before "stable"  environmental conditions provided by an adequate symbiotic r e l a t i o n s h i p " are e s t a b l i s h e d . They have estimated that 't ' f o r species with a gestation o period of 100 to 400 days i s 0.2x  (gestation period) and 0.3x (gestation  period) f o r a gestation period..of 50 to 100 days.  Hence, I used a f a c t o r  of .25x (gestation period), and determined that f o r . p e c c a r i e s , 't ' i s °1 /3 38 days.  'a' i s determined by s u b s t i t u t i n g i n t o the formula a = W  /t-t^,  the values of 'W and ' t ' at any known time during g e s t a t i o n . Thus, at p a r t u r i t i o n 'W = 728 gms  (Table 10), ' t ' = 144 days and 'a' =  .086.  However, i f the data f o r the 101 days o l d foetuses are s u b s t i t u t e d , then 'a' = .098. The mean of these two s p e c i f i c growth r a t e s f o r peccaries i s .092. I f these values are then used to determine ' t ' i n the transposed formula, 1 /3 t = (W  /.092) + 38, the approximate gestation age of the foetuses can be  determined.  This has been done to a r r i v e at the post-conception age  (weight)  i n Table 2. A p p l i c a t i o n of the two methods using the weight and length of the foetuses of U.B.C. female Pc-168, r e s u l t s i n ages of 121 and 125 days, r e spectively.  The r e s u l t s agree f a i r l y c l o s e l y f o r the two methods.  Rela-  t i v e to the age determined from the body length, age determined from body weight i s over—estimated i n early gestation and underestimated i n l a t e g e s t a t i o n . At just over 100 days, the r e s u l t s are about equal. I have estimated the ages of foetuses c o l l e c t e d during the study from crown-rump length and from body weight.  Crown—rump length has been shown  to have a more precise.' r e l a t i o n s h i p to foetus age than does body weight" (Ommundson, 1967). Table 2.  The ages established f o r the foetuses are shown i n  The gestation age derived i s r e f e r r e d to as post-conception  (length) and post conception age (weight), r e s p e c t i v e l y .  Several foetuses  were c o l l e c t e d that were l a r g e r than average post-parturants. occurred, the foetuses were aged as 'term'.  age  Where t h i s  In one case, the post—conception  age (length) was term, whereas the post-conception age (weight) was only 105 days.  No explanation i s a v a i l a b l e f o r the d i s p a r i t y .  In another case,  the female foetus of a set of twins was 382 grams, and the male was 847 grams. Using the means f o r both weight and length, the age was estimated at 130 and 137 days.  I t was evident from the morphology of the foetuses that  they were very near term. l e d down the age estimated.  Thus the extremely slow growth of the female p u l Such cases of extremes were very few.  Post-  conception age l e s s than 50 days i s extremely inaccurate and not to be r e -  146.  Table 2.  Estimate of age of foetuses from crown-rump length and weight (see t e x t ) . Post-conception |y| Age (days) °ncep' x Length wt. length (cmj 19.25 114 116 Dec 24/64 21.6 142 120 Dec 20/64 22.2 125 128 Dec 15/64 28.6 146 Term Dec 21/64 25.0 133 141 Jan 13/6^5 4.1 57 46 May 6/65 11.5 84 78 Apr 8/65 134 24.5.. 138 Feb 16/65 1.4'' 44 20-30 Jun 7/65 13.9 93 87 May 25/65 20-25 Aug 1/65 14.0 93 88 May 29/65 19.1 111 112 May 26/65 20.8 115 121 May 20/65 19.9 115 116 May 22/65 26.0 128 Term Sep 19/65 7.7 72 61 Nov 30/65 13.4 95 85 Nov 6/65 12.6 87 82 Nov 16/65 62 Jan 4/66 26.5 105 Term Nov 26/65 22.4 124 128 Nov 25/65 — 53 Mar 26/66 24.3 130 137 Jan 6/66 12.8 86 84 Mar 22/66 14.1 89 Mar 18/66 19.4 113 108 Mar 19/66 11.4 84 77 Nov 15/66 — — 106.0 Dec 28/66 — 52 1/67 Apr - — 114.6 Jan 27/67 — — 93.4 Mar 4/67 5.5 60 52 Apr 20/67 12.7 88 83 May 27/67 22.1 121 127 Jan 12/68 105 17.1 102 Feb 27/68 23.0 124 131 Oct 24/65 Known —2 days 13.4 90- -86 days Mar 30/66 1 .8 10- -20 days Jan 1/67 B  c  Sow P6 P8 P1D P12 P13 P14 P17 P18 P21 P28 P31 P32 P34 P35 P42 P54 P56 P57 P60 P67 P71 P74 P79 P81 P95 P98 P111 P119 P127 P130 P133 P139 P140 Pc154 Pc168 Pc180 P66 Pc181 WT15 BG 67-1 Note:  foetuses 2 2 1 1 1 1 3 2 2 2 1 2 2 2 2 2 2 2 2 2 2 2 1 2 3 2 1 1 2 2 2 1 2 1 2 3 2 2 2 1  x wt. (gm) 339.6 431 .8 515.2 972 665 5.2 74.1 691 .5 .17 130 127 305.6 358.3 357.3 563 31.4 141 .5 93.0 10.7 234.7 494.5 2.7 '614.5 87.9 —  —  265 77.5 245 2 349.9 132.8 8.8 96.6 440 237.3 497.8 4 c e l l stage 111 .3 1 .2  a- the mean conception date i s the approximate date of conception determined by backdating of the f o e t a l ages derived from the two methods.  147. l i e d upon, because t h i s l e v e l f a l l s below the steady growth phase of Hugget and Widdas (1951). With the approximate gestation age established, the corresponding conception date was determined by subtracting the gestation age from the date of c o l l e c t i o n .  This has been done i n Table 2.  148. Appendix D. Table 1. A g e - s p e c i f i c weight and body measurements of peccaries c o l l e c t e d i n south Texas. (See notes f o l l o w i n g Table 2.) Measurement  Age (years) 1-1 .9 Live weight 2-2.9 (pounds) 3-3.9 4-4.9 5-5.9 6-6.9 7-7.9 8-15 3-15 Carcass weight 1-1 .9 2-2.9 (pounds) 3-3.9 4-4.9 5-5.9 6-6.9 7-7.9 8-15 3-15 1-1 .9 Total length 2-2.9 (inches) 3-3.9 4-4.9 5-5.9 6-6.9 7-7.9 8-15 3-15 Girth 1-1 .9 2-2.9 (inches) 3-3.9 4-4.9 5-5.9 6-6.9 7-7.9 8-15 3-15 1-1 .9 Hind l e g (inches) 2-2.9 3-3.9 4-4.9 5-5.9 6-6.9 7-7.9 8-15 3-15  Males 95% C.I. n 44 2 45 3.5 11 48 6.9 5 6 48 5.8 52 4.4 8 52 8 4.8 53 2 53 2.5 10 52 1,7 39 27 1 11 30 2.8 32 4 9.1 32 5.1 6 7 36 4.7 35 8 2.8 2 38 2.4 36 2.0 10 35 1 .4 37 1 36 0.6 11 38 37 2.1 4 6 38 1 .3 39 8 1 .4 38 1 .3 8 2.6 2 38 39 9 0.9 0.5 38 38 1 24 23 0.8 10 23 1.1 4 6 22 1 .2 24 8 1 .4 23 8 1 .4 22 2 1.1 24 8 1.1 24 0.6 37 6.7 3 1 .5 7.1 0.2 11 7.1 0.2 4 6 7.0 0.4 7.3 0.1 8 7.3 0.2 8 7.3 2 1 .1 9 7.3 0.1 7.2 0.1 38  X 40 44 49 48 51 53 56 52 52 25 28 30 34 32 32 35 32 32 37 37 38 40 39 39 37 39 39 20 22 22 24 23 23 24 22 23 7.2 7.2 7.2 7.3 7.2 7.3 7.4 7.3 7.2  Females 95% C.I. n D i f f . 5 7.8 .2 4.6 7 1 .7 4.9 7 1 .0 5.5 4' 0.1 5.1 11 1 .7 4.1 6 0.3 2 3.0 2.2 19 0.9 1 .6 49 0.3 4.8 6 2.0 2.5 8 2.7 3.8 7 2.1 5.6 4 2.0 3.4 11 3.7 3.0 6 3.4 9.3 2 3.1 2.3 18 5.1 1 .2 46 2.9 1 .7 7 0.3 .7 7 0.6 1 .5 7 0.8 4 1 .8 1 .4 11 0.3 1 .5 1 .3 6 0.9 2 1 .4 1.1 0.6 18 0.4 0.4 48 0.7 0.9 7 3.4 6 0.4 1 .2 1 .7 7 0.3 4 2.0 1 .0 0.8 11 .11.1 6 0.7 1 .9 2.6 2 2.3 0.7 17 1 .5 0.4 47 1 .4 0.1 7 0.5 0.1 8 0.1 0.3 7 0.1 0.2 4 0.3 11 0.1 0.1 0.1 6 0 0.4 2 0.1 18 0 0.1 0.1 48 0  Prob. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. .08 n.s. .01 .01 n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. .05 n.s. n.s. n.s. .01 n.s. n.s. n.s. .01 n.s. n.s.s n.s.s n.s. n.s. n.s. n.s. n.s. n.s. n.s.  149. Appendix D. Table 2. Age-specific weight and body measurements of peccaries c o l l e c t e d i n west Texas. Measurement Live weight (pounds)  Carcass weight (pounds)  Total length (inches)  Leg length (inches)  Note:  a b — c -  Age (years)  X  1-1 .9 2-2.9 3-3.9 4-4.9 3+  Males 95% C.I.  n  45 40 46 39  7.2 12.7 17 5.  