The black-headed spider monkey (Ateles fusciceps) is a type of New World monkey, from Central and South America. It is found in Colombia, Ecuador, and Panama. Although primatologists such as Colin Groves (1989) follow Kellogg and Goldman (1944) in treating A. fusciceps as a separate species, other authors, including Froelich (1991), Collins and Dubach (2001) and Nieves (2005) treat it as a subspecies of Geoffroy's spider monkey. The two subspecies are: Ateles fusciceps fusciceps - northwestern Ecuador. Ateles fusciceps rufiventris - southwest Colombia to eastern Panama. A. f. fusciceps lives in tropical and subtropical humid forests between above sea level. It lives in population densities of 1.2 monkeys per square kilometer. A. f. rufiventris lives in dry forests, humid forests and cloud forests, and can live up to above sea level. A. f. fusciceps has a black or brown body and a brown head. A. f. rufiventris is entirely black with some white on its chin. The black-headed spider monkey is one of the larger New World monkeys. The head and body length, excluding tail, typically ranges between . The prehensile tail is between . On average, males weigh and females weigh . The brain weighs . The black-headed spider monkey is arboreal and diurnal. It moves by climbing and brachiation. When mating, females may consort with a male for up to three days, or else mate with several males. Mating occurs with the male and female face to face, and can last for five to 10 minutes. The gestation period is between 226 and 232 days. The infant rides on its mother's back for 16 weeks, and is weaned at 20 months. Females attain sexual maturity at 51 months; males at 56 months. Females give birth every three years. The black-headed spider monkey is considered to be endangered by the International Union for Conservation of Nature (IUCN) due to an estimated population loss of more than 50% over 45 years (2018-2063), from hunting and human encroachment on its range of habitation. Captive black-headed spider monkeys have been known to live more than 24 years. Gallery References black-headed spider monkey Primates of Central America Mammals of Colombia Mammals of Ecuador Primates of South America Critically endangered fauna of North America Critically endangered biota of South America black-headed spider monkey black-headed spider monkey