Daniel Heuclin / Cottontop cactus (Echinocactus polycephalus) Death Valley National Park, California, USA, August

Daniel Heuclin / Cottontop cactus (Echinocactus polycephalus) Death Valley National Park, California, USA, August

Rod Williams / Cotton-top Tamarin (Saguinus oedipus) portrait sitting in tree. Captive, found in NW Colombia. Critically Endangered.

Rod Williams / Cotton-top Tamarin (Saguinus oedipus) portrait of juvenile, sitting in tree. Captive, found in NW Colombia. Critically Endangered.

Lisa Hoffner / Wild Cotton-top tamarin (Saguinus oedipus) appears to fly through the air as it jumps from branch to branch in the dry tropical forest of Colombia, South America IUCN List: Critically Endangered

Lisa Hoffner / Wild Cotton-top Tamarin (Saguinus Oedipus) stretchng on tree trunk, in tropical dry forest of Colombia, South America. IUCN List: Critically Endangered

Lisa Hoffner / Wild Cotton-top Tamarin (Saguinus Oedipus) with very young baby on its back, resting on vine in tropical dry forest of Colombia, South America. IUCN List: Critically Endangered

Lisa Hoffner / Three wild Cotton-top tamarins (Saguinus oedipus) climbing up branches in the dry tropical forest of Colombia, South America. IUCN List: Critically Endangered

Lisa Hoffner / Wild Cotton-top tamarin (Saguinus oedipus) clings to a branch after rainstorm in the dry tropical forest of Colombia, South America. IUCN List: Critically Endangered

Lisa Hoffner / Wild Cotton-top tamarin (Saguinus oedipus) carrying a baby on its back in the dry tropical forest of Colombia, South America. IUCN List: Critically Endangered

Lisa Hoffner / Wild Cotton-top tamarin (Saguinus oedipus) male carrying a baby on his back in the dry tropical forest of Colombia, South America. IUCN List: Critically Endangered

Lisa Hoffner / Biologist Luis Soto inspects a caterpillar on end of stick. These are a food source for the Cotton-top Tamarins (Saguinus Oedipus) Colombia, South America. July 2008