[init]

I came here to say that! The bonobo is an an indigenous ape of the left bank of the Congo river in the Congo rain forest in the DR Congo. They look indistinguishable to chimpanzees to the untrained eye.

Gorillas are a whole different species and you have at least 4 subspecies of gorillas, none of which look like chimps or bonobos.

[jimnotgym]

They have some behavioral features that tell them apart from a chimpanzee. Apparently they use sex as a greeting. It is (sort of) anthropomorphized in a hilarious way in the Will Self novel 'Great Apes'. However that may be colouring my memory of how common this is in the real creatures...