Monkey, Geoffroy’s Black-Handed Spider

Spider Monkey at the LA Zoo Photo Credit Jamie Pham

Scientific Name: Ateles geoffroyi geoffroyi

The black-handed spider monkey is a new world primate grouped along with howler and woolly monkeys. There are several subspecies of spider monkeys including Geoffroy’s which resides at L.A. Zoo.

What’s in a Name?

When you see a spider monkey hanging out in the tree tops, supported by its long, slim limbs and prehensile tail, you can understand where it got the name “spider” monkey. Furthermore, black-handed spider monkeys do indeed have black hands. Their feet and tail sensory areas are also black.

Like other monkeys and apes, black-handed spider monkeys have opposable big toes on their feet that can grab onto branches easily. However, their hands are quite different from most other primates. They only have “vestigial” thumbs with hinge joints. That’s right; they don’t have complete thumbs – not anymore anyway! Over many thousands of years, the thumb has evolved away. Most scientists think this has improved the monkey’s hook grip used when swinging through the trees. So, when you observe L.A. Zoo’s black-handed spider monkeys you won’t see any thumbs. But if you look closely, you might notice a tiny stub where a thumb once existed. The spider monkey’s genus refers to its absent thumb; in Greek ateles means “not complete”.

Geoffroy’s black-handed spider monkey is currently listed as Endangered on the IUCN Red List; mainly due to habitat loss. The L.A. Zoo’s black-handed spider monkeys are part of a Species Survival Plan breeding program to help conserve the species.

While black-handed spider monkeys live in Central America from southeast Mexico (Veracruz) to western Panama, Geoffroy’s subspecies is restricted to the mainland of Costa Rica and Nicaragua. Spider monkeys make their homes in emergent trees, in the upper levels of tropical and subtropical rain forests. Sometimes they are found in evergreen, semi-deciduous, and deciduous forests.

Black-handed spider monkeys use their wonderful color vision to select the ripest fruits which comprise most of their diet. Sometimes they also eat young leaves and flowers.

This monkey has very long and slender limbs. Its long prehensile tail is more developed than in any other primate, and is used as a fifth limb. The bare sensory area on the underside of its tip allows it to grip, and that skin is like a fingerprint unique to each monkey. The strong tail can hold on to virtually anything, giving the monkey support when suspended in the tall trees where it spends nearly all of its time. The short body fur may be golden-brown, reddish-brown, or dark brown. While most new world monkeys move through the trees on all four legs or by leaping, spider monkeys also swing from tree to tree using their long forearms, and supported by their prehensile tails. Their long hook-like hands quickly catch branches and vines as the monkey swings through the forest.

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