3 2 3 4  1-1 .9 2-2.9 3-3.9 4-4.9 5-5.9 6-6.9. 7-7.9 8+ 3+  27 32 28 32 33  3.6 1.8 4.6 6.3 3.5  26 31 28 31 30 31  2.4 2.2 7. 3.9  40 36 33  15 1 .9  14 22." 3 3. 8 0 1 4 27  34 31  8.5 1 .7  1-1 .9 2-2.9 3-3.9 4-4.9 5-5.9 6-6.9 7-7.9 8+ 3+  35 38 39 37 37  1 .4 0.9 4.4 5.0 1 .6  14 21 3 3 8  1 .4 1 .0 5.2 2.1  40 38 38  4.2 0.8  1 4 27  36 37 37 39 40 40  1-1 .9 2-2.9 3-3.9 4-4.9 5-5.9 6-6.9 7-7.9 8+ 3+  7.6 7.4 7.1 7.8 7.6  0.2 0.1 0.3 . .7 .2  14 22 3 3 8  .1  1 4 20  9  7.5 7.4 7.5  Females 95°/o C.I. n  L_  D±ff .  r,  2. 7.  n.s. n.s.  7.  n.s.  12 14* 4 6 2 3 0 4 25  0.7 1.1 0.6 1.6 3.5  n.s. n.s. n.s. n.s. n.s.  1 .8 2.5  n.s. .01  4.8  11 14 4 6 2 3  1 .0 0.9 2. 1 .9 3.  n.s. n.s. n.s. n.s. n.s.  38 38  2.8 0.9  4 26  0.7 0.2  n.s. n.s.  7.6 7.6 7.6 7.4 7.2 7.6  0.2 .1 , .1 .3 2.5 0.9  12 16 3 6 2 3  0. 0.2 0.5 .4 .4  n.s. n.s.s n.s. n.s.  7.4 7.5  .1  4 25  0 0  x"  43 43 47 46 46  3.8 17 7.  9.3  1 2 2 3 5  b  , C  Prob. ..  Values given are the mean, the 95°/o confidence I n t e r v a l and the sample s i z e , difference. p r o b a b i l i t y of d i f f e r e n c e being s i g n i f i c a n t .  Appendix E. Spermatogenic a c t i v i t y of a selected s e r i e s of testes from the c o l l a r e d peccary. . . ., a Weight Date Animal Coll. No. Testis South Texas and pen--raised peccaries 1 day Pc174 Jan/69 1 day Pc177 Feb/69 ,07gm 3 months P-52 Nov/65 1 .0 3.7 mo. Pc158 Aug/67 2.6 3.7 mo. Pc159 Aug/67 0.7 7 mo. Feb/66 2.0 P*55 P-62 7 mo. Mar/66 3.0 P-83 8 mo. May/66 6.0 10 mo. P-70 Mar/66 6.5 9 mo. P-128 Apr/67 6.5 P-109 Aug/66 11 mo. 9.8 1.5. y r . Pc156 Aug/67 15.7 P-16 Jun/65 1.8 y r . 10.0 Pc155 Aug/67 18. 1 .8 P-131 May/67 18.7 2.2 22.5 P-137 Jun/67 2.2 P-144 2.2 Jun/67 12.7 Sep/65 14. 2.5 P-41 Jun/65 18.5 3.5 P-19 P-120 Feb/67 13.6 3.8 P-63 Mar/66 16.1 4.0 P-116 Oct/66 16.3 4.5 Aug/65 P-29 16.1 4.7 P-112 Aug/66 16.1 4.8 Sep/65 21.9 P-38 5.8 P-59 Feb/66 19.2 5.8 6.2 P-149 Jul/67 22.5 P-106 Jul/66 17.4 8.2 P-51 Nov/65 a8.6 8.8 P-126 Mar/67 25.9 9.2 P-5 l e f t Apr/65 31 .7 12.0 right 12.9 P-86 May/66 14.0 16.8 Age  T.I  b  0.023 0.16 0.55 .32 .52 .54 .92 .98 1.-1 1 .3 2.1 1 .2 2.7 2.7 3.0 1 .8 1 .9 2.5 1.9 2.5 2.3 2.3 2.2 3.0 2.7 3.0 2.6 2.5 3.4 3.1 2.3  c Spermatogenesis -cytes -tids sperm no no no v.f. v.v.f. few few mod. mod. few mod. num. num. mod. mod. mod. num. num. mod. mod. num. num. num. num. num. num. num. num. num. num..num. mod. num.  no no no no no no no no few v.f. few mod. mod. num. mod. mod. num. num. num. mod. num. num. num. num. mod. num. mod. num. mod. num. num. mod. num.  0 0 0 0 0 0 0 0 9.2 0.2 35.6 55.2 28.7 60. 95.4 90.6 64.4 81 .2 98.2 57.8 109.4 88.8 95. 70.4 38.0 109.2 75.2 123.7 77.0 97.2 155 60.6 75.8  Tubule *. diam. 0  percent tubules  52.9 u 55.9 56 71 .4 60 67 78 115 130 123 192 165 156 201 211 160 147 203 200 187 188 160 196 168 210 201 160 212 201 203 181 154 182 (cont'd....)  30 41 60 29 35 40 38 30 39 39 59 80 56 67 70 74 73 65 70 81 53 65 82 60 62 86 76 80 61 76 54 26 81  Appendix E (cont'd) WeightAnimal Date Coll. Testis No. West Texas peccaries Jun/66 10.7 2.0 y r WT-14 14.6 Sep/66 2.9 WT-16 Jan/66 9.6 ad.(old) WT-2 9.2 WT-1 Nov/65 -.10.5 Age  9  5. (est.) BG5-25 1.3 y r BG5-7 Notes:  Dec/65 Nov/65  17. 