Costa Rica is a country blessed with a plethora of wildlife. With just 51,100 square kilometres, this territory protects approximately 5% of the world’s biodiversity in its wild landscape. This small and contrasting country also houses an important number of Central America’s primate biodiversity. there are four different primates in Costa Rica: Howler monkey (Alouatta palliata), Spider monkey (Ateles geoffroyi), White-faced monkey (Cebus imitator) and Squirrel monkey (Saimiri oerstedii).
Each of these monkeys are found in different quantities throughout the country. Some are even locally extinct, as it occurs with the spider monkey in Cabo Blanco Reserve on the Nicoya Peninsula. Others only exist in some parts of the territory, like the case of the squirrel monkey which is only found in the Central and South Pacific slopes of Costa Rica’s lowlands, and on a small part of Northwestern Panamá near the Costa Rican border; making this beautiful monkey endemic to this region and of global importance.
In the Central Pacific, Squirrel Monkeys find their habitat every day more encroached by industrial palm oil, development for tourism, highways, electric wires, and other human activities that pose risks for their future conservation. On the other hand, we have the populations on the Osa Peninsula. This region is a very remote corner of the country that harbors 50% of Costa Rica’s biodiversity, and contains the largest population of Central American Squirrel Monkeys. The population on the Osa Peninsula is much more robust compared to other regions where the squirrel monkey resides.
The Osa Peninsula is located on the most southern point of Costa Rica’s mainland (only Cocos Island is more south) and this fact has helped protect it from excessive development and industrial farming. Although promising, there are still threats to Squirrel Monkey habitat in the Osa Peninsula. For example, the lack of opportunities for the people, especially the younger generations, has led to illegal activities such as poaching and illegal logging to escape poverty.
Despite the problems this territory might have, when I arrived at the Osa Peninsula in 2004, studying Conservation and Wildlife Management, the simplicity of the inhabitants and the beauty and wilderness of the landscapes, stole my heart forever.
For this reason, it is here where I founded my organization, Saimiri Foundation, with the goal to protect all primate species. I have been working for the last 10 years to raise awareness about this small, but important monkey. During these years, we have focused on teaching the importance of Squirrel Monkeys and all wildlife through environmental education, as well as producing relevant scientific data.
I love sharing my knowledge with people from around the globe, but mostly with the children of my community, who remind me of the young members within squirrel monkey troops, always looking for new adventures with bright shiny eyes and ready to play. I also love to see the transformation of the volunteers that help me hand in hand collecting data on what the tiny voracious little monkeys eat and do. After a week in the forest, living amongst the lush jungle and witnessing the simplicity with how people in this corner of the country live, the volunteer’s lives are altered.
With our observations, we have been able to document a variety of food items consumed by the squirrel monkey. Cacti, epiphyte fruits, insect foamy eggs, delicious figs, and crunchy grasshoppers are just some of the foods these tiny monkeys feast on. Weighing on average one kilogram and measuring no more than 30cm long (add 39 cm with their tails), squirrel monkeys sweep each leaf and branch found in their path in search of food.
All Costarican primates have different important ecological roles, seed dispersion is one of the most important roles. At Fundacion Saimiri we have discovered that the Squirrel Monkey plays a major role as a gardener and restorer of the forest on the Osa Peninsula. On the Osa, as well as other areas they inhabit, these small monkeys prefer secondary growth forest. Secondary forest consists of an array of vegetation that grows after deforestation, or natural disaster. Little by little, by eating fruits and sweeping the forest in search of insects, the squirrel monkey disperses the seeds of more than a hundred species of trees in their droppings. This was documented in our latest research with the help of expert botanist Reinaldo Aguilar Fernández, who has been studying the flora of the Osa Peninsula for the last 30 years.
Almost all fruit tree species eaten by the squirrel monkeys produce fruit during the peak of the dry season. It is also during that time that Squirrel Monkeys give birth. This is a well-documented phenomenon amongst Squirrel Monkeys. All birthing occurs over a two-month period, between the last days of January and the months of February and March. Although, during a five-day period in mid-February most babies are born.
Many monkeys have birthing peaks that correspond to food availability. Such highly synchronized birthing reduces infant mortality. The infants are especially vulnerable to predators, including hawks, falcons, toucans, boas and possibly felids, some local researchers have also seen White-faced Monkeys predating newborns. Thus, females associate closely with one another to form protective alliances among themselves to watch for predators.
It is important to notice, once again, the main trees used for food by Squirrel Monkeys. In the last 15 years that I have lived on the Osa and have been passionate about Squirrel Monkey, I noticed their preferences for palms, particularly the wild heart of palm (Astrocaryum standleyanum). It is a very important palm for the indigenous cultures of the Pacific coast of Central and South America. The tiny squirrel monkeys avoid predators by sleeping on the ends of palm tree fronds at night, they shake with minimum movement and the trunk has very sharp spikes that deter the most agile predators.
It is not easy for them either. They need to be extremely careful while climbing to this protective shelter. They do so by utilizing the tree’s hanging fruits, or by jumping from the crowns of adjacent palms. The reward is a more tranquil night of rest. The rest is much needed, as they can wander seven km per day looking for insects and fruits.
To study these monkeys, one must become an early bird and be fit. The best spot to start following the monkeys is at the tree they slept on during sunrise. This is a hectic moment in the forest when the first rays of light peak beyond the horizon and the jungle comes to life. You have to be an avid walker as monkeys will sweep the forest in their search for food and they normally do it quickly.
Their path will take you up and down many hills and by the end of the day you will have perspired last drop of sweat in your body. As the sun sets and they look for their sleeping site for their night’s rest, you will feel extremely satisfied but also ready for a shower, a home cooked meal, and a hammock.
Although hard and difficult, fewer moments give me such joy. Walking through the forest, with the sunlight sneaking timidly between the treetops and reflecting a mystical gold shine on the bushes, makes me content. Then, when I hear in the distance the chirps of a playful troop of squirrel monkeys, I know I can’t ask for more, and I cherish that moment forever. It gives me energy to keep working toward the conservation of these cute endemic and endangered primates and the communities that coexist with them.
