The spider monkey is an endangered primate. It is a diurnal animal. They form large social groups of about 20 individuals, but generally feed in small groups of 1 to 5 depending on environmental conditions and it is very rare to see the entire social group, then separate into smaller groups during the day, about three individuals, when they go in search of sustenance and move according to food availability.
Depending on the species, the body length is from 35 to 75 cm in length, and the prehensile tail of 60 to 92 cm. It weights 6 to 10 kg. Have four fingers and thumb lacking. The body is thick; the color of the different species varies from light brown to black. The arms and legs are long. They are used to climb and hold onto the branches with facility. The tail is prehensile and used an extra tip. The inner part of the tail, from the middle to the tip, does not mince; the skin has the same texture as the palms of the hands.