Crab-eating monkeys, also known as long-tailed monkeys and Java monkeys. Mainly produced in Thailand, Laos, Vietnam, Cambodia, Myanmar, Malaysia, Indonesia, the Philippines and Nicobar Island, India, in Southeast Asia, many small islands are distributed, inhabiting the tropical rainforests, mangrove swamps, tidal rivers along the coast and other tropical islands, seashore. It is a second-class national key protected animal, because it likes to forage for crabs and shellfish on the seashore after low tide, so it is called crab-eating monkey.

Crab-eating monkeys are smaller than rhesus monkeys, with hair color varying from yellow, grey and brown, and light white abdominal hair and inner limbs; crown hairs are back-draped, with whiskers on the face, and the skin around the eyes is bare, and there are white triangles on the upper side of the eyelids; the ears are erect and the eyes are black.

Crab-eating monkeys are widely used as experimental animals in medical research. According to the November 2007 statistics of China Experimental Primate Breeding and Development Association, there are 32 experimental monkey breeding enterprises in the country, of which 9 are in Guangxi, 7 are in Guangdong, 4 are in Yunnan and 3 are in Hainan. The national stock of experimental monkeys is 145,000, including 120,000 crab-eating monkeys and 25,000 rhesus monkeys.