UBC Theses and Dissertations
Development of the Columbian black-tailed deer (Odocoileus hemionus columbianus) during the fetal period Ommundsen, Peter D.
A series of 88 fetuses of the Columbian black-tailed deer (Odocoileus hemionus columbianus) was examined and measured. From the data obtained it was possible to reconstruct the probable sequence of changes in morphology and patterns of relative growth that occur during the development of the fetus. A series of stages of development was outlined, based on external morphological characteristics. The auricles of the ears appear to be the fastest-growing structures in relation to body length. The cranial portion of the skull grows in diameter faster than the inter-orbital region. In length, the preorbital and postorbital segments of the skull show similar growth rates. The neck grows in circumference relatively faster than the abdomen. The hind limbs grow faster than the fore limbs. Greater differences in patterns of relative growth were observed between this subspecies and the Northern white-tailed deer (O. virginianus borealis) than between the black-tailed deer and Rocky Mountain mule deer (O. h. hemionus). Some sources of variation were examined, including technical problems, individual differences, differences between the sexes and the relationship between size and form. Not all regions appear to develop at the same rate in different animals Males were found to.be larger than females at the same stage of morphological development. Some body dimensions had a much higher correlation with structural change than did others.
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