Some articles in science journals leave one wondering, that’s for sure. At Nature:
Lethal aggression in Pan is better explained by adaptive strategies than human impacts
Abstract: Observations of chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) provide valuable comparative data for understanding the significance of conspecific killing. Two kinds of hypothesis have been proposed. Lethal violence is sometimes concluded to be the result of adaptive strategies, such that killers ultimately gain fitness benefits by increasing their access to resources such as food or mates1,2,3,4,5. Alternatively, it could be a non-adaptive result of human impacts, such as habitat change or food provisioning6,7,8,9. To discriminate between these hypotheses we compiled information from 18 chimpanzee communities and 4 bonobo communities studied over five decades. Our data include 152 killings (n = 58 observed, 41 inferred, and 53 suspected killings) by chimpanzees in 15 communities and one suspected killing by bonobos. We found that males were the most frequent attackers (92% of participants) and victims (73%); most killings (66%) involved intercommunity attacks; and attackers greatly outnumbered their victims (median 8:1 ratio). Variation in killing rates was unrelated to measures of human impacts. Our results are compatible with previously proposed adaptive explanations for killing by chimpanzees, whereas the human impact hypothesis is not supported. (paywall) More.
Why would anyone think it was humans’ fault that chimpanzees kill each other—or that bears do? Does anyone really believe that these types of life forms would tumble to the idea of living in peace simply because they’d never encountered humans? Wow.
How do we know that lethal aggression is even an adaptive “strategy”? Perhaps an aggressive animal will aggress whether it works for him or not. Under favorable conditions, he survives and breeds but that doesn’t make his tendencies a strategy.
😉 Under unfavorable conditions, the winner might be the animal that quietly left the scene with a nearby female …
See also: Intelligence tests unfair to apes?
Are apes entering the Stone Age?