Brown Spider Monkey

## Description

The Brown spider monkeys are distinguished from other species of their genus by considerably long legs and the habit of climbing. Currently, these primates are a popular pet species, representing 'typical small monkeys', according to the opinion of many people. Unfortunately, these adorable creatures are threatened with total extinction, which may happen one day. However, many efforts are presently put to save this unique species. Another important characteristic of the Brown spider monkeys (and generally, all spider moneys) is the thin, powerful and prehensile tail, which acts as an extra leg, due to which the species of this genus are named. Individuals in the wild live 27 years on average. Meanwhile, those in captivity are known to outlast them for 10 or more years.

## Distribution

The natural range of this species covers northern Colombia and north-western Venezuela, where The Brown spider monkeys live in two defined sup-species: the Hybrid spider monkeys, inhabiting the area from the right bank of the Rio Magdalena (Colombia) to western Venezuela; and another subspecies (A. h. brunneus), found from Cauca to Magdalena River in Colombia and occasionally considered to be synonymous. Preferred types of habitat are mainly subtropical and tropical rainforests, sometimes - riverine, marsh and semi-deciduous forests. As tree-dweling primates, these animals live in old, tall trees. They are most frequently found in the upper areas of forest canopy.

## Behavior

The Brown spider monkeys lead a diurnal lifestyle, being active by day and sleeping by night. These primates are highly social animals, forming fission-fusion units, consisting of multiple individuals of both genders. During the day, these groups may split into smaller sub-groups of 2 - 30 individuals, which keep contact with each other through ‘ts chookis’, whoops, wails and other vocalizations. After a while, these sub-groups come together, and the monkeys greet each other with immense excitement, giving out various vocalizations, chasing, hugging with tails entwined as well as sniffing of the sternal glands of one another. Spider monkeys in general don't have any defined social hierarchy, although individuals are occasionally ranked by age. As for the Brown spider monkeys, these animals don't display any kind of hierarchy. They usually travel and feed in groups: while males travel in single-sex groups, females travel with their young.

## Diet

Being frugivores, throughout the year, these primates generally maintain a fruit-based diet. However, during the dry season, fruits are sometimes hard to find, and the Brown spider monkeys often consume young leaves, flowers and seeds, bark, honey, decaying wood as well as occasional termites and caterpillars.

## Reproduction

There is very little information of the reproductive system of this species. However, like other species of their genus, the Brown spider monkeys are believed to exhibit polygynandrous (promiscuous) mating system: this is when both males and females have numerous mates. These primates don't exhibit a certain mating season, although most births occur in May-July, during the early rainy season. Females produce offspring at intervals of 3 - 4 years. A single infant is born after 226 - 232 days of gestation. During the first two months of its life, the baby clings to the belly of its mother, after which it moves to her back. The young monkey feeds upon maternal milk for one year or more, although captive individuals may be weaned at up to 20 months old. The age of maturity is approximately 4 - 5 years old. Females of this species are known to produce their first young at 7 - 8 years old.

## Population

### Population threats

The Brown spider monkeys heavily suffer from pet trade and illegal hunting. These animals presently face fragmentation and degradation of their forest habitat due to development of agriculture, roads and human settlements. For example, the tiny forest range of Brown spider monkey subspecies (A. h. brunneus) is currently undergoing loss, degradation and fragmentation.

### Population number

The IUCN Red List and other sources don’t provide the number of the Brown spider monkeys’ total population. Currently, this species is classified as Critically Endangered (CR) and its numbers continue to decrease.

### Ecological niche

Brown spider monkeys play a very important role in the ecosystem they live, as they disperse seeds of fruits and plants they consume.

## Fun Facts

The eyes of these monkeys are usually light brown, although individuals occasionally exhibit pale blue eyes.

Spider monkeys are so called due to the habit of using their long tail as a 'fifth limb', helping them grip branches when moving around trees and making them look like big spiders.

Because of their tree-dwelling lifestyle, spider monkeys lack a thumb, having 4 curved fingers on each hand, resembling a hook.

When two groups of these animals meet, members of these groups typically greet each other by hugging, which allows to avoid undesired conflicts or aggression between individuals.

The brain of these intelligent animals weighs 107 g. Meanwhile, their brain is the same size but twice as heavy as that of the howler monkeys.

Spider monkeys are known to have special sleeping sites that are home to these animals and are located in trees. They tend to sleep in the same place every night.