The Black-headed spider monkey is native to Central and South America. This primate belongs to the group of New World monkeys. This species is composed of two sup-species, differing in their color pattern: Brown-headed spider monkeys, which exhibit brownish-black overall fur and a brown head; and Colombian spider monkeys that are totally black, displaying only a few white patches on their chin. The Black-headed spider monkeys are excellent climbers and have a strong grip due to lacking a thumb.
The natural range of these animals covers some parts of Central and South America. While the Brown-headed spider monkeys are generally found in Ecuador (and possibly, in Columbia), the Colombian black spider monkeys occupy a territory from south-western Colombia to eastern Panama. Both of these sub-species live in dry forests as well as humid and cloud forests. Populations in Ecuador are most frequently found in wetter forests such as tropical and subtropical humid forests.
The Black-headed spider monkeys are diurnal, mainly arboreal and very social animals. These primates are known to form large fission-fusion groups of 20 - 100 monkeys, composed of multiple males and females. When feeding, these groups split into smaller sub-groups. Spending the majority of their time in trees, they rarely descent to the ground. When travelling among trees, they swing on all of their four legs. When moving along branches, they usually walk in an upright position. These agile animals are excellent leapers, capable of taking long leaps of up to 9 m (30 ft.), when moving between branches. They communicate through vocalizations such as a high-frequency whinny.
Little is known about the mating behavior of Black-headed spider monkeys. It is known, however, that when mating, females may stay with a male for around three days and may mate with several males. It means that this species may exhibit either polygynandrous (promiscuous) (both males and females breed with multiple mates) or polyandrous (one female mates with several males in a breeding season) mating systems. All spider monkeys are able to breed at any time of the year. Females usually produce offspring at intervals of 3 years. The gestation period lasts between 226 and 232 days, after which a single infant is born. The newborn baby will ride the back of its mother until 16 weeks old. Weaning occurs at 20 months of age. After reaching adolescence, females leave their natal group, whereas males continue living with the group throughout their lives. The age of sexual maturity is 51 months old in females and 56 months old in males.
The Black-headed spider monkeys are nowadays threatened by deforestation, which negatively affect the overall population of this species. Although some populations still inhabit partially logged forests, hardly any group can be found in areas, where the rainforest habitat is totally wiped out. Additionally, localized threats include hunting for food.
The IUCN Red List and other sources don’t provide the number of the Black-headed spider monkeys’ total population. According to the Tropical Conservation Science resource, the total population of the Brown-headed spider monkey subspecies is around 250 individuals in northwestern Ecuador. Overall, Black-headed spider monkeys are classified as Critically Endangered (CR) and their numbers are decreasing.