Eye Spy…A Spider Monkey?!

Just the other week, a few UGA Costa Rica interns spotted monkeys while hiking the trails around campus. Seeing a white-faced capuchin monkey is reason enough to do a happy dance, but after getting a closer look, the naturalists realized they were in the presence of spider monkeys – an incredible rarity to spot on campus.

So much so, that no member of the UGA Costa Rica staff can recall ever having seen the orange-tinted primates on campus trails.

The Central American Spider Monkey is among the most active and agile of cebids, (family Cebidae) or New World monkeys. Part of the reason for their activeness is body morphology; their forelimbs and fingers are longer than other monkeys’, and they have a vestigial, or underdeveloped, thumb – it just gets in the way of swinging! Having a prehensile tail sure does help with agility, too. It’s like having a fifth arm. A spider monkey’s prehensile tail is not only defter than other monkey tails, but it also has exposed skin on the underside, like a no-slip grip with which it confidently grasps branches.

Spider monkey diets mainly consist of fruit. Because of the sugars in fruit, they are high-energy, moving quickly and frequently in the canopy in order to find more of their sporadic source of food. To make up for the lack of protein in the fruits, spider monkeys may eat young leaves and decaying bark.

So why all the rave about spotting spider monkeys at UGA Costa Rica?

A species’ reappearance (and disappearance) is often an indicator of environmental changes – both good and not so good. No one is entirely sure why the spider monkeys are here, and whether or not it’s an optimistic find, but there are a number of theories germinating around campus…

The more commonly seen white-faced capuchin monkeys, recognized for their aggressive and territorial behaviors, may have been quite defensive of their UGA Costa Rica territory in the past, thus keeping spider monkeys at bay. The first theory then, is that perhaps the dynamic between monkey groups has recently been changing and the two species are learning to overlap territories?

Another hypothesis is that the monkeys are following their food source. With changing climate, there’s a chance fruit dispersal patterns are deviating from the norm, and spider monkeys are adapting locations as a result.

Over lunch, I chatted about a third, and seemingly promising theory with Jheudy Carballo, a tour guide leading the Morganton Day School throughout Costa Rica. Having worked as a guide for the past 16 years, Carballo raised his eyebrows when I mentioned the spider-monkey sighting. First, he mentioned that he has seen spider, howler, and white-faced capuchins all in one tree, and therefore doesn’t think the sighting is a result of territorial cease-fire.

According to Carballo spider monkeys were supposedly wiped out of the Monteverde region by yellow fever in the 1970s. Their population has since been bouncing back, and it’s possible that they are now expanding their territory from the Monteverde Reserve area into the UGA Costa Rican cloud forest in order to maximize on food availability. He also mentioned that a growing population is indicative of a rejuvenating forest.

Bienvenidos to the spider monkeys!

Blog post contribution by Alex Fylypovych, UGA Costa Rica Photojournalism intern

Photo contribution: Will Booker, UGA Costa Rica Moth Researcher

2 thoughts on “Eye Spy…A Spider Monkey?!

  1. I know of no data to suggest that either spider monkeys or capuchins show territoriality towards other species. Carballo is likely correct. Was there documentation of Yellow fever wiping out spider monkeys in the 1970’s? I would suspect hunting. They are regularly hunted in Colombia and there is more meat on a spider monkeys and the babies can be sold. (Illegal, but profitable.) Perhaps reforestation and corridors can take the credit for Ateles in San Luis. Now where are the howlers? They are at Santa Helena so…..

    • Howlers have been heard and spotted on campus as well. I believe beginning around the same time the Spiders were seen, and we still hear them regularly.

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