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
Naughty Ladies 19th Century
Science Source
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
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