Monkeying Around

NATALIA WOJCIK

Challenging conventional wisdom, studies at Kibale have dispelled the notion that male chimpanzees give meat to females in exchange for sex, or that female chimpanzees are able to choose their own mates.

Natalia Wocjik, Article Image 2Since the days of Darwin, the idea that humans and chimpanzees share a close common ancestor has been examined on many levels. Today, studies of animal communities are producing anthropological implications. At the Kibale Chimpanzee Project in Uganda, a 776 square-mile nature reserve and research space founded in 1993, Harvard faculty and project team members are teaming up to explore primate diversity and the evolution of contemporary humans.

While biological anthropologists can gain a detailed evolutionary picture just by studying mammals like mice, pigs, or monkeys, Professor Richard Wrangham chose instead to focus on our closer brethren, chimpanzees. With this task in mind, Wrangham established the Kibale Chimpanzee Project in 1987, supported by a host of institutions including Harvard University, the U.S. National Science Foundation, and National Geographic Society.

The initial inspiration for the Kibale project came from the need to study significant variations between populations of chimpanzees, as well as a lack of long-term primate studies, a fact Professor Wrangham realized during his study of chimpanzee behavioral ecology with Jane Goodall in Gombe National Park in Tanzania in the early 1970s. Perhaps the most intriguing question Professor Wrangham posed was whether the patterns of “fear of the neighboring community were characteristic of chimpanzees as a species, or were idiosyncracies of Gombe in particular.”

Through the Kibale project, Professor Wrangham says that researchers have discovered substantial confirmation of “wild chimpanzees both killing and being killed by their neighbors,” with parallel reflections in the way chimpanzees travelled along their borders and in what quantities. In conjunction with several other longterm chimpanzee research facilities, the Kibale Project has begun to study and develop the broader scope of these war-like hostilities and their implications.

Professor Wrangham also stated that the decision to work with chimpanzees rather than bonobos on the Kibale project stems from the fact that bonobos, like humans, became specialized throughout their evolutionary trajectory after diverging less than a million years ago, thus conceding victory to the chimpanzee as “an excellent guide to the cognitive and behavioral abilities exhibited by our pre-hominin ancestors.” Natalia Wocjik, Article Image 1

Throughout the years, the Kibale Project has proven to be a priceless fountain of discovery. Challenging conventional wisdom, studies at Kibale have dispelled the notion that male chimpanzees give meat to females in exchange for sex (Gilby et al 2010), or that female chimpanzees are able to choose their own mates (Muller et al 2011). In addition, Kahlenberg and Wrangham have noticed a pattern of stick carrying, mostly among young females, similar to the role of the doll in human culture. This evidence, together with an experiment carried out with the Kibale chimpanzees and those in nearby Budongo, has presented startling new finds indicating tangible evidence of unique subcultures between different populations of chimpanzees. Further corroboration of this diversity was found when only the Kibale chimpanzees, and not ones from Budongo, were able to extract water of honey from holes, presumably due to the knowledge from the previous generations that stick can be helpful.

When asked about future prospects for the Kibale Project, Professor Wrangham cited a shift in focus to the study of the development of chimpanzees from infancy, with some concentration on the differences among sexes. The professor cited dental photographs as a mechanism to chart “developmental timing and their relationship to changes in diet,” a technique that will allow for a better understanding of integration of behavior and anatomy, illuminating our own evolutionary roots in the process.

This project, with its unique international connections, will continue to provide insight into our lineage through its research on chimpanzee, using innovative new techniques such as the aforementioned to contribute to solving the mystery of our origins and the very process by which we develop diversity and culture. Continued attention will be placed on the close common ancestor that humans and chimpanzees shared, to produce further anthropological findings.

Further Reading
Emery Thompson, M., Muller, M. N., Kahlenberg, S. M. & Wrangham, R. W. 2010. Dynamics of social and energetic stress in wild female chimpanzees. Hormones and Behavior, 58, 440-449.

Emery Thompson, M., Muller, M. N. & Wrangham, R. W. 2012a. Variation in muscle mass in wild chimpanzees: Application of a modified urinary creatinine method. American Journal of Physical Anthropology, 149, 622-627.

Emery Thompson, M., Muller, M. N. & Wrangham, R. W. 2012b. The energetics of lactation and the return to fecundity in wild chimpanzees. Behavioral Ecology, 23, 1234-1241.

Gilby, I. C., Emery Thompson, M., Ruane, J. & Wrangham, R. W. 2010. No evidence of short-term exchange of meat for sex among chimpanzees. Journal of Human Evolution, 59, 44-53.

Gruber, T., Muller, M. N., Reynolds, V., Wrangham, R. & Zuberbühler, K. 2011. Community-specific evaluation of tool affordances in wild chimpanzees. Sci Reports, 1: 128, 1-7.

Kahlenberg, S. M. & Wrangham, R. W. 2010. Sex differences in chimpanzees’ use of sticks as play objects resemble those of children. Current Biology, 20, R1067-1068.

Langergraber, K. E., Prüfer, K., Rowney, C., Boesch, C., Crockford, C., Fawcett, K., Inouef, E., Inoue-Muruyamag, M., Mitanih, J. C., Muller, M. N., Robbins, M. M., Schubert, G., Stoinski, T. S., Viola, B., Watts, D., Wittig, R. M., Wrangham, R. W., Zuberbühler, K., Pääbo, S. & Vigilant, L. 2012. Generation times in wild chimpanzees and gorillas suggest earlier divergence times in great ape and human evolution. Proceedings of the National Academy of Sciences, 109, 15716-15721.

Langergraber, K. E., Schubert, G., Rowney, C., Wrangham, R., Zommers, Z. & Vigilant, L. 2011. Genetic differentiation and the evolution of cooperation in chimpanzees and humans. Proc. R. Soc. B, 278, 2546-2552.

Muller, M. N., Emery Thompson, M., Kahlenberg, S. M. & Wrangham, R. W. 2011. Sexual coercion by male chimpanzees shows that female choice may be more apparent than real. Behavioral Ecology and Sociobiology, 65, 921-933.

Smith, T. M., Machanda, Z., Bernard, A. B., Donovan, R. M., Papakyrkos, A. M., Muller, M. N. & Wrangham, R. 2013. First molar eruption, weaning, and life history in living wild chimpanzees. Proceedings of the National Academy of Sciences, 110, 2787-2791.

Wilson, M. L., Kahlenberg, S. M., Wells, M. & Wrangham, R. W. 2012. Ecological and social factors affect the occurrence and outcomes of intergroup encounters in chimpanzees. Animal Behavior, 83, 277-291. Wrangham, R. W. & Glowacki, L. 2012. War in chimpanzees and nomadic hunter-gatherers: evaluating the chimpanzee model. Human Nature, 23, 5-29.

Natalia Wojcik is a Brevia staff writer. She can be reached at nataliawojcik@college.harvard.edu.
Featured image credit: ScienceBlogs