An ice-covered bison in an autumn snow storm in Yellowstoen National Park.
An elk cow on a snowy morning near Lake Minnewanka in Banff National Park in Alberta,Canada.
A black-legged kittiwake in flight
A wet baby African elephant sucks her trunk as she follows her mother after a bath in the Ewaso Ng'iro River in Samburu in Kenya.
Spectacled Caiman 091203_490
A spectacled caiman on the Cano Negro River in Costa Rica.
A basilisk lizard perches on a branch in the Rio Frio River in northern Costa Rica. If he spots an insect like a butterfly he will run across the top of the water to catch it, giving him the nickname "The JesusChrist Lizard".
Black-crowned Night-Heron_Immature 091203_281
An immature black-crowned night-heron perched on a tree buttress above the Rio Frio River in Cano Negro in Costa Rica in December.
Great Horned Owl
A great Horned owl in a cottonwood tree at Malheur National Wildlife Refuge in southeastern Oregon in autumn.
Osprey Nest 080413_138
An osprey hovers briefly above its nest with grasses in it talons as his matewaits to help with the remodelling. Photographed at Snag Boat Bend National Wildlife Refuge in Oregon.
Green Violet-ear Hummingbird
A green violet-ear hummingbird sticking his tongue out while perched on a branch at Savegre in the Tallamanca Mountains of southern Costa Rica.
Howler Monkey 091202_852
A young howler monkey eating a vine in the rain forest of Costa Rica.
Sleeping Polar Bear
A polar bear naps on an ice floe in the arctic in Svalbard, north of Norway.
Polar Bear and Glaucous Gull 080712_176
This polar bear was in a never-ending battle with the glaucous gulls at a seal carcass on an ice floe in the arctic region of Svalbard north of Norway in July.
Denali Caribou on fall tundra HER001y
A young bull caribou (Rangifer tarandus) is surrounded by spectacular fall colors of the Alaskan tundra in early September in Denali National Park.
Newborn African Elephant 100919_146
A wild newborn elephant walks in the shelter of his mother and aunts at Samburu in Kenya.
Rocky Mountain Elk HER019f
A bull elk feeds on a hill side just under the low cloud cover over a canyon in Wyoming in autumn.
Facial detail of a young Atlantic walrus in Spitsbergen. The whiskers are extremely sensitive and are used to detect food as he forages through the mud of the sea floor.
Female Cheetah with Cub 070918_013
A female cheetah snuggles with her cub as the sun is setting on the Masai Mara Preserve in Kenya.
Apres l'Amour 100905_548
Mating lion pair in the Masa Mara in Kenya.
African Elephant 100911_929
An African elephant portrait from the Masai Mara in Kenya.
Violet-headed Hummingbird 091207_105
A violet-headed hummingbird perched on a limb in in the mountains of southern Costa Rica.
American Bison 080927_029
An American bison standing in a field of tall grass.
A female leopard in Samburu in Kenya.