Ape years ago (Mya) the clades diverged into newer clades. The lesser apes are the gibbon family, Hylobatidae, of sixteen species; all are native to Asia. Their major differentiating characteristic is their long arms, which they use to brachiate through trees. Their wrists are ball and socket joints as an evolutionary adaptation to their arboreal lifestyle. Generally smaller than the African apes, the largest gibbon, the siamang, weighs up to ; in comparison, the smallest "great ape", the bonobo, is . Formerly, all the great apes except humans were classified as the family Pongidae, which conveniently provided for separating the human
The Naked Ape The Naked Ape The Naked Ape: A Zoologist's Study of the Human Animal (Hardback: ; Reprint: ) is a 1967 book by zoologist and ethologist Desmond Morris that looks at humans as a species and compares them to other animals. "The Human Zoo", a follow-up book by Morris that examined the behaviour of people in cities, was published in 1969. "The Naked Ape", which was serialised in the "Daily Mirror" newspaper and has been translated into 23 languages, depicts human behaviour as largely evolved to meet the challenges of prehistoric life as a hunter . The book was so named