Photos From Costa Rica!

I had the pleasure of conducting my research at Piro Biological Station in the Osa Peninsula, Costa Rica. I was there to look at foraging ecology in howler monkeys (Alouatta palliata), specifically I was trying to see if they deplete preferred patches of food.

At this field site there are four species of primates:


Central American Squirrel Monkey (Saimiri oerstedii)

This species of squirrel monkey is small, averaging around 600-900g. They spend most of the day chasing down and feeding on insects. Groups can be quite large, up to 100, but 25-75 is usually more frequent. Mating and births are highly seasonal and females are sexually receptive one or two days in the mating season.


Black-Handed Spider Monkey (Ateles geoffroyi)

Spider monkeys are highly suspensory, moving by brachiation and arm-swinging. They also have a prehensile tail which works as an extra limb, able to hold their entire body weight. They are highly frugivorous, but will consume other food sources when fruit is sparse. They generally live in groups of 20-30, but break off into smaller groups to reduce feeding competition.


White-Faced Capuchin (Cebus capucinus)

White-faced capuchins consume a wide variety of foods and due to this are often described as “opportunistic foragers”. They are usually found in multi-male/multi-female groups of 10-20 with a distinct hierarchy. Alpha males help protect group members from other neighboring groups and predators. They are highly intelligent and highly social.


Mantled Howler Monkey (Alouatta palliata

Mantled howlers get their name partially from the beautiful blond mantle at their sides. These monkeys feed mostly on leaves, but also consume a large amount fruit in the rainy season. They have a prehensile tail which helps them traverse through the forest, but also assists in freeing their hands while they forage. They spend a lengthy portion of their day resting so that they can digest the plant matter they consume. One of their coolest behaviors makes up the second part of their name: “howler”. Male howlers have a specialized “voice box” that allows their howls to be heard at distances of 1-2km. It’s quite amazing if you’ve never heard it before!! Other members of the group will join in as well, but their voices don’t quite reach the volume of the dominant male(s).

I also had the pleasure of seeing a few other cool animals:

Coati (Nasua)


Anole (Anolis)


Green Turtle (Chelonia mydas)


Chestnut-mandibled Toucan (Ramphastos ambiguus swainsonii)


I saw many more animals than these pictured, but many of those moments happened too quickly to catch on camera. I will treasure them!

The Osa Peninsula is a beautiful place, rich in biodiversity (2.5% of the world’s!). I only hope that more research can come out of this species diverse area!

Featured Image, courtesy of Osa Conservation

Other photos, courtesy of Jessica Ritsche (myself)

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