UBC Theses and Dissertations
Natural salt licks as a part of the ecology of the mountain goat Hebert, Daryll Marvin
The role of natural earth licks in the ecology of the mountain goat (Oreamnos americanus (Blainville)) was studied during the summers of 1965 and 1966 in the Rocky Mountain Trench of southern B.C. The patterns of movements of the animals were determined as they used the licks and the vegetation, lick soils and blood serum were analyzed with respect to sodium content. The predicated use of licks as suggested by other workers involves the idea that sodium may be the attracting element. The present study examined seasonal and differential patterns of movement, along with periodicity of use, in order to determine the resultant interplay of animal movement and sodium and water content of the vegetation. The goat encounters such additional risks as predation, parasitism, hunting and joint use while using the lick seasonally. Since the goats use the lick differentially in time, each sex is affected to a different degree by the above factors. Differential use also produces characteristic patterns of grouping and molting. Periodicity of use occurred mainly in the afternoon, although distance travelled and complexity of the lick may affect time of entry, length of stay and group size. The frequency of use differed at each lick, with the average time of use by an individual being one to three weeks. Environmental factors such as temperature and weather appear to regulate the movement to and from the lick. Analysis of the vegetation revealed that sodium was extremely low and that potassium was present in sufficient quantities to meet the requirements of the animal. No significant trends were found to exist from spring to fall or due to changes in elevation, as far as sodium and total ash were concerned. Observations indicated that animals select certain licks over others and select sites within a lick. These high licking sites were shown to have a higher sodium content. Newly established licks had a higher sodium content than did old licks, however, highly preferred sites were not always higher in calcium, phosphorus or cobalt. A normal range of serum sodium values was established for the goat but due to the regulatory function of the kidney, changes in serum sodium due to lick use could not be detected. Serum sodium decreased with age. A female with a kid had a low serum value. It appears that the level of deficiency causing the craving is not sufficient to show up in serum analysis. Animals died during trapping operations and a selenium deficiency was suspected. Gross symptoms approximated those attributed to white muscle disease and the vegetation contained selenium in amounts which are known to cause this myopathy.
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