Brown-headed Spider Monkeys have long, narrow limbs and a prehensile tail that is used as a fifth limb to swing between branches as they forage for food. Their tail is much longer in length than their body. The tail measures 70 to 85 cm (28 to 34 in.) while the body ranges from 40 to 55 cm (16 to 22 in.). The average weight for both the male and female is approximately 9 kg (20 lbs.). Brown-headed Spider Monkeys can be separated into two subspecies. The subspecies A. f. fusciceps has a brownish-black body with a brown head. A. f. robustus is completely black except for a few white strands of hair on the chin. Their coat is long and shaggy, usually with a lighter underside. A white ring surrounds each eye. Their skull is structured so that they have forward facing eyes which allow them to precisely gauge distances as they swing from tree to tree. The hands and feet of A. fusciceps are adapted for climbing. Brown-headed Spider Monkey species lacks a thumb, which increases the strength of their grip and helps with climbing (Sleeper 1997; Napier 1985).
Range mass: 0 to 0 kg.
Average mass: 9 kg.
Other Physical Features: endothermic ; bilateral symmetry
Rights Holder: The Regents of the University of Michigan and its licensors
Bibliographic Citation: Cifranic, B. 2002. "Ateles fusciceps" (On-line), Animal Diversity Web. Accessed April 27, 2013 at
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