Mary McDonald / Black striped capuchin (Sapajus libidinosus) using rocks to crack nuts, Piaui, Brazil

Mary McDonald / Black striped capuchin (Sapajus libidinosus) using rocks to crack nuts, with young animal watching and learning, Piaui, Brazil

Mary McDonald / Black striped capuchin (Sapajus libidinosus) using rocks to crack nuts, Piaui, Brazil

Mary McDonald / Black striped capuchin (Sapajus libidinosus) using rock to crack nuts, Piaui, Brazil

Mary McDonald / Brown Capuchin (Cebus apella) using rocks to crack nuts, Piaui, Brazil

Anup Shah / Chimpanzee {Pan troglodytes} using tool to extract and feed on insects in tree trunk, Tanzania

Anup Shah / Young Chimpanzees + mother fishing for termites, Gombe NP, Tanzania 2003 'Gremlin'

Anup Shah / Male Chimpanzee + young fishing for termites, Gombe NP, Tanzania 2003 'Gremlin'

Karl Ammann / Young Chimpanzees using grass stems to extract termites from mound {Pan troglodytes} in sanctuary, Kenya

Miles Barton / Japanese Macaque {Macaca fuscata} washing sweet potato in water. Koshima Island, Japan

Karl Ammann / Chimpanzee cracks nut with stone. Sanctuary, Kenya

Anup Shah / Chimpanzee baby watching adult playing with twig