Human apes: The Third Chimpanzee

The Third Chimpanzee: The Evolution and Future of the Human Animal is a 1991 book by academic and popular science author Jared Diamond.

"The title of the book refers to how similar taxonomically chimps and humans are, as their genes differ by just 1.6%, whereas chimps and gorillas differ by 2.3% (p. 19). Thus the chimp's closest relatives are not the other apes with which it is classed, but the human (see Homininae). In fact, the chimpanzee-human difference is smaller than some within-species distances: e.g. even closely related birds such as the red-eyed and white-eyed vireos differ by 2.9%. Going by genetic differences, humans should be treated as a third species of chimpanzee (after the common chimpanzee and the bonobo)."