If you're lucky enough to see this endangered monkey species swinging through the canopy, you'll be treated to an acrobatic display of flying leaps and reaching limbs.
Spider Monkeys are named for the length of their limbs, including their tail which is the strongest and most prehensile of any monkey. They prefer to live high in the canopy and to see them move so quickly and with such agility through the branches, using vines like a spider might her thread, one can see that they are aptly named.
A Diet of Fruit
Most of their diet consists of fruit, though also leaves, flowers, insects, decayed wood and honey. Fruit, even in Costa Rica, is seasonal and the monkeys have to travel long distances to find enough food to sustain them. Unlike Howler Monkeys they only rest for about 15% of the day.
A Life in the Trees
Spider Monkeys have specially adapted limbs to allow them to move quickly and easily through forests. Their tails are used like any other limb and have a fanlike bald area below the tip to help with grip. They can use their tails to pick fruit, grab branches, move themselves forward and even as a scoop for water. Spider monkeys have no problem hanging their full weight (up to 15 pounds) by their tail. They use their limbs for swinging branch to branch and have no real thumb, in swinging it would only get in the way, using their strong fingers to grip and eat with.
A Community of Spiders
Communities can be large – up to 45 individuals, but unlike many other species the community tends to divide into smaller groups of around 6 and the groups tend to be single-sexed units. This makes foraging for food easier as groups can move quickly and lightly from tree to tree: very few fruit trees will ripen all at once so working in small groups is better for both monkeys and vegetation. Male groups will tend to patrol the periphery of a troop’s large range while females, especially females with young, will remain in the center of the territory. Small groups usually come together at night to sleep. Unlike many other monkey species, it is the females who leave their birth group to search out new troops. Males remain within their birth group.
Communication
The Spider Monkey communicates through a series of barks, whinnies and screams; it is believed each monkey has its own distinctive whinny and can be recognized by voice alone. This is important when the monkeys are spread out in subgroups through a large area. Like Howlers each group will herald its position at dawn and dusk through a chorus of noise.
Role in the Ecosystem
Spider Monkeys are very important in seed dispersal; their movement means that seeds are often dispersed far from the parent tree. Indeed several varieties need Spider Monkeys to germinate their seeds. Digestion is a quick process and seeds leave the digestive tract intact with a fine accompaniment of manure.
Endangered Species
The shrinking forests of Costa Rica have affected the habitat of Spiders: their diet demands a broad area and with new developments breaking up the canopy cover the monkeys are becoming more restricted in their territories – higher demands are thus made on fewer trees which sadly often results in starvation or seriously reduced numbers. Spider Monkeys are still hunted in some parts of the country despite international law protecting them; likewise there is a trade in Spider Monkeys as pets which is now also illegal. The monkeys themselves have a very low reproduction rate – females give birth only every 2 to 4 years meaning that even with protection and safe habitat it can take many years for groups to become re-established and reach a healthy size.
