Adaptation and Phylogenetic Constraints in the Antipredator Behavior of Ringtailed and Ruffed Lemurs

Abstract

The antipredator responses of forest-livin ringtailed (Lemur cafta) and ruffed (Varecia vm'egafa) lemurs were documente 'f over a three ear period at the Duke University Primate Center (DUPC, Durham, NC, ~ s A ) . Vocal and nonvocal responses to naturally-occumng and simulated predators are described, and their functions are considered with respect to species-specific differences in body size, ecology, and reproductive biology. Nonvocal responses of the two lemur species differed most conspicuously in pro ensity of predator-directed aggression: whereas ringtailed lemurs enerally evade predators, ruffed lemurs were likely to i a confront or attack them. nterspecific variation in vocal responses to predators included differences in call diversity, stimulus specificity, and function. Ringtailed lemur antipredator behavior (includin large group size) is viewed as an adaptation to nontrivial levels of pre dpa tor pressure that stem from being a relatively small-bodied, semi-terrestrial primate living in an o en habitat In contrast, the highly aggressive antipredator behavior of the ruffedfemur is seen in part as an effect of a somewhat larger body size, but also as a constraint of producing sessile offs ring that do not cling to the mother. Thus, in contrast to rinqailed lemurs, ru fPed lemurs with infants cannot flee predators without risking then reproductive success.