Sex Differences in Feeding, Height, and Space Use in Hapalemur griseus

Abstract

I investigated sex differences in feeding ecology in a wild group of Hapalemur griseus, gray bamboo lemur, in southeastern Madagascar. Males and females differed in daily dietary diversity, height use while feeding, and spatial position within the group. Based on all-occurrences of feeding bouts and 15-min point samples, the adult female had significantly higher daily dietary diversity indices than those of males. The female also fed at significantly lower heights than the males did. There are also significant differences between age classes with the subadult male exhibiting the lowest dietary diversity and feeding at the greatest heights. During feeding, the female stayed in closest proximity to both juveniles, whereas adult males were peripheral. In contrast, the males moved closer in proximity to the female when resting and traveling. These sex differences could be explained 1) by the metabolic cost of reproduction for females, 2) as strategies to mitigate the cost of feeding competition between males and females, 3) by male role performance as a predator detector, and 4) by different social priorities of males and females.