Spider Monkey - Anatomy and Physiology

Anatomy and Physiology

Spider monkeys are among the largest New World monkeys; black-headed spider monkeys, the largest spider monkey, have an average weight of 10.8 kg (24 lb) for males and 9.66 kg (21.3 lb) for females. Disproportionately long, spindly limbs inspired the spider monkey's common name. Their deftly prehensile tails, which may be up to 89 cm (35 in) long, have very flexible, hairless tips and skin grooves similar to fingerprints. This adaptation to their strictly arboreal lifestyle serves as a fifth hand. When the monkey walks, its arms practically drag on the ground. Unlike many monkeys, they do not use their arms for balance when walking, instead relying on their tails. The hands are long, narrow and hook-like, and have reduced thumbs. The fingers are elongated and recurved.

Their hair is coarse, ranging in color from ruddy gold to brown and black; the hands and feet are usually black. Heads are small with hairless faces. The nostrils are very far apart, which is a distinguishing feature of spider monkeys.

Spider monkeys are highly agile, and they are said to be second only to the gibbons in this respect. They have been seen in the wild jumping from tree to tree.