Mark Bowler / Common Squirrel Monkey (Saimiri sciureus ssp. macrodon) in tree, calling, Peru, captive

Roy Mangersnes / Wild Bolivian / Peruvian Squirrel Monkey (Saimiri boliviensis) female carrying young on her back. Madidi National Park, Bolivia.

Roy Mangersnes / Wild Bolivian / Peruvian Squirrel Monkey (Saimiri boliviensis) in tree. Madidi National Park, Bolivia.

Kevin Schafer / Central American / Red-backed squirrel monkey (Saimiri oerstedii) mother carrying baby on her back, Costa Rica, Vulnerable species

Pete Oxford / Common squirrel monkey {Saimiri sciureus} Manu NP, Amazonia, Per

Pete Oxford / Common squirrel monkey {Saimiri sciureus} Amazonia, Brazil

Pete Oxford / Squirrel monkey {Saimiri sciureus} investigates camera. Amazonia, Ecuador

Cyril Ruoso / South American Squirrel Monkey (Saimiri sciureus) portrait, Peru

Cyril Ruoso / Bare-eared Squirrel Monkey (Saimiri ustus) in tree, Peru

Michael & Patricia Fogden / Black-crowned Central American Squirrel Monkey (Saimiri oerstedii) male in rainforest, Costa Rica

Gerry Ellis / South American Squirrel Monkey (Saimiri sciureus), Monkey Island, Amazon Basin, Brazil

David Pattyn / Black-crowned Central American squirrel monkey (Saimiri oerstedii) pair playing with each other. Close-up Manuel Antonio National Park, Quepos, Costa Rica

David Pattyn / Black-crowned Central American squirrel monkey (Saimiri oerstedii) pair playing with each other, on with hand over mouth of other, Manuel Antonio National Park, Quepos, Costa Rica

David Pattyn / Black-crowned Central American squirrel monkey (Saimiri oerstedii) pair playing with each other Manuel Antonio National Park, Quepos, Costa Rica

David Pattyn / Black-crowned Central American squirrel monkey (Saimiri oerstedii) pair playing with each other Manuel Antonio National Park, Quepos, Costa Rica

David Pattyn / Black-crowned Central American squirrel monkey (Saimiri oerstedii) pair playing with each other, one with hand over eyes of other, Manuel Antonio National Park, Quepos, Costa Rica

David Pattyn / Black-crowned Central American squirrel monkey (Saimiri oerstedii) in a tree Manuel Antonio National Park, Quepos, Costa Rica

David Pattyn / Black-crowned Central American squirrel monkey (Saimiri oerstedii) pair close-up Manuel Antonio National Park, Quepos, Costa Rica

Enrique Lopez-Tapia / Hornbills, baboons, snakes, birds, chameleons, hedgehogs, frogs and squirrels for sale at the voodoo market in Abomey, Benin, West Africa. Any wild animal that runs, flies, jumps or crawls is hunted t...

Laurie Hedges / Slow motion shot of three Common squirrel monkeys (Saimiri sciureus) interacting and grooming, Amazon, Brazil. Captive.

Bernard Castelein / Black-capped squirrel monkey (Saimiri boliviensis peruviensis), Pampas del Yacuma Protected Area, Bolivia

Bernard Castelein / Black-capped squirrel monkey (Saimiri boliviensis peruviensis), Pampas del Yacuma Protected Area, Bolivia

Bernard Castelein / Black-capped squirrel monkey (Saimiri boliviensis peruviensis), standing on branch, Municipal protected area of Pampas del Yacuma, Bolivia

Bernard Castelein / Black-capped squirrel monkey (Saimiri boliviensis peruviensis), Pampas del Yacuma Protected Area, Bolivia

Bernard Castelein / Black-capped squirrel monkey (Saimiri boliviensis peruviensis), Madidi NP, Bolivia

Bernard Castelein / Black-capped squirrel monkey (Saimiri boliviensis peruviensis), Madidi NP, Bolivia

Bernard Castelein / Black-capped squirrel monkey (Saimiri boliviensis peruviensis) feeding,, Madidi NP, Bolivia

David Pattyn / Common squirrel monkey (Saimiri sciureus), Cuyabeno wildlife reserve, Sucumbios, Ecuador, July

David Pattyn / Common squirrel monkey (Saimiri sciureus) two sleeping in the late afternoon sunlight, Cuyabeno wildlife reserve, Sucumbios, Ecuador, July

David Pattyn / Common squirrel monkey (Saimiri sciureus) two resting in the late afternoon sunlight, Cuyabeno wildlife reserve, Sucumbios, Ecuador, July

Alex Hyde / Common Squirrel Monkey (Saimiri sciureus) troop moving through rainforest canopy at dawn. Manu Biosphere Reserve, Peru. November.

Nick Garbutt / Squirrel monkey (Saimiri sciureus) feeding on fruit in rainforest canopy. Manu Biosphere Reserve, Amazonia, Peru.

Nick Hawkins / Black-crowned Central American squirrel monkey (Saimiri oerstedii) sitting on branch, Corcovado National Park, Osa Peninsula, Costa Rica, Vulnerable species.

Nick Hawkins / Black-crowned Central American squirrel monkey (Saimiri oerstedii) sitting on branch, Corcovado National Park, Osa Peninsula, Costa Rica, Vulnerable species.

Lucas Bustamante / Common squirrel monkey (Saimiri sciureus) on branch, Yasuni National Park, Orellana, Ecuador.

Lucas Bustamante / Two Common squirrel monkeys (Saimiri sciureus) sitting side by side, Yasuni National Park, Orellana, Ecuador.

Lucas Bustamante / Common squirrel monkey (Saimiri sciureus) climbing along branch, Yasuni National Park, Orellana, Ecuador.

Lucas Bustamante / Two Common squirrel monkeys (Saimiri sciureus) amongst vegetation, Yasuni National Park, Orellana, Ecuador.

Lucas Bustamante / Common squirrel monkey (Saimiri sciureus) walking along branch, Yasuni National Park, Orellana, Ecuador.

Bernard Castelein / Black-capped squirrel monkey (Saimiri boliviensis peruviensis) in tree, Madidi National Park, Bolivia

Bernard Castelein / Black-capped squirrel monkey (Saimiri boliviensis peruviensis) in tree, Madidi National Park, Bolivia

Bernard Castelein / Black-capped squirrel monkey (Saimiri boliviensis peruviensis) in tree, Madidi National Park, Bolivia

Bernard Castelein / Black-capped squirrel monkey (Saimiri boliviensis peruviensis) in tree, Madidi National Park, Bolivia

Bernard Castelein / Black-capped squirrel monkey (Saimiri boliviensis peruviensis) in tree, Madidi National Park, Bolivia

Bernard Castelein / Black-capped squirrel monkey (Saimiri boliviensis peruviensis) in tree, Madidi National Park, Bolivia

Bernard Castelein / Black-capped squirrel monkey (Saimiri boliviensis peruviensis) in tree, Madidi National Park, Bolivia

Bernard Castelein / Black-capped squirrel monkey (Saimiri boliviensis peruviensis) in tree, Madidi National Park, Bolivia

Bernard Castelein / Black-capped squirrel monkey (Saimiri boliviensis peruviensis) in tree, Madidi National Park, Bolivia