Homonoid Evolution

I have an intense dislike of the tendency for many human evolutionary biologists and comparative psychologists to reflexively jump to the conclusion that any whiff of complexity in human behavior or social structure must by uniquely human. It’s wreaks of latent creationism. It violates the central premise of phylogenetics, that it’s more likely that characters shared between species are derived from a common ancestor than independently evolved. The uniqueness claim also regularly turns out to be false once actual evidence is collected. Tool use anyone? And it bolsters the human superiority narrative that provides the justification for much of raping and pillaging that is destroying our planet and pushing endangered species to the brink.

That’s why I encouraged my former student Robin Morrison to use observational data from two forest clearings visited by gorillas in Congo to test the common claim that hierarchical social structure was a uniquely evolved human trait that had all sorts cascading effects for human social evolution. What we found was that gorillas also had hierarchically nested association patterns rising up to something approximating the clan level. This was not surprising, given that effectively the same result had previously been published for both elephants and cetaceans. These field study results just had not seeped into the hermetically sealed human evolution and comparative psychology worlds.

Robin and I also collaborated with Magdalena Bermejo to test the conventional wisdom that ape territoriality first evolved on the most recent common ancestor of chimpanzees and gorillas. Using camera trap data documenting the ranging patterns of multiple gorilla groups at the Ngaga site in northwest Congo, we found evidence that gorillas actually were defending territories, not just guarding mates.