Chimpanzees killing gorillas: Research shocks scientists as they witness it for first time

Two fatal contacts between wild chimps and gorillas have been documented in the new research. It's a rare instance of one great ape species attacking another, and experts are concerned that climate change may be to blame. Chimpanzees and gorillas can be aggressive and territorial, but their fights—which can be fatal at times—take place nearly entirely inside their own species. Lethal conflicts between two separate great ape species (at least those that do not include humans) are almost unheard of. As a result, new research has been published in Scientific Reports, in which scientists provide insights on two fatal chimp-gorilla confrontations at Loango National Park in Gabon, which is critical.

Violent encounters possibly linked to food scarcity

The cause of these ostensibly random attacks is unknown, however, the fatal encounters could be linked to lack of food availability. Increased food competition in Loango National Park and probably elsewhere, according to the scientists, could result in climate change, though more research is needed to be sure. If this proves out to be the case, it'll be just more evidence of human-caused climate change turning the natural world upside down.

For several years, scientists with the Loango Chimpanzee Project have been studying great apes at the park, learning a lot about their social relationships, group dynamics, hunting behaviour, and communicative ability. From 2014 to 2018, the researchers saw nine instances of chimps and gorillas hanging out together, which is common in this park and elsewhere in eastern and central Africa. These meetings "were always peaceful, and occasionally involved co-feeding in fruiting trees," the authors write in their paper. And, as cognitive scientist Simone Pika of Osnabrück University points out in a press statement, the team's Congolese colleagues have even witnessed it.

Imagine their amazement when the team witnessed not one, but two violent interactions in 2019, both of which resulted in fatalities. In all situations, chimps formed alliances, assaulted gorillas, and took advantage of their superior numbers. Both attacks occurred on the chimps' territory's outskirts, and the major aggressors were adult male chimps. The attacks were visible from around 100 feet away, and the researchers explain them in detail in their latest article.

“Our observations provide the first evidence that the presence of chimpanzees can have a lethal impact on gorillas,” Tobias Deschner, a primatologist at the Max Planck Institute for Evolutionary Anthropology and a co-author of the study, explained in a release from the institute. “We now want to investigate the factors triggering these surprisingly aggressive interactions,” stated Deschner, who co-directs the Loango Chimpanzee Project with Pika.

(With inputs from study: Southern, L.M., Deschner, T. & Pika, S. Lethal coalitionary attacks of chimpanzees (Pan troglodytes troglodytes) on gorillas (Gorilla gorilla gorilla) in the wild)