Primate Diversity

Description

My research focuses on species at very different ends of the
spectrum of primate diversity: small, nocturnal prosimians (mainly
galagos and Lepilemur) and our closest living relatives, chimpanzees
(the latter in collaboration with the Primate Foundation of Arizona
(PFA). My research focuses on topical issues that need to be
investigated in such divergent primates.

First, I am interested in sources of individual variation in social
behavior, most particularly mother-infant interactions, sex
differences, and temperament. Most recently, analyses of data on
captive chimpanzees and galagos suggest that there are minimal sex
differences in the interaction patterns of mothers with infants of each
sex. These data thus suggest that, in behavioral terms, the “costs” of
rearing each sex may not differ dramatically. However, in each species,
interactions of infants with animals other than the mother showed
trends toward differences that seem to fit with patterns of which sex
disperses away from the mother’s range.

In the near future, I plan to examine both data sets for consistency of
individual differences through time, which is one indicator of
differences in temperament between individuals. Second, this work is
done on captive animals, I have focused on studies designed to
critically examine and improve captive housing. A recent study on
galagos found that a number of changes in cage “furnishings” that, from
the human perspective, were thought to improve the cages did not
greatly alter the animal’s behavior. Thus further research in that area
is needed.

My work on nocturnal prosimians also is designed around the question of
“why be social”, as complex sociality is the hallmark of most primates,
most particularly humans. Until recently, most workers have assumed
that the “nongregarious” nocturnal primates were all the same in social
behavior. In a recent review of literature on these species, I
documented the growing knowledge of the diversity of patterns of social
relationships across these species and indicated evidence that kinship
will shape this diversity in ways that are similar to the effect of
kinship on social behavior in monkeys and apes.

I have also shown how energetic constraints in a small, folivorous,
nocturnal Malagasy lemur (Lepilemur) limit its ability to engage in
sociality during the colder (energetically more costly) season of the
year. A paper in press also suggests that energetic constraints may
limit this species’ ability to alter activity budgets in response to
changes in predation risk associated with different moonlight
conditions. In contrast, other nonfolivorous nocturnal primates do
alter their behavior with moonlight conditions. My work thus
contributes to debates about how both diet and predation risk may
influence the evolution of social living.

Other

One of my graduate students, Ph.D. candidate Melissa Schaefer is
working on data on galago growth collected over the 20 year existence
of the ASU Anthropology Galago Colony. Another Ph.D. candidate, Laura
Bidner, is working on her own project on predator-prey interactions of
baboons in South Africa. M.A. students have worked in conjunction with
PFA chimpanzees (e.g Stephanie Meredith on sex differences) or own
their own field projects (e.g. Teague O’Mara in Costa Rica on spider
monkeys.