Gerry Ellis / De Brazza's Monkey (Cercopithecus neglectus) portrait, captive animal, Woodland Park Zoo, Washington

Gerry Ellis / Solomon Island Leaf Frog (Ceratobatrachus guentheri), Woodland Park Zoo, Washington

Gerry Ellis / Chimpanzee (Pan troglodytes) uses fishing tool to catch insects, Washington Park Zoo, Washington

Gerry Ellis / Chimpanzee (Pan troglodytes) teaching, young male to use fishing tool, Washington Park Zoo

Gerry Ellis / Jaguar (Panthera onca) portrait of young Jaguar, Woodland Park Zoo, Washington

Gerry Ellis / Jaguar (Panthera onca) fur, close-up of patterned detail, Washington Park Zoo, Portland, Oregon

Gerry Ellis / Chimpanzee (Pan troglodytes) uses fishing tool, Washington Park Zoo

Gerry Ellis / Chimpanzee (Pan troglodytes) uses fishing tool to feed on insects, Washington Park Zoo

Gerry Ellis / Ring-tailed Lemur (Lemur catta) group, Washington Park Zoo, Portland, Oregon, endemic to Madagascar

Gerry Ellis / Jaguar (Panthera onca) skin

Gerry Ellis / African Lion (Panthera leo) male, portrait, Washington Park Zoo, Portland, Oregon

Gerry Ellis / African Lion (Panthera leo) male, Washington Park Zoo, Portland, Oregon

Gerry Ellis / Chimpanzee (Pan troglodytes) teaching young male to use fishing tool, Washington Park Zoo

Gerry Ellis / Snow Leopard (Uncia uncia) pelt, Woodland Park Zoo, Washington

Gerry Ellis / Gray Mouse Lemur (Microcebus murinus) eating, Woodland Park Zoo, Seattle, Washington

Michael Hutchinson / Batang (female Bornean orang-utan on the left) and Bonnie (hybrid Bornean-Sumatran on the right) watched by visitors, Washington National Zoological Park, USA

Gerry Ellis / Reticulated Giraffe (Giraffa reticulata) portrait, Woodland Park Zoo, Seattle, Washington

Gerry Ellis / Western Lowland Gorilla (Gorilla gorilla gorilla) female, Woodland Park Zoo, Seattle, Washington

Gerry Ellis / Western Lowland Gorilla (Gorilla gorilla gorilla) female with baby, Woodland Park Zoo, Seattle, Washington

Gerry Ellis / Patas Monkey (Erythrocebus patas) portrait, Woodland Park Zoo, native to central Africa

Gerry Ellis / Solomon Island Leaf Frog (Ceratobatrachus guentheri) egg sac, Woodland Park Zoo, Washington

Gerry Ellis / Jaguar (Panthera onca) fur, close-up of patterned detail, Washington Park Zoo, Portland, Oregon

Gerry Ellis / Chimpanzee (Pan troglodytes) uses fishing tool to catch insects, Washington Park Zoo

Gerry Ellis / Ring-tailed Lemur (Lemur catta) calling, Woodland Park Zoo, Seattle, Washington, endemic to South Madagascar

Gerry Ellis / Siamang (Hylobates syndactylus) portrait, Woodland Park Zoo, Seattle, Washington

Gerry Ellis / Snow Leopard (Uncia uncia), Woodland Park Zoo, Seattle, Washington

Gerry Ellis / Solomon Island Leaf Frog (Ceratobatrachus guentheri), Woodland Park Zoo, Washington

Gerry Ellis / Western Lowland Gorilla (Gorilla gorilla gorilla) young male, Woodland Park Zoo, Seattle, Washington

Gerry Ellis / Jaguar (Panthera onca) panting, Woodland Park Zoo, Seattle, Washington

Gerry Ellis / Lion-tailed Macaque (Macaca silenus) pair sitting together on grass, Woodland Park Zoo, Seattle, Washington

Gerry Ellis / Western Lowland Gorilla (Gorilla gorilla gorilla) young male, Woodland Park Zoo, Seattle, Washington

Gerry Ellis / Bengal Tiger (Panthera tigris tigris) portrait, at Woodland Park Zoo, Seattle, Washington, native to India and southeast Asia

Gerry Ellis / Green Tree Python (Chondropython viridis) portrait, Woodland Park Zoo, native to Papua New Guinea

Gerry Ellis / Green Tree Python (Chondropython viridis) juvenile portrait, native to New Guinea, Woodland Park Zoo, Seattle, Washington

Gerry Ellis / Sun Bear (Helarctos malayanus) portrait, Woodland Park Zoo, Washington

Gerry Ellis / Snow Leopard (Uncia uncia) portrait, Woodland Park Zoo, Seattle, Washington

Gerry Ellis / Snow Leopard (Uncia uncia) skin showing spotted pattern, native to Asia

Gerry Ellis / Snow Leopard (Uncia uncia), Woodland Park Zoo, Seattle, Washington

Gerry Ellis / African Lion (Panthera leo) portrait of male yawning, Washington Park Zoo, Portland, Oregon

Gerry Ellis / Chimpanzee (Pan troglodytes) male portrait, Washington Park Zoo