Alexander Badyaev / Deer mouse (Peromyscus maniculatus) on giant puffball mushroom, watching mosquito in the moonlight. Blackfoot Valley, Western Montana, USA, July. Winner of the Mammals category, Wildlife Photographer...

George Sanker / Anhinga (Anhinga anhinga) with large Bluegill Sunfish (Lepomis macrochirus) prey, Everglades National Park, Florida, USA, March.

Ingo Arndt / Sea Otters (Enhydra lutris) one with pup, on ice floe, Prince William Sound, Alaska, USA. June.

Ingo Arndt / Sea Otter (Enhydra lutris) group raft, floating on their backs, Prince William Sound, Alaska, USA. June.

Ingo Arndt / Grand Prismatic Spring, Midway Geyser Basin, Yellowstone National Park, Wyoming, USA, September 2011

George Sanker / White-tailed deer (Odocoileus virginianus) in snow, Acadia National Park, Maine, USA, February.

George Sanker / Mallard (Anas platyrhynchos) walking on ice, Acadia National Park, Maine, USA, April.

Thomas Lazar / Water rushing down alpine stream, Logan Pass, Glacier National Park, Rocky Mountains, Montana, July 2010.

Thomas Lazar / Hikers on frozen lake looking at sea caves and ice formations, Apostle Islands National Lakeshore, Lake Superior, Squaw Bay, Wisconsin, February 2014.

Thomas Lazar / Icicles hanging from sandstone cliffs on shoreline, Apostle Islands National Lakeshore, Lake Superior, Squaw Bay, Wisconsin, February 2014.

Thomas Lazar / Jagged icicles hanging from towering sandstone cliff, Apostle Islands National Lakeshore, Lake Superior, Squaw Bay, Wisconsin, February 2014.

Carol Walker / Chestnut Mustang running in snow, at ranch, Shell, Wyoming, USA. February.

Carol Walker / Wild Mustang pinto foal nuzzling up to mother, Sand Wash Basin Herd Area, Colorado, USA.

Inaki Relanzon / Photographer taking photos of rock formations, silhouetted at sunset on the Pacific coast of Olympic National Park, Washington State, USA. Model released.

Carol Walker / Wild Mustang foals among wild flowers, Pryor Mountains, Montana, USA.

Carol Walker / Skewbald Horse in ranch, Martinsdale, Montana, USA.

Inaki Relanzon / Rock formations silhouetted at sunset on the Pacfic coast of Olympic National Park, Washington State, USA.

Steven Kazlowski / Woman hiker with tired puppy in a backpack, Mount Townsend, northwest Olympic National Park, Olympic Peninsula, Washington, USA. November 2013. Model released.

Oliver Scholey / Grizzly bear (Ursus arctos horribilis) with Grey wolf (Canis lupus) stretching behind, Katmai National Park, Alaska, USA, August.

Oliver Scholey / Grey wolf (Canis lupus) portrait, Katmai National Park, Alaska, USA, August.

Juan Carlos Munoz / Great Basin Bristlecone Pine (Pinus longaeva) trunk of ancient tree, Inyo National forest, White Mountains, California, USA.

Juan Carlos Munoz / Great Basin Bristlecone Pine (Pinus longaeva) fallen ancient tree, White Mountains, California, USA, March.

Kirkendall-Spring / Rock climber on a route called 'Any Major Dude' along the Ledge Spring Trail in Pilot Mountain State Park. North Carolina, USA, October 2013. Model released.

Doug Wechsler / Peregrine Falcon (Falco peregrinus) perched on City Hall, Philadelphia, Pennsylvania, USA, May.

David Tipling / California Condor (Gymnogyps californianus) portrait, wild, Arizona, USA, April.

Mary McDonald / Pika (Ochotona princeps) in scree rock pile, Sheepeaters Cliff, Yellowstone National Park, Wyoming, USA, September.

Peter Cairns / Calcified trees at Tangled Creek in winter, Yellowstone National Park, Wyoming, USA, February 2013.

Juan Carlos Munoz / Bald eagle (Haliaeetus leucocephalus) in flight, silhouetted at sunset, Haines, Alaska, March.

George Sanker / American Red fox (Vulpes vulpes fulva) baby playing with mother, Grand Teton National Park, Wyoming, USA, May.

George Sanker / American Red fox (