Ateles geoffroyi
Central American spider monkey

The black-handed spider monkey is found along both coasts of Mexico from Tamaulipas in the northeast and Jalisco in the west south to northwestern Colombia.

Ateles geoffroyi inhabits mature rainforest and montane forest.

Head and body length ranges from 305 to 630mm, and tail length from 635 to 840mm. With respest to body length, Ateles geoffroyi has extremely long limbs and tail. The head is small and the muzzle substantial. The upper fur is black, brown, or reddish and the face is often marked with a pale mask of unpigmented skin around the eyes and muzzle. The arms and feet are dark and the underparts paler (white, pale brown, reddish, or buff). Female spider monkeys have an enlarged clitoris that resembles the penis of males.

Ateles geoffroyi does not appear to have a regular breeding season. Female black-handed spider monkeys have an estrous cycle of 24 to 27 days; mating is restricted to a period of two to three days. Gestation lasts 226 to 232 days and one young is born. Ovulation is suppressed by lactation and births occur at two to four year intervals. Males are sexually mature in five years and females in four. The longest recorded captive lifespan is 33 years.

These animals are social and tend to form groups of approximately thirty individuals. Groups of up to 100 have been reported. For the most part, these large groups split into smaller subgroups to forage and only for a few weeks out of the year is the whole group together. Group size varies with habitat type and seems to depend largely on the productivity of the area.

These spider monkeys live mainly in the top of the tree canopy where they forage diurnally. They tend to feed heavily in the early morning and to rest for the remainder of the day. These monkeys are among the most agile of the primates and are often seen hanging by one limb or by the tail, which essentially functions as a fifth limb. They walk nimbly along the upper surfaces of branches and are able to pick things up with their tails.

Black-handed spider monkeys "bark" when threatened and often throw branches, jump up and down, and shake tree limbs when approached by humans. They emit a sound similar to a whinny when they are separated from one another.

These monkeys eat mainly ripe friut and less frequently leaves and flowers. They may also eat some nuts, seeds, insects, arachnids, and eggs.

Spider monkeys are a source of food for many Central and South American peoples.

This monkey is listed as CITES Appendix I, US-ESA endangered. Apparently it is tolerant of some logging but depends upon large areas of tall forest. It is hunted for food and is locally extinct from most accessible areas. It's large group numbers and noisy habits make this species easy to find.

Some researchers believe that the four allopatric species of Ateles, A. geoffroyi, A. fuscipes, A. belzebuth, and A. paniscus, are all subspecies belonging to the same species, A. paniscus.