Social mechanisms of population regulation in a captive group of bonnet macaques (Macaca radiata)

Abstract

The purpose of the present paper is to evaluate the factors that contributed to annual variation in fertility and infant survival in a relatively undisturbed captive group of bonnet macaques (Macaca radiata) over a 16-year period. The size and composition of this population fluctuated over time, and these changes were consistently associated with changes in female fertility and infant survival. Female fertility was highest when there were relatively few adult females in the group and when there were relatively few adult females per adult male. Similarly, infant survival was highest in years when there were relatively few adult females present and when cohorts of infants were small. Since environmental factors, such as availability of food and vulnerability to predation, were unlikely to constrain population growth in captivity, the data suggest that other mechanisms may have affected demographic processes in this captive group.