Welcome

The Kibale Chimpanzee Project is a long-term field study of the behavior, ecology, and physiology of wild chimpanzees. Our researchers and field staff conduct daily behavioral observations on a group of ~50 chimpanzees in the Kibale National Park in southwestern Uganda. This research provides key contributions to understanding primate behavioral diversity, tracing the evolution of human biology and behavior, and conserving chimpanzees and their habitat.

The Kasiisi Project: Helping Ugandan Children One School at a Time

Our partner organization, The Kasiisi Project, has launched a beautiful new website! Now is a great time to highlight the important work they do to help Ugandan schoolchildren in the area around Kibale National Park.  Recognizing the wide range of impediments for rural children to succeed in school and make it out of poverty, The Kasiisi Project works on multiple fronts.  Programs start with the fundamentals of providing safe and adequate school buildings, supplying books and materials, training teachers, promoting literacy, and funding scholarships for higher education.  They extend to fostering student nutrition, health, and hygiene both through practical measures and through educational programs to keep kids coming to school.  Children are supported from nursery school through to college (a Kasiisi graduate was just accepted to Harvard University!).  Conservation is an important part of the Kasiisi Project’s objectives.  Students and their families receive training and materials to foster sustainable energy use and alternatives to exploiting the forest.  And, of course, chimpanzee and forest conservation are a focal part of learning (and fun!) throughout the program.

What sparks fights between chimpanzee communities?

Since the 1970s, researchers have known that male chimpanzees defend
group territories, and that fights between groups can be deadly.

But what triggers these fights? Do chimpanzees go looking for trouble? Do they get into fights over mates or over some other resource, such as food? And when they do meet the neighbors, what determines whether they fight or flee? Are they more likely to respond aggressively if they are defending mates, or young infants, or food? Or does strength in numbers matter more?

A study that appears in this month’s issue of the journal Animal Behaviour sought answers to these questions using 15 years of behavioral and ecological data collected on Kanyawara’s chimpanzees.  The study, led by Michael Wilson, found that intergroup encounters occurred most often when key foods attracted chimpanzees into border areas. Once Kanyawara chimpanzees detected their neighbors, though, their response depended mainly on strength in numbers, rather than the presence of food resources or
mates.

Read the full article here.

Cultural bias in chimpanzees

Experimental work by Thibaud Gruber, in Kibale National Park and the Budongo Forest, suggests that wild chimpanzees’ cultural biases influence the tools they use to solve novel tasks.

Gruber investigated whether chimpanzees from Sonso and Kanyawara approached a novel task — extracting liquid honey from a log with an artificially provided leafy stick — in community-specific ways. Kanyawara chimpanzees, who sometimes use sticks for food acquisition, tended to use the stick as a dipping tool to remove the honey. Sonso chimpanzees, who have never been observed using sticks in a foraging context, found the leaves to be the most salient part of the tool. Some produced leaf-sponges, but none used the stick to obtain honey.

In a second experiment, Gruber exposed Sonso chimpanzees to the preferred Kanyawara approach to the task by placing leafy stick tools in the honey, prompting them to retrieve the leafy stick directly from the hole. Although some of the chimpanzees touched or manipulated the stick, none of them used it as a tool to obtain honey.

Further research is needed to understand the learning mechanisms chimpanzees use in the wild, but these results suggest that cultural bias constrains how individuals from different communities perceive and evaluate their environment. They also suggest that in some contexts, social learning may be more important to chimpanzees than individual trial- and-error learning. The article appears here in the journal Scientific Reports.

Kanyawara chimpanzee behavior profiled in National Geographic

Wangari, an adolescent female, carries a stick while traveling and feeding in a fig tree (photo: Alain Houle).

Kanyawara juveniles – especially females – carry sticks in a manner suggestive of a rudimentary form of doll play (see May 8, 2011 post). A photo of chimpanzee “dolls” appears in the Sept 2011 issue of National Geographic magazine. Click here to view the photo.

A Matter of Life and Limb

Max has lost both feet to wire snares. Photo by Ronan Donovan

Due to Ugandan cultural views, which place the eating of apes as taboo, chimpanzees in Kibale National Park are thankfully free of poaching pressure.  However, our chimpanzees face a continuing threat of getting caught in wire snares placed (illegally) by local hunters to trap other wildlife, such as duikers and bushpigs.  Kibale Chimpanzee Project field manager Emily Otali and chimpanzee Max (pictured above) were recently featured in a Science Magazine highlight of the snaring problem.  Read the article here.  You can also read more about the snaring problem and other conservation issues under our Conservation tab.

Teddy’s death and the aftermath

Late on January 20, 2011, Teddy apparently fell to an accidental death. She was a 19-month-old who was last seen alive by researchers about 5 p.m., feeding in a large Ficus natalensis with a big group, apparently completely healthy.  Evidence of her fate came from heavy bruising on her face when Tongo was carrying her next day shortly after dawn. Teddy seemed to have landed face down.

For the next two days Teddy’s mother, Tongo, kept her daughter’s body close, repeatedly gazing at it, grooming it, or waving flies away. Sitting by the corpse or slinging it on her back was little problem, but climbing with a 12-pound lifeless body was hard. Tongo kept her hands free by clenching her infant’s wrist between her head and shoulder while the body dangled down her back. Sometimes she pulled herself up by her arms while nestling the corpse on her thighs. On occasion, seemingly exhausted, Tongo ventured a few yards from Teddy. Someone else in the family then took over. At six years old and still much smaller than an adult, her daughter Tsunami did not have the strength to carry her sister’s body but she dragged it towards her mother, sat with it and groomed it until her mother was ready to carry it once more.

By the third morning the corpse was starting to disintegrate. Tongo left it in her sleeping-nest when she climbed out for her morning meal. Tsunami came to investigate but her climb disturbed the body and it slipped out of the nest and landed on a branch-fork below. Hours later members of our team climbed up and retrieved it. Tongo watched but did not interfere. She screamed and went on her way.

Life is hard in the forest – so hard, indeed, that the capacities of empathy and cooperation that captive experiments show chimpanzees to be capable of must sometimes fall victim to baser urges. On the first morning of Tongo’s loss she was in a group with ten adult males. Her adolescent son Tuber approached and touched the dead Teddy, but none of the adults showed any interest in the corpse, nor any concern for Tongo’s loss. None, for example, approached to groom her, or paid any other kind of friendly attention.

Until Teddy died, Tongo would have been unlikely to mate for another year or more. But with her nursing infant gone she could be expected to come into estrus within days. Perhaps that is why just a few hours after Teddy died, adult male Makoku chased Tongo till she screamed, and why he inspected her genitals a few hours later. She suffered five attacks that first day, from four different males. The screams she gave while clutching her dead baby or running back to collect the corpse were typical of females who are slapped about by males. They seemed to come from fear and resentment, not mourning. During the next few weeks Tongo was accompanied by males most days, and was attacked on average once a day. Every male attacked her except one, her adult son Lanjo.  Then the sexual free-for-all began, less than four weeks after Teddy’s death. Alpha male Kakama had been the most frequent aggressor to Tongo. True to form, once she became sexually ready he had the most copulations. In seven days Tongo mated with every adult male (except Lanjo again) until, after at least 57 copulations, she slipped away from researchers and other chimpanzees to be alone with Bud, one of the younger adult males, and thereby gained a respite from the mayhem.

In captivity chimpanzees will spontaneously give an object to someone reaching for it, and among those that like each other, they can urge each other to pull a rope to reach a food reward that neither could get alone.  So we might reasonably have expected that in the wild, feelings of kindness and generosity might have impelled some in Tongo’s community to help her when she was being picked on. But whereas young Tsunami stepped in to drag her sister’s corpse, no others came to Tongo’s aid. Mutual interests in self-protection provide the most frequent context for support among females, and even then their help is limited. They might cooperate in battling against young immigrant females trying to settle for a lifetime in the same disputed area of forest, but since all females are lower-ranking than any male, they are wary of fighting against males. No female chose to rally behind Tongo when she was victimized by male bullying.

Teddy’s death was sad for Tongo and her family, but at least it had one valuable scientific outcome. The corpse allowed us to describe the intestines of a known-age healthy infant chimpanzee from the wild – the first time anyone has done so.

Richard Wrangham and Emily Otali

Happy 2011 KCP!

At the end of 2010, the Kanyawara community maintained a group size of more than 50 individuals. Despite the fact that they live in disturbed mid-altitude forest on the edge of the national park, where they are vulnerable to human predation and exposed to various sources of human disease, this is the same community size as when the study began, more than 2 decades ago. The Kanyawara experience shows that even in the face of substantial human influence, chimpanzees living in sub-optimal habitat can thrive. We believe that conservation education and the presence of a long-term research station have contibuted to the success of this population. Pictured are members of the KCP research and anti-poaching teams.

Kanyawara Chimpanzees Featured in Ranger Rick

Kanyawara chimpanzees were featured in the May 2010 issue of Ranger Rick magazine. The article teaches children about chimpanzee social life from the perspective of a developing infant. Thanks to photographer Suzi Esterhas for such an excellent job capturing the faces of the Kanyawara chimpanzees.

New Publication: Chimpanzee Play

Sex differences in chimpanzees’ use of sticks as play objects resemble those of children. Sonya M Kahlenberg and Richard W. Wrangham (2010). Current Biology 20: R1067-R1068
Sex differences in children’s toy play are robust and similar across cultures. Evidence for biological factors is controversial but mounting. In this paper, we present the first evidence of sex differences in use of play objects in a wild primate, in chimpanzees. We find that juveniles tend to carry sticks in a manner suggestive of rudimentary doll play and, as in children and captive monkeys, this behavior is more common in females than in males.

• Read coverage of this study in BBC Wildlife Magazine