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What Is the Mutualism of a Spider Monkey?

Spider monkeys (family Cebidae) are small primates living in the tropical rain forests of South and Central America. They have long, prehensile tails, which they use in traveling through the trees, and spend most of their time in the high canopy of the forests. The diet of spider monkeys consists mostly of ripe fruit, though they will sometimes eat leaves, flowers and seeds when fruit is scarce, as well as termites and caterpillars. They usually live in troops of a dozen or more monkeys, but when foraging they will often split into small groups of two to four.

Mutualism
- Mutualism is a type of symbiotic relationship that is beneficial to both partners. This differentiates it from parasitism and predation, which benefit one partner but harm the other, and commensalism, in which one partner benefits but there is no benefit or harm to the other. Often in mutualistic relationships, one species gains food while the other gains protection from predators or aid in reproduction.
Food and Dispersal
- Spider monkeys play an important role in the rain forests through their mutualistic relationship with the fruit-bearing plants of the region. The monkeys eat the fruit, and disperse the seeds elsewhere in the forest. In some cases this happens when the monkey carries the fruit to another tree and drops it or the seeds, but usually the spider monkey eats the small seeds with the fruit. The seeds pass through the monkey's digestive tract and are dispersed when the monkey defecates.
The Strangler Fig
- One plant that derives immense benefit from this relationship is the strangler fig. This is a plant that germinates on the bark or limb of a tree, then sends roots down to the ground to gain nutrition. Up near the treetops, the plant bears fruit, which the spider monkeys eat. The fruit of the fig contains a mild laxative, so the seeds pass through the digestive system quickly with little damage. The spider monkey then defecates, and the feces lands on a lower limb or on the bark of a tree. The seed is thus planted in the middle of a nutrient-rich pile of manure.
Ecological Importance
- Because of the spider monkey, the strangler fig and other fruit-bearing plants gain a greater rate of survivability by being dispersed over wider areas. The manner in which the monkeys split into small groups for foraging may help to increase this dispersal effect, as the seeds are spread in a more scattered distribution. Because of this relationship with fruit-bearing plants in the American rain forests, the spider monkey plays a key role in maintaining rain forest diversity.

Animals & Science