First lethal attacks by chimpanzees on gorillas observed

Never have I been more disappointed that an article didn’t include video.

> "Whether this behavior is due to competition for food or to the decline of the rainforest's productivity caused by climate change will now be investigated in more detail."

Declaring the cause must be food competition or climate change seems a bit hasty?

These are complex social animals. Given this is the only attack ever observed, it seems possible to me that there are a myriad of plausible one-off explanations. Perhaps a particular chimp or gorilla was having a really bad day and just went out looking for a fight.

They've turned climate change into the new boogeyman, which is a shame since it's an important issue.

Indeed. Chimps will eat gorilla infants. So if the attack was over a scarcity of food resources you'd expect the killed infant to be eaten. This was only observed in 1/2 the encounters...

> Between 2014 and 2018, we observed nine direct interactions between individuals of the Rekambo community and unhabituated gorillas (N=9; see Fig. 1). These events were always peaceful, and occasionally involved co-feeding in fruiting trees (N=2). In 2019 however, we observed two encounters resulting, in both cases, in coalitionary lethal attacks. The first encounter involved a party of 27 chimpanzees and a group of five gorillas. The second involved a party of 27 chimpanzees and a group of seven gorillas (see Table 1, and video clips 1 and 2 in the SA). The first event occurred after a territorial patrol during which the males made a deep incur- sion into a neighbouring chimpanzee territory. The second event happened at the start of a suspected territorial boundary patrol. Both events took place on the outer boundaries of the Rekambo territory (see Fig. 1). The main aggressors in both events were adult male chimpanzees (for details of involvement see Table 1). The two encounters lasted 52 and 79 min, respectively, involved both contact and non-contact aggressions and coalitionary displays from chimpanzees towards gorillas. The gorillas counter attacked and defended themselves using contact aggressions, displays and threat gestures. During the first encounter the silverback was present for 14 min, whilst in the second encounter the silverback was present for 10 min. The first encounter resulted in one dead gorilla infant and three injured chimpanzees; the second resulted in one dead gorilla infant. While there was no indication of consumption of the dead gorilla infant in the first encounter, the infant in the second encounter was almost entirely consumed by one adult chimpanzee female.

https://www.nature.com/articles/s41598-021-93829-x.pdf