CHANGES IN THE ACTIVITY BUDGET OF CYCLING FEMALE CHIMPANZEES

This study is a preliminary report on the time allocated to various ac tivities by female wild chimpanzees (Pan troglodytes schweinfurthii) d uring their sexual cycle. Cycling females with maximal tumescence (est rous females) tended to spend more time moving than cycling females wi th quiescent sexual skin (anestrous females). Although there was no st atistically significant decrease in any specific activity that corresp onded to the increase in time spent moving, feeding time did decrease in four of the five females. The frequency of approach by females towa rd males and the frequency of approach by males toward females signifi cantly increased when females were in estrus. Direct aggression by mal es occurred more frequently toward estrous females than toward anestro us females. The copulation frequency and the frequency of approach to males was not significantly correlated with the increase in time spent moving. There was a high but not significant correlation between the time spent moving and the frequency of direct aggression by males towa rd females. Mating effort, feeding competition, male aggression, and o ther possible reasons that might explain the increase in moving time a re discussed. (C) 1998 Wiley-Liss, Inc.