6,.0  c Spermatogenesis —cytes -tids sperm  Tubule^ diam.  1 .4 2.0 1.3 1 .4  num. num. num. num.  num. num. num. mod.  38.8 103 80.5 40.4  198 191 205 191  52 68 66 87  2.3 O.S  num. num.  num. mod.  78.0 . 24.6  226 154  52 50  T.I.  b  percent tubules  a - P c denotes pen-reared animal ID —• T e s t i s index = T e s t i s weight Hind foot length c - Spermatocytes include both primary and secondary; abbreviations are: no = none, v.v.f. = occasional, v . f . = very few, mod. = moderate, num. = numeroussperm counts are the average number/tubule cross section determined from f i v e tubule cross s e c t i o n s . d - tubule diameter i s the average diameter of f i v e tubules; i n microns. e - proportion of t e s t i s composed of tubules; determined with microscope occular g r i d .  8  152. Appendix F.  A g e - s p e c i f i c s i z e of ovaries and several ovarian s t r u c t u r e s .  In these t a b l e s , ovaries from sows l e s s than two weeks pregnant were placed with non-pregnant animals because i t i s d i f f i c u l t to a s c e r t a i n whether a sow i s pregnant or not pregnant during the f i r s t two to three weeks of pregnancy.  Their corpora l u t e a are s t i l l r e l a t i v e l y s m a l l .  Also, included with the non-pregnant sows were those which had degenerating corpora l u t e a .  In one case the sow was only about 12 hours post-partum and 3  the corpora were s t i l l 500 mm . These corpora add considerable v a r i a b i l i t y to the s i z e of the ovary.  Appendix F. Table 1. Age-specific weights and volumes of ovaries and ovarian structures of pregnant and non—pregnant south Texas peccaries. Age (years)  Preserved Ovaries Wt. (gm) X  NON-PREGNANT Foetal .028 <1 .4 1-1 .9 .7 2-2.9 .8 3-3.9 1 .0 4-4.9 1.1 5-5.9 1.1 6-6.9 0.9 7+ 1.1 ALL 2  SE .007 .1 .1 .1 .2 .2 .3 .2  Sectioned Ovaries Vol ( mm )  Preserved Ovaries Vol (cc•) n  X  SE  n  8 (7) (5) (4) (2) (4) (1) (6)  .6 .7 .9 1 .0 1.1 1 .2 1 .0 1.1  .1 .1 .1 .2 .2 .3  (8) (7) (5) (4) (2) (4) (1) (6)  .2  X  SE  14 4 245 81 368 52 537 89 577 148 747 171 650 147 494 494 34  Medull 5\ Vol (mrr )  n  X  (4) (8 (7) (5) (4) (2) (4)  0.7 97 144 185 126 209 126 88 85  (0  (6)  SE  3 14 18 35 31 27 18  n  Lgst Fo VVol . (mm )  Lgst CL Vol. (mm ) X  (4) (8 0.4 (7) 190 (5) (4) 157 (2) 77 (4) 86 (1) 43 (6) 93  n  SE  140 12 65 68  6.2 9.1 o: 13.4 (2] ( 3 : 22.9 6.2 (2: 19.3 (  53  X  n  SE  1 .5 1 .8 2.5 7.8 .9 4.5  (5) (7) (5) (4) (2) (4)  1 .4  (4)  1  (6)  6.2  yr.N.P.I.0  .1  (22)  1 .0  .1 (22)  570  44 (22)  134  14  (22) 117  35  (14) 13.6  PREGNANT 1-1 .9 2-2.9 1 .6 3-3.9 2.0 4-4.9 2.3 5-5.9 2.5 6-6.9 2.1 7-7.9 2.0 2;3 7+ ALL 2.2 Preg.  .1 .3 .2 .1 .1 .1 .1  (2) (2) (2) (7) (5) (2) (13)  1 .6 2.0 1 .9 2.6 1 .9 1 .7 2.2  .3 (2) .4 (2) .1 (2) .2 (7] .1 .2 (2) .1 (13)  989 862 1338 1317 1241 1241 1236  204 (2) 226 (2) 146 (2) 109 7 104 5] 112 (2) 76 (13)  125 157 115 121 110 89 125  21 64 18 24 21 8 10  (2) 467 (2) 329 (2) 688 669 ? 5] 653 (2) 620 (13) 575  67 126 187 55 103 92 51  (2) 12.9 (2) 7.24 (2) 4.6 165 ( ) (5 21 .9 (2) 9.05 (13) 10.0  .9  (1) (11)  .1  (33)  2.2  .1 (33)  1221  47 (33)  121  8  (33) 594  33  (33) 13.0  2.4  (28)  7  2.2  (21)  .9  (2)  .8 8.5 5.9  (2)  0) i) 7  5  Appendix F. Table 2. Age s p e c i f i c weights and volumes of ovaries and ovarian s t r u c t u r e s of pregnant and nonpregnant west Texas peccaries. Preserved Wt. Ovaries  Preserved V o l . Ovaries  issl  Acre.  