Tropical rainforests cover less than 2 per cent of the Earth's surface, but more than half of the animal species in the world make their homes there. Among this extreme biodiversity exist many species of monkey, some still being discovered. These species, besides being many in number, have distinct characteristics that make them each unique.
Found in tropical rainforests from Costa Rica through the southern edges of the Amazon are dozens of tamarin species. Most of these are no larger than the size of a squirrel, and several species are distinctly odd-looking. The brown emperor tamarin, for example, possesses a red tail and a white handlebar moustache. The endangered golden lion tamarin, only about a pound when completely grown, has a full mane of golden hair around its tiny head.
There are nine species of howler monkey, the largest monkeys in the tropical rainforests of the Americas. They can grow to be 3 feet tall with tails just as long, used for grabbing onto branches. These monkeys are the loudest land animals in the world and can be heard up to three miles away. Howler monkeys generally live no longer than 15 years in the wild, and they are hunted for food and sport.
The proboscis monkey lives exclusively in Southeast Asia on the island of Borneo. Its name derives from its prominent nose, which on males hangs in the way of its mouth, turns red with excitement, and sticks straight out when danger is sensed. These monkeys also have unique compartmentalised digestive systems, causing a distinct pregnant-looking belly for both males and females. Proboscis monkeys have unique colouring, changing by sections: red-brown backs and shoulders, cream-coloured chests, and grey arms and legs. Males, larger than females, can grow to 2.5 feet tall with tails of equal length.
Spider monkeys are found throughout Mexican and South American rainforests. Their long arms, legs, and tails give these somewhat large monkeys -- weighing up to 10.9 Kilogram when fully grown -- their names. Twelve species exist in these areas, three of them endangered due to the loss of their habitats. These monkeys are also hunted by humans. Spider monkey fur varies in colour and can be black, brown, red, tan, or golden. They are most often found in the canopy, feeding on fruit and seeds.
Capuchins are small monkeys, usually less than nine pounds. They inhabit the tropical rainforests of Central and South America. There are around 24 species of capuchin monkeys. Most live in groups of up to 35, led by a dominant male. Capuchins are intelligent monkeys and communicate with one another using calls. They live in the forest canopies, jumping as far as nine feet from tree to tree and sleeping on branches. They only come to the ground to find water.