The Crab-eating Macaque (Macaca fascicularis) is a primarily arboreal macaque native to Southeast Asia. It is also called the Cynomolgus Monkey and the Long-tailed Macaque. The Crab-eating Macaque is found in a wide variety of habitats, including primary lowland rainforests, disturbed and secondary rainforests and riverside and coastal forests of nipa palm and mangrove.
The Crab-eating Macaque Monkey also easily adjusts to human settlements and are considered sacred at some Hindu temples and on some small islands.
The native range of the Crab-eating Macaque includes most of mainland Southeast Asia, including the Malay Archipelago islands of Sumatra, Java and Borneo, the islands of the Philippines and the Nicobar Islands in the Bay of Bengal. Although this monkey is often referred to as the Crab-eating Macaque, its diet is by no means limited to crabs. Other food items are in fact far more common. They are an opportunistic feeding omnivore, meaning they can and will eat a wide variety of animals, plants and other materials, it also eats leaves, flowers, roots and bark. It also preys on bird chicks and nesting female birds, lizards, frogs, fishes and bird eggs.
The Crab-eating Macaque is a very social animal that lives in groups anywhere from 5 - 60 individuals. These groups are multi-male groups, normally containing 2 - 5 males and 2 - 3 times as many females. Their groups are female orientated. They will remain in a a group up to 4 or 5 years and will emigrate several times throughout their life. Crab-eating Macaques have a strict dominance hierarchy. Adult males rank higher than females.
Female Crab-eating Macaques have a gestation period of 167 - 193 days, the female gives birth to one young. The infants weight at birth is approximately 350 grams. Infants are born with black fur and this fur will begin to turn to a yellow-green, grey-green, or reddish-brown shade after about 3 months. Young juveniles stay with the mother and relatives playing together forming bonds that may help them when they emigrate from their natal group. Males that emigrate with a partner seem to be more successful than those that move off alone.
Depending on sub-species, the body length of the adult monkey is 38 - 55 centimetres with comparably short arms and legs. The tail is longer than the body, typically 40 - 65 centimetres. Males are considerably larger than females, weighing 5 - 9 kilograms compared to the 3 - 6 kilograms of female individuals.