SE NON-PREGNANT 1 0.3 1- 1 .9 0.6 2- 2.9 0.7 3- 3/9 0.7 4- 4.9 1 .2 5- 5.9 1 .3 6-6.9 1 .2 7+ 0.9 ALL 2 y r . NP 0.9 PREGNANT 2.0 2-2.9 4-4.9 1 .6 7+ 1 .4 All 1 .7 Preg.  V o l . Sectioned Ovaries (mm )  SE  .04 (4) .1 .1 (8) .2 (2) .2 (4) .3 (2) (2)  (0.  111  .1 (20)  .1 .1 •1 •3 .1 .1 •8  0.9  .1 (23)  2.3 1 .5 1 .5  (4)  1.8  0)  SE  0.4 0.7 0.7 0.8 1.1 1 .2 1.1 0.9  (2) (1)  V o l . Medulle (mm )  (4) (4) (8) (2) (4) (2) (2)  LU  200 355 399 405 604 616 613 518  28 10 80 149 51 126 347.  511  50  (1) (1)  111  1081 750 781  .3 (3)  923  SE (3) 93 (4) 179 120 (2) 50 (4) 187 (2) 47 (2) 81 79  M  111  27 41 25 22 57 22 2  V o l . Lgst^ F o i l (mm ) SE  SE 3) 4) 7) 2) (4) (2) (2)  HI  232 241 182 306 524 145  95 71 31  (6) 0) (4) (2) (1)  III  1 .9 10.5 8.0 7.9 16.7 7.5 9.9 22.6  (19) 114  18 (19)  243  46 (15)11  (2) 145 (1) 91 102  (2) (1)  584 514 628  86  (2) (1)  9.1 7.7 9.7  577  42 (4)  8.9  HI 142  V o l . Lgs;t. CL (mm )  IH  121  111 15  Hi  1.9 (2) 2.7 (4) 1.1 (10) .4 (2) 2.9 (5) 1.2 (2) •0 (2)  LIL  (1) (1)  111  155.  Appendix G.  M o r t a l i t y f a c t o r s a f f e c t i n g peccary populations.  Although a l a r g e number of f a c t o r s are p o t e n t i a l l y capable of causing m o r t a l i t y of i n d i v i d u a l s , level.  few are important at the papulation  I had the opportunity to examine several f a c t o r s which were e i t h e r  thought to be important to peccary populations, or which were p o t e n t i a l l y capable of a f f e c t i n g the populations. These f a c t o r s were predation, paras i t e s and disease and the combination of cold weather and poor n u t r i t i o n . 1.  Predation Despite suggestions by many authors (Knipe, 1958; Jennings 5  H a r r i s , 1953; Neal, 1959b; Murie, 1951] I have found l i t t l e evidence to i m p l i c a t e predators as an important c o n t r o l l i n g mechanism f o r peccary populations i n Texas.  In 1966, I examined stomach contents o f coyotes and  bobcats k i l l e d by the U.S. Fish and W i l d l i f e Service predatory animal trapper on the Santa Gertrudis D i v i s i o n of the King Ranch between June and September, 1966. The major portion of the contents were i d e n t i f i e d by examining the bones, h a i r or feathers i n the f i e l d , and m a t e r i a l which could not be r e a d i l y i d e n t i f i e d was taken back to the l a b o r a t o r y and compared with i d e n t i f i e d specimens. Cotton r a t s were the most common food item and were found i n the stomachs of 56% o f the coyotes, 47% of the bobcats and of the only gray fox (Table 1).  Wood r a t s , c o t t o n t a i l s , and Bobwhite q u a i l were  present i n the stomachs of a small proportion o f the predators.  Only one  coyote stomach contained parts of a w h i t e t a i l deer fawn, and only one bobcat stomach contained the fresh remains of a baby peccary.  Many coyote  scats were examined throughout the study and only one of them had young peccary h a i r present. Table 1. Stomach contents of canid and f e l i d predators trapped on the Santa Gertrudis Div., King Ranch. Species Bobcat Coyote Gray Fox Total  No. Empty 34 10 (29%) 41 15 (37%) 1 76 25 (33%)  Cotton Rat 16 (47%J 23 (56%) 1 (100%) 40 (53%)  Wood CottonRat - t a i l 4 (12%J 4 (12%J 2 (5%) 0  Quail 1 (3%J 2 (5%)  deer 0 1 (2%)  Peccary 1 (3%) 0  6 (8%)  3 (4%)  1 (2%)  1 (1%)  4 (5%)  156. The predators i n the area made extensive use of rodents as a food source (Table 1) during the period when baby peccaries were abundant i n 1966  (text F i g . 