Roland Seitre / Diana Monkey (Cercopithecus diana), La Vallee des Singes Primate Center, Romagne, France

Roland Seitre / Coppery Titi (Callicebus cupreus), La Vallee des Singes Primate Center, Romagne, France

Roland Seitre / Golden-headed Lion Tamarin (Leontopithecus chrysomelas), La Vallee des Singes Primate Center, Romagne, France

Cyril Ruoso / Chimpanzee (Pan troglodytes) knuckle-walking through grass, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Chimpanzee (Pan troglodytes) pair napping and embracing, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Chimpanzee (Pan troglodytes) adult male standing upright, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Bonobo (Pan paniscus) knuckle-walking through grass, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Chimpanzee (Pan troglodytes) playing with burlap sack, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Chimpanzee (Pan troglodytes) playing with burlap sack, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Chimpanzee (Pan troglodytes), La Vallee Des Singes Primate Center, France

Cyril Ruoso / Bonobo (Pan paniscus) knuckle-walking through grass, native to Africa

Cyril Ruoso / Chimpanzee (Pan troglodytes) pair vocalizing, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Chimpanzee (Pan troglodytes) using a stick to get milk and meat out of a coconut, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Bonobo (Pan paniscus) portrait, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Chimpanzee (Pan troglodytes) portrait, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Bonobo (Pan paniscus) young male sitting on fallen tree, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Chimpanzee (Pan troglodytes) young male playing with a twig, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Chimpanzee (Pan troglodytes) young male sitting on fallen tree, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Chimpanzee (Pan troglodytes) pair knuckle-walking, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Chimpanzee (Pan troglodytes) portrait, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Chimpanzee (Pan troglodytes) adult yawning, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Chimpanzee (Pan troglodytes) pair eating fruit, photographed at the La Vallee des Singes primate center in France

Cyril Ruoso / Bonobo (Pan paniscus) young male sitting on fallen tree, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Bonobo (Pan paniscus) sitting on fallen tree, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Chimpanzee (Pan troglodytes) portrait, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Chimpanzee (Pan troglodytes) male eating fruit as he walks bipedally, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Chimpanzee (Pan troglodytes) running across grassy field, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Bonobo (Pan paniscus) playing with stick, La Vallee Des Singes Primate Center, France

Cyril Ruoso / Chimpanzee (Pan troglodytes) putting on a show for spectators, at La Vallee Des Singes Primate Center, France