Maternal time budgets of gelada baboons

Abstract

Data from gelada baboons, Theropithecus gelada, were used to evaluate Altmann's (1980) model of maternal time budgets. The results provide substantial confirmation of the model's general principles: the time that a female devoted to feeding increased with the age of her infant roughly in line with the model's predictions. However, the rate of increase in feeding time was influenced both by environmental ractors affecting the nutritional quality of the herbage and by the infant's own feeding activities. The results suggest that Altmann's assumption that the additional demand for feeding time is taken out of social time is only partially correct: in fact, social time was conserved as far as possible, with extra feeding time being taken out of resting time initially. Only when the demand for feeding time was so high that much of the available resting time was used up would the female release some of her social time. Evidence is presented to show that when females do give up social time, they seek to preserve those social relationships that are most important to their long-term reproductive interests.