Anatomical differences between Common and Pygmy Chimpanzees are slight, but in sexual and social behaviour there are marked differences. Common Chimpanzees have an omnivorous diet, a troop hunting culture based on beta males led by a relatively weak alpha, and highly complex social relationships; Bonobos, on the other hand, have a mostly vegetarian diet and an egalitarian, matriarchal, sexually promiscuous culture.
The genus Pan is nowadays considered to be part of the subfamily Homininae to which humans also belong, although humans were once segregated from the other great apes in different families. Biologists believe that the chimpanzees are the closest evolutionary relatives to human beings. Their common ancestor branched off from its latest common ancestor with us as recently as 4 to 7 million years ago, and they have 98 - 99.4% of their DNA in common with humans, which prompted biologist Jared Diamond to dub our species "the third chimpanzee". Some biologists believe that assigning chimpanzees to a different genus or even family than humans, a taxonomic division which Carolus Linnaeus instituted and later regretted, is an instance of anthropocentrism unjustified on biological grounds. Many modern primatologists now place all of the great apes, including humans, into one family, with all but the Orangutan in the same subfamily.