A monkey is any cercopithecoid or platyrrhine primate. All primates that are not prosimians or apes are monkeys. The 264 known extant monkey species represent two of the three groupings of simian primates. Monkeys are generally considered to be intelligent and, unlike apes, monkeys usually have tails. Elephants are large land mammals in two genera of the family Elephantidae: Elephas and Loxodonta. Three species of elephant are living today: the African bush elephant, the African forest elephant and the Asian elephant . All other species and genera of Elephantidae are extinct, some since the last ice age: dwarf forms of mammoths may have survived as late as 2,000 BC.