Spider monkeys are primitive monkeys of the New World. The males and females look like each other. They are usually all black, though some have rings around their eyes of a flesh color, and white whiskers on their chin. Their hair is generally stringy and coarse and they don’t have any underfur. Their color can be golden, buff, red, brown, or black, while their hands and feet are usually black. They depend very much on their good binocular vision. Their bodies and limbs are slender and they have long narrow hands. Their muscular, tactile prehensile tail is used as an extra hand. Their hands are like hooks, and their palms are long and narrow, with long curved fingers but no thumb. They do have thumbs on their feet. Their head is small, with a prominent muzzle.
The natural environment of this monkey includes Mexico’s southern tip and scattered areas of Brazil. They inhabit huge rainforest areas, as they need a large home range. They also seek areas with a canopy, and prefer wet areas but will settle for drier locations.
Spider monkeys are social animals and form groups of about thirty individuals, with groups of as many as 100 having been reported. Usually, large groups divide into smaller subgroups for foraging and the whole group is together for only a few weeks of the year. Males may forage together in small groups, while females and offspring will often forage alone. They live mainly up in the tree canopy, foraging there during the day, tending to eat a lot in the early morning, resting for the rest of the day. They make their way nimbly along the branches, walking on the upper surfaces, and can use their tails to pick things up. These monkeys "bark" when they are threatened, and when they are approached by humans will throw branches, shake tree limbs and jump up and down.
Spider monkeys are polygynous, one male mating with multiple females. The female monkeys are very particular about who they will mate with and may reject several of them before making their selection. There is no set season for mating for this species, the females being in control of the timing. Gestation lasts for about 7 to 8 months. A female will bear one infant about every two years and is the only one who looks after the baby. They will spend time exploring, or chasing, wrestling, and jumping on other monkeys. The baby is carried by the mother continuously, clinging to her. At about 5 months old it will ride on its mother’s back, wrapping its long tail around its mother’s for added security. Weaning takes place at around 2 years. Males reach reproductive maturity after 5 years of age and females after 4 years old.
Spider monkeys are eaten by many people of Central and South America. They are captured for the pet trade. Their habitat is being destroyed, particularly by logging, which cuts down the tall trees they depend upon. They have low reproduction and maturation rates. Three spider monkey species: the brown-headed spider monkey, the white-bellied spider monkey, and the white-whiskered spider monkey are on either USESA or IUCN’s list as endangered. Black spider monkeys and black-handed spider monkeys are listed by ICUN as vulnerable. The black-faced black spider monkey is the only one considered to be a lower risk (CITES II.)
The IUCN Red List and other sources don’t provide the number of the Spider monkey total population size. Generally, the population trend for Spider monkeys is decreasing. According to the IUCN Red List, one species is listed as Vulnerable (VU), four species as Endangered (EN), and two species as Critically Endangered (CR).
The Black spider monkey has an essential role in the tropical rainforest ecosystem. It has a key role in the dispersal of seeds, helping the environment grow and thrive.