Pigeon In Skinner Box
Photo Researchers, Inc.
Monkey Research
Photo Researchers, Inc.
American Kestrel
Scott Linstead
Icelandic Horses
John Daniels
Gray Wolf And Cubs #3
Jean-Louis Klein & Marie-Luce Hubert
Miniature Donkeys #1
Jean-Louis Klein & Marie-Luce Hubert
Miniature Donkey Foal
Jean-Louis Klein & Marie-Luce Hubert
Brindle Boxer Pup #1
Jane Burton
Piglets Playing In Snow #1
Jean-Louis Klein & Marie-Luce Hubert
Great White Shark #5
Jean-Louis Klein & Marie-Luce Hubert
Iguanodon Biting Megalosaurus #1
Wellcome Images
Miniature Donkey Foal #1
Jean-Louis Klein & Marie-Luce Hubert
Praying Mantis #10
Perennou Nuridsany
Great Crested Grebes
Des Ong FLPA
Gentoo Penguins Bonding
Gregory G. Dimijian
Emperor Penguins And Chicks
Jean-Louis Klein & Marie-Luce Hubert
Olive Ridley Turtles
M. Watson
White-tailed Sea Eagle
Thomas Hanahoe
Catfish Protecting Her Young #2
Ted Kinsman
Black-tailed Prairie Dog Family At Den
Ivan Kuzmin
Rough Collie #2
Jean-Michel Labat
Snow Monkey And Young
Jean-Louis Klein & Marie-Luce Hubert
Polar Bear With Cub #7
M Watson
Wild Horses Mating
Michael Lustbader
Common Loon Gavia Immer, Canada #36
John Shaw
Polar Bear With Cub
M. Watson
Wolf Social Behavior #2
Jean-Louis Klein & Marie-Luce Hubert
Wolf Social Behavior
Jean-Louis Klein & Marie-Luce Hubert
Western Gorilla And Young
Jurgen & Christine Sohns/FLPA
Wistar Rat
Science Source
Miniature Donkey Foal #5
Jean-Louis Klein & Marie-Luce Hubert
Elk Bugling At Sunset
Kenneth W Fink
Royal Terns #1
Paul J. Fusco
Jaguars #3
Millard H. Sharp
Lion And Lioness Mating
Greg Dimijian
Black Bear With Salmon
Ron Sanford
Gray Wolves Playing
Jean-Louis Klein & Marie-Luce Hubert
Great White Shark #8
Jean-Louis Klein & Marie-Luce Hubert
Emperor Dragonfly
M. Watson
Marsh Wren
Richard Hansen
Olympic Marmot
Thomas And Pat Leeson
Harlows Monkey Experiment
Photo Researchers, Inc.
Antilles Pinktoe Tarantula
Dante Fenolio
Greater Roadrunner #11
Scott Linstead
Red-crowned Cranes Courting
John Shaw
Abyssinian Kitten In Dance Studio
Joan Baron
Frill-necked Lizard
BG Thomson
Bulldog With Flowers
John Daniels
Wire Fox Terrier #2
John Daniels
Mustang Stallion
Jean-Louis Klein & Marie-Luce Hubert
Polar Bear And Cubs #1
Jean-Louis Klein and Marie-Luce Hubert
Young Mustangs Playing #2
Jean-Louis Klein & Marie-Luce Hubert
Fighting European Hares
Manfred Danegger
Naughty Ladies 19th Century
Science Source
Orinoco Crocodile Protecting Nest
M. Watson
Green Anacondas
M. Watson
Brown Rat With Young
Jean-Michel Labat
Eastern Box Turtle #3
Millard H. Sharp
Sanderlings
Anthony Mercieca
Common Loon Gavia Immer, Canada #9
John Shaw
Common Loon Gavia Immer, Canada #14
John Shaw
Common Loon Gavia Immer, Canada #25
John Shaw
Common Loon Gavia Immer, Canada #39
John Shaw
Andean Emerald Hummingbirds
John Shaw
Gannet Birds Showing Meeting Behavior
Ted Kinsman
Blue-footed Courtship Behavior
William H. Mullins
Behavior Of A Shadow
Science Source
False Clownfish
Franco Banfi and Photo Researchers
Royal Terns
Paul J. Fusco
Mental Illness
George Mattei