Does a temperate ungulate that breeds in summer exhibit rut-induced hypophagia? Analysis of time budgets of male takin (Budorcas taxicolor) in Sichuan, China

Abstract

Mammals maximize fitness by optimizing time and energy allocation between reproduction and survival. Describing time budgets is a way to understand a species' constraints in energy allocation. We describe a time budget for male takin (Budorcas taxicolor) in Tangjiahe Nature Reserve, China, to better understand rut-induced hypophagia, which is frequently observed in temperate ungulates that breed in autumn or in winter. Observations generally occurred at two elevations (1200-1600m and 2600-3200m), using 20-min focal animal scan sampling from 2007 to 2009. Feeding behaviors accounted for the majority in takin's time budget (61.1%) during daylight hours, relative to the other observed behaviors, such as rest (14.1%), alert behavior (10.2%) and locomotion (6.8%). We found a negative correlation between feeding behavior and rutting behavior during the rutting season. A ratio of feeding time to resting time increased from pre-rut to rut, while resting behavior did not change significantly across seasons. These results suggest the "energy saving" hypothesis could explain reduced foraging in male takin during the rut, but aspects of the species biology suggest that hypotheses for rut-induced hypophagia developed for other temperate ungulates do not apply to takin. We suggest that the unusual summer rutting season of takin releases males from the energy constraints encountered by temperate ungulates that breed in the autumn and has other benefits for offspring survival. Further research should be conducted on ungulates that exhibit rut during the summer and tropical ungulates that might not experience limited food availability following the mating season to improve our understanding on rut-induced hypophagia.