22).  The cotton r a t population was very high (120/Acre) at  the time f o l l o w i n g a favorable winter and good r a i n f a l l i n the spring  (v.W.  Lehmann, pers. comm.), and probably acted as a b u f f e r f o r b i r d s and large mammals during the period when the young might be vulnerable to predation. This s i t u a t i o n would adequately explain the low frequency of baby peccary remains i n stomachs of predatory mammals during the period of c o l l e c t i o n . Knowlton (1964), working on the Welder Refuge, found that coyotes were opportunists and made use of the food which was most abundant at the time.  He found l i t t l e evidence to i n d i c a t e that coyotes preyed upon  peccaries at the Refuge, probably because of the high deer population (White, 1966), the several species of rodents that f l u c t u a t e i n density i n a sequential manner on the Refuge (G.R. Raun, pers. comm.; Powell, 1967), and the good crops of mesquite beans and p r i c k l y pear tunas. Of 44 peccaries found dead i n the f i e l d i n south Texas, the cause of death of only 22 could be determined with reasonable c e r t a i n t y and only one of these, a p i g l e t 1 to 2 weeks o l d , was d e f i n i t e l y a t t r i b u t e d to predation (Table 2 ) .  Two other peccaries were found r e c e n t l y dead on  the Welder Refuge and two on the King Ranch with the l a t e r a l abdominal area slashed open and various organs protruding, but otherwise untouched. These slashes were not u n l i k e those;present on the haunches, shouldersand cheeks of some l i v e - t r a p p e d peccaries and were probably i n f l i c t e d by the l a r g e canines of other peccaries. Table 2. Year 1964-5 1966 1967 Total Note:  Cause of death of peccaries found dead i n south Texas. Number 26 5 14 45  Predator 1  1  D.O.R.  3  2 2  2  Winter Mort. 2 1 7  4  10  Fight 2  UnShot Trap known 17 4 3 1 4 4  .1  24  a - Dead on road  My evidence i n d i c a t e s that predators do not prey upon baby pecc a r i e s when rodent populations are high.  Lack of evidence throughout  157.  the remainder of the study i n both west Texas, where predators are scarce, and south Texas, where predators are abundant, suggests that predation i s of l i t t l e importance i n peccary population dynamics.  2.  P a r a s i t e s and diseases Although parasites and diseases seldom have been implicated as  f a c t o r s c o n t r o l l i n g natural populations, the p o t e n t i a l nevertheless e x i s t s (MacLulich, 1937; Bandy, 1968).  During the l a s t h a l f of the study (June,  1966 to August, 1967), we conducted a survey of endo-and ecto-parasites of the peccary mainly i n south Texas, but also i n west Texas. of t h i s study have been published (Samuel and Low, 1970).  The r e s u l t s  In t h i s study,  we found nine endoparasitic species and s i x species of t i c k s , f l e a s and l i c e on peccaries c o l l e c t e d mainly i n south Texas (Table 3 ) , Blood serum samples were c o l l e c t e d from peccaries throughout the study i n south Texas.  The samples were frozen and shipped to the University  of Wisconsin where metabolic i n h i b i t i o n t e s t s (Cook, et a l . , 1965) were run f o r v i r u s antibodies of Eastern equine e n c e p h a l i t i e (EVE), western equine e n c e p h a l i t i s (WVE), C a l i f o r n i a equine e n c e p h a l i t i s (CVE), St. Louis equine e n c e p h a l i t i s (SLVE), Venezuelan equine e n c e p h a l i t i s (WE) and  New  Jersey and Indiana s t r a i n s of v e s i c u l a r s t o m a t i t i s v i r u s (VSN and VSI). Of the 49 serums examined to date 14% reacted to EVE, 6% to WVE, SLVE and 4% to VSI.  No reactors to CVE, WE or VSI were found.  4% to A l l of  these animals appeared i n good health, so i t must be assumed that while the viruses were a c t i v e on the King Ranch, they were not f a t a l . In only one case was there any evidence of i l l n e s s i n the peccaries that were c o l l e c t e d .  This was an 8—year o l d sow that had 8,717  of  the nematode, P a r o s t e r t a g i a heterospiculum i n the lumen of the small i n testine.  She had swollen a x i l l a r y and abdominal lymph nodes and a kidney  f a t index of 0.  The high helminth load may have been the cause of i l l n e s s ,  but there i s no evidence of d i r e c t cause and e f f e c t . I t must be concluded that m o r t a l i t y of peccaries caused by paras i t e s and diseases i s not important to the .population i n e i t h e r south Texas or west Texas. 3.  N u t r i t i o n and cold weather. In south Texas, i t i s u n l i k e l y that food r e s t r i c t i o n s alone  ever cause m o r t a l i t y of adult peccaries. However, when combined with  158.  Table 3.  Prevalence and abundance of p a r a s i t e s of the c o l l a r e d peccary i n Texas (from Samuel and Low, 1970) South Texas Prevalence Abundance , 4% ( 2 5 ) — 3  Species Protozoa Balantidium sp  West Texas Prevalence Abundance , 0% ( 4 )  Nematoda D i r o f i l i a r i a a c u t i u s c u l a 27% ( 4 8 ) 2(1-5) 0% ( 7 ) Gongylonema b a y l i s i " 4% ( 46) 1 0% ( 4 ) ^ Parabronema pecariae 36% ( 53) 5(1-28) 0% ( 4 ) P a r o s t e r t a g i a hetero, spiculum 91% ( 58) 476(7-8717)0% ( 4 ) Physocephalus sp. 86% ( 56) 55(1-370)0% ( 4) Texicospirura t u r k i 48% ( 58) 7(1-48) 0% ( 4) C  C  Cestoda Moniezia benedini  9% ( 58)  1(1-3)  t r%  ( 4)  Trematoda F a s c i o l o i d e s magna  1% (144)  2(2-3)  CP/o  (21)  Ixodidae Dermacentor v a r i a b i l i s Amblyomma cajennense Amblyomma inornatum Haemaphysalis l e p o r i s palustris^ Siphonaptera Pulex porcinus Amoplura Pecaroecus  javalii  '  b  — —  78% ( 42) 3(1-5)(3) 0%(22) 98% ( 42) 116(62-167) 0%(22) (3) 0%(22) 5% ( 42) 1 ( 0 ( 3 ) 7% ( 42) 100% (313)  0% (313)  2(2)(3)  0%(22)  85(35-192)77%(22) (4)  38(0-50] (3)  e  88%(l7)  d  12(5-29) (6)  average number per i n f e c t e d host (range) (number examined i f d i f f e r e n t than in;.prevalence column; only t o t a l c o l lections included). b - Based on examination of feces only. c - Not p r e v i o u s l y reported from the c o l l a r e d peccary i n North America. d - An a d d i t i o n a l 52 animals fromithe Black Gap Area were negative f o r adult P. j a v a l i i , although egg cases were found on four of 14 peccaries c l o s e l y examined f o r egg cases. e - Includes f i v e peccaries from the Black Gap Area which were negative of f l e a s ; a l l 17 peccaries from the Watson Ranch were p o s i t i v e .  159.  other s t r e s s f a c t o r s , n u t r i t i o n appears to be important to s u r v i v a l .  During  the winter of 1966-67, the temperature remained very cold f o r well over a month i n south Texas (text F i g . 2, a & b).  Concurrently, south Texas  was i n a severe drought (text F i g s . 3 and 5) and p r i c k l y pear was the main food source (text F i g . 6 ) .  Two herds were under close s u r v e i l l a n c e during  t h i s period; one on the Welder Refuge had 27 members and the other i n the north end of Mesquite Pasture on the King Ranch had 18 members. herd decreased by 26%  The Welder  between l a t e December and l a t e January with the  death of seven peccaries ranging i n age from 7 months to 13 years.  The car-  casses of four of these animals were found a l l i n t a c t and some f r e s h , and a l l had boluses of p r i c k l y pear f i b e r s taking up over h a l f of the volume of the stomach.  In the three fresh specimens, body and i n t e s t i n a l f a t  were almost l a c k i n g .  In a d d i t i o n coat c o l o r of many of the peccaries,  both l i v e and dead, had turned to the pale, reddish c o l o r a t i o n associated with poor c o n d i t i o n . On the King Ranch, the Caldwell M i l l , herd decreased 33% with the presumed death of three adults and three 9—month o l d j u v e n i l e s during the same period. During the previous year, the temperature had also been cold, but range conditions were good.  The herds d i d not noticeably decrease during  the winter and few winter m o r t a l i t i e s were foun d (Table 2 ) . I t appears that cold weather, during periods when a v a i l a b l e foods are of low q u a l i t y , causes high m o r t a l i t y r a t e s i n south Texas pecc a r i e s because of the excess energy drain through heat l o s s .  This evidence  i s substantiated by reports of very high m o r t a l i t y of peccaries during severe winters i n northern Mexico (Leopold, 1959), Arizona (Knipe, 1958), and Texas (Jennings and H a r r i s , 1953).  I have no estimate of winter mor-  t a l i t y on the west Texas s i t e s , but I presume i t would be s i m i l a r to the south Texas l o s s . 4.  Hunting Hunters k i l l n e g l i g i b l e numbers of peccaries on the King Ranch,  and few on adjacent areas.  I t i s impossible to assess outlaw hunting  on the ranch, but i t occurs mainly i n the perimeter areas.  My c o l l e c t i n g  program removed about 3% of the population' per year i f an average density of one peccary per 100 acres i s assumed over the 200,000 acre d i v i s i o n . Hunting i s not a f a c t o r a f f e c t i n g peccaries i n the immediate area of the  160.  Welder Refuge.  However, several of the l o c a l i z e d herds i n the area of  r e s t r i c t e d habitat around Sinton have been k i l l e d o f f by hunters. Hunting on the Watson Ranch i s r e s t r i c t e d and few peccaries are k i l l e d there.  On the Black Gap W i l d l i f e Management Area, the hunters  probably take 10 to 20°/) of the population. on the herd i s not readily determined.  The effect of t h i s removal  The papulation structure i n bath  west Texas areas i s skewed toward young animals, but hunting can not be the p r i n c i p a l cause since hunting i s not important to the Watson Ranch population. Leopold (1959) found that overhunting can seriously  reduce  peccary populations, but they had a remarkable capacity to persist on suitable  range.  161 .  7. LITERATURE CITED. Andrewartha, H.G. and L.C. B i r c h . 1954. animals. Univ. Chicago P r e s s .  The d i s t r i b u t i o n and abundance  A s d e l l , S.A. 1964. 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