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ASU primatology, snare removal program supports chimpanzee conservation

Side-by-side photos of a chimp in a forest.

Chimpanzees caught in snares lose and injure their fingers, toes, hands and feet. Lita (left), an adult female chimpanzee, lost her foot. Photo by Kevin Langergraber. Peterson (right), an adult male, was the only chimpanzee snared at Ngogo after ASU primatologist Kevin Langergraber and his team started the snare removal program in 2011. With the help of the Uganda Wildlife Authority, they successfully removed his wire snare. Photo by Kevin Lee

June 07, 2024

Snares are a common tool often used by hunters in Uganda looking to catch small, wild game meat. Unfortunately, the snares are also capable of catching wild chimpanzees, resulting in injured fingers, toes, hands, feet — and sometimes complete amputation.

Kevin Langergraber, an associate professor at Arizona State University's School of Human Evolution and Social Change, has been studying the Ngogo community of chimpanzees in Kibale National Park in Uganda for over two decades.

Chimpanzee sitting in a tree
Christine, an adult female chimpanzee of the Central Ngogo chimpanzee community. Photo by Kevin Langergraber

A research scientist at the Institute of Human Origins at ASU, Langergraber serves as director of the Ngogo Chimpanzee Project, where he and a team of scientists study, research and work to protect the primates through conservation efforts.

After witnessing and helping chimpanzees who were getting injured in snares, Langergraber and his team decided to implement a snare removal program in 2011. Their report, published last month in the journal Primates, is the first to statistically show how snare removal helps conservation efforts.  

“We compared the number of times chimpanzees were snared during the 12.75 years after the start of this project with the number of times individuals were snared during the previous 14 years," Langergraber said. “Only one chimpanzee was snared after we began removing snares, compared with 12 individuals caught during the period before.”

This showed a 79% reduction in the number of victims after implementing the snare removal program. In their report, “Removing snares is an effective conservation intervention: a case study involving chimpanzees,” the scientists explained that snared chimpanzees have more intestinal parasites, are not able to run fast — putting them in danger of being attacked by other chimpanzees — and have decreased locomotor skills, making it difficult to safely be in the canopy of the forest.

Langergraber helped free a chimpanzee from a snare while he was following the Ngogo chimps outside their normal trail systems. The chimpanzees make journeys outside their normal areas to hunt for monkeys and even other chimpanzees from outside groups, he explained. These farther-out areas are where they are most likely to encounter snares. 

“There was a commotion and screaming at the front of our party that I could not see,” he said. “It turned out that an old female, Tosca, had her hand caught in a metal wire snare at this log.

Chimpanzees in a forest.
Members of the Western Ngogo chimpanzee community resting while on a territorial boundary patrol. An adolescent female, Ellen, stands bipedally to look and listen for neighbors. Photo by Kevin Langergraber

“The rest of the chimps crowded around her, with some reassuring her. But they did not try to help her get out of the snare. After she screamed for a while, I decided to try and free her. Luckily, there was a dense bush to sort of keep us separated. I just had a tiny pocket knife with me, so all that I could do was to try and cut the tree that the wire was attached to, so that although she would still have the wire wrapped around her finger, she at least would not be trapped there. She was freed and the wire eventually fell off, but not without some severe damage to her fingers.”

Since the start of the snare removal program, there are now eight two-person snare removal teams that patrol Kibale National Park in cooperation with the Uganda Wildlife Authority.

Langergraber encourages people who want to learn more about chimpanzees and conservation in Ngogo to watch "Chimp Empire." The four-part Netflix series was launched in 2023 and gives a never-before-seen account of the chimpanzees scientists and Langergraber study

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