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Dorothy L. Cheney, Ph.D.

Professor, Dept of Biology
303 Leidy Laboratories
(215) 898-6915, Fax (215) 898-8780
email:   cheney@psych.upenn.edu
For more information, http://www.psych.upenn.edu/~seyfarth/Baboon%20research/index.htm
Click here for selected publications since Dr. Cheney's arrival at Penn

RESEARCH INTERESTS

RESEARCH TECHNIQUES

RESEARCH SUMMARY

My research is conducted jointly with Prof. Robert M. Seyfarth (Psychology). Our current research subjects are drawn from two groups of free-ranging baboons (Papio cynocephalus ursinus), which we study in the Moremi Game Reserve, Okavanago Delta, Botswana.

Part of our research examines the predator alarm calls given by baboons to lions, leopards, crocodiles, and pythons. Theory suggests that acoustically different alarm calls should evolve whenever animals confront different predator species whose hunting strategies require different modes of escape. For example, East African vervet monkeys confront a variety of different predators (leopards, eagles, and snakes) that hunt in different ways and require different escape strategies. Presumably as a result, vervets possess a number of acoustically distinct alarm calls, each of which elicits a different, adaptive response.

Baboons in our study area respond differently to different predators. For example, when they encounter lions at close range they escape into trees but when they encounter leopards, at least during daylight hours, they chase and even attack them. When baboons encounter pythons they become vigilant, approach, and give alarms, but when they encounter crocodiles near the river they give choruses of alarm calls and flee from the water's edge.

Despite these different responses, however, the alarm calls that baboons give to different predators grade acoustically into one another. This observation is significant because it argues against the hypothesis that selection favors the evolution of acoustically distinct calls whenever individuals confront predators with different hunting strategies or social events like inter-group encounters that demand qualitatively different responses. We are currently conducting playback experiments to test the hypothesis that baboons respond to a graded series of alarm calls with qualitatively different responses.

A second part of our research examines what primates know about the social relations that exist among others in their group. To survive and reproduce, a monkey must be able to predict the behavior of others. In nonhuman primate groups, where alliances are common, competition demands that a monkey learn and remember all of its opponents' dyadic and triadic relations. The complexity of primate social life, therefore, predicts that monkeys have a sophisticated knowledge of the relations that exist among their companions. We are currently conducting playback experiments to test hypotheses about the structure of social knowledge in the minds of free-ranging baboons.

In addition to our own work, Prof. Cheney and I direct the field research of graduate students and post-doctoral fellows who are currently studying social behavior and vocal communication among spider monkeys (Ateles geoffroyi) in Mexico, mangabeys (Cercocebus albigena) in Ivory Coast, capuchin monkeys (Cebus capuchinus) in Costa Rica, and suricates (Suricatta suricatta) in South Africa.

KEY WORDS: