Traditional Classification of Anthropoid primates

    Traditional classification is based on recognition of groups of similar organisms, as indicated by the brackets at right. The Anthropoid ("man-like") Apes are distinguished from Old World Monkeys by the absence of a tail. The traditional taxonomy is influenced by the perception that humans are very distinct from the Great Apes (chimps, gorillas, & orangutans) (collectively the family Pongidae), and are therefore a separate group (family Hominidae). Among the apes, tailless gibbons and siamangs are perceived as "lesser apes" that are "monkey-like," and are therefore placed in a separate subfamily Hylobatinae, or even a separate family, Hylobatidae.

    By "promoting" humans to a distinct family, this arrangement incorrectly implies that chimps are more closely related to gorillas than to humans, or that lesser and greater apes are more closely related to each other than the latter is to humans.