Activity budget of Rhinopithecus bieti at Tibet: Effects of day length, temperature and food availability

Abstract

Abstract How animals allocate their time to various activities has significant consequences for their survival because they reflect the different constraints on time-energy balances. Many ecological variables, such as day length, temperature, food availability, are supposed to effect on activity budgets allocation of temperate primates. To examine the potential influence of these three variables, the activity budgets of Rhinopithecus bieti was studied at Xiaochangdu, Tibet from June 2003 to March 2005. Pearson correlations were utilized to assess potential relationships between activity budget and day length, food availability and temperature, and stepwise multiple regressions to identify the priority of resting and other activities (activities besides feeding, moving and resting). Time spent resting and doing "other activities" is positively related to day length, temperature and food availability. No significant correlations were found between feeding/moving time and any of these variables. This suggests that foraging time (feeding + moving) takes priority over rest and other activities. Day length and foraging time (as independent variables) were related to the time spent in the other two activities besides feeding/moving (as dependent variables). Both time spent resting and in "other activities" were highly significant positive functions of day length, with the latter a highly significant negative function of feeding time and moving time. Resting time may therefore be interpreted as taking priority over "other activities" time. These results provide further evidence of the importance of day length, temperature and food availability to seasonal activity budgets .