An ape is any homonoid (member of superfamily Homonoidae). This includes the "lesser apes," 13 species of gibbon, which live in the tropical and subtropical forests of Southeast Asia, and the "great apes," family Homonidae, which includes orangutans, gorillas, chimpanzees, and humans, all of which are closely related. The characteristic features of these animals include large brains and long limbs which are usually adapted for climbing trees. Among these homonoids, only humans and gorillas are poor climbers.
All apes are omnivores, consuming fruit, grass seeds, and occasionally bugs or small animals. Some are vegetarians, like the gorilla, while others engage in hunting, like chimps and humans. Most are social, especially humans, which traditionally live in groups of up to about 200 members, though cities can be arbitrarily large.
Apes evolved out of Old World Monkeys, which have smaller brains and bodies and less social organization. These in turn evolved from arboreal primates that resemble living species such as lemurs. Like their relatives the Old World Monkeys, apes are one of the few groups of animals to have three-color vision, also displayed by marsupials and bees. They largely rely on their astute vision and ability to run away quickly through the trees to avoid predators such as felids and canids. Others, like the gorilla, rely on their size and strength, while humans rely largely on tools.
These animals evolved about 25 million years ago in Africa or Asia, where they remained until humans migrated to Europe and the rest of the world only about 90,000 years ago. Great apes split from the lesser ones about 18 million years ago. Orangutans split from the others about 14 million years ago, gorillas split off about 8 million years ago, and chimps and humans split about 3-5 million years ago. The line that gave rise to humans produced various species, including Homo erectus, which were intelligent enough to use tools and spread across much of modern-day China and India. It is completely unknown whether these early relatives of humans could use complex speech. They may have even been smart enough to build rafts and travel short distances across the ocean.
Most of present-day non-human apes are endangered due to overhunting and the destruction of rainforest habitat. In the entire world, there are about 70,000 orangutans, 300,000 chimpanzees, and 200,000 gorillas. Their numbers have declined greatly in the last century.