| Description |
The seasonal emergence, reproduction, diet, fat deposition and disappearance of six wild populations of the western jumping mouse, Zapus princeps, were studied by trap-recapture methods in the field at elevations of 1860-2900 in the Wasatch National Forest, Salt Lake County, Utah, as well as in the laboratory, from April, 1974 to November, 1976. Emergence timing varied widely between sites, an at a given site in different years. This variation was not related to Increasing elevation, but to the quality of the individual sites. Vegetation development was an excellent predictor of emergence timing at all sites. Emergence of males and females was synchronous except above 2200 in where males preceded females by three to mine days. The gestation period is 18 days. Parturition occurs 19-31 days after female emergence, with lactation continuing up to 35 days after birth of young. Total fat extraction of field-caught animals showed that 68% adult dry weight was fat immediately prior to hibernation. The relationship between fat deposition and juvenile vs. adult mortality is disucssed, and adult longevity is estimated. Analysis of diets of field animals shows that fat deposition is related to increased consumption of seeds, which occurs when seeds becoe available in the habitat. Weight increased prior to hibernation at an average rate of 0.65 g/day, with a maximum of 2.1 g/day. Animals hibernating in the labortory and in the field lost weight at an average rate of 0.07. |
