Baboons are African and Arabian Old World monkeys belonging to the genus Papio. The five species are some of the largest non-hominoid members of the primate order; only the mandrill and the drill are larger. The oldest known baboon skull was recently found and it is estimated to be about 2 million year old. Baboons are some of the world's largest monkeys. There are five species of baboon—olive, yellow, chacma, Guinea, and hamadryas—scattered across various habitats in Africa and Arabia. The baboon, like other Old World monkeys, does not have a prehensile (gripping) tail, but it is still able to climb when necessary.