The spider monkey is the largest primate inhabiting the Neotropical rainforests in Costa Rica. Due to this aspect, their role is substantial in dispersing seeds across their surroundings.

The Process of Seed Spread

Apart from just falling off from the plants, seeds have an ingenious and highly efficient way to spread themselves around in the environment to give rise to new generations. Some seeds have hooks and burrs that attach themselves to passing animals' fur. Other than that, many seeds are edible, and when the animals eat them, they carry them in their bellies as they move about before excreting them elsewhere in their excrement.

- Ingestion: The spider monkeys consume various fruits and seeds that are part of the plant they live in, which is essential in the dispersion of seeds. In their foraging activities in the canopy, these primates only feed on matured fruits. Usually, the entire seed is swallowed, or they spit it out after removing the pulp.

- Transportation: Spider monkeys are observed to cover long distances within their home ranges, occasionally exceeding ten kilometers daily. Such extensive movements assist in seed dispersal by transferring seeds away from the parent tree, reducing competition, and allowing colonization of new areas.

- Seed dispersal: After being digested in the monkey’s digestive system, the seeds are excreted into open spaces, the understory of a forest, or even inside holes in fallen trees. Various conditions, including light availability, soil type, and moisture level, determine whether germination can take place.

- After the seed is dropped, growth and germination begin; this new life cycle has just started. Researchers have observed that the germination rate of seeds spread by spider monkeys is much higher, and they also grow quicker than seeds falling directly from the parent tree.

- Spreading seeds across ecosystems, not just trees, is an ecological impact of spider monkeys. Spider monkeys help forests grow back by spreading seeds over long distances and through various habitats. They also help keep genetic diversity high and plant groups strong in the face of environmental changes.

It’s essential to understand this species because it also helps the biodiversity of the tropical forest and the maintenance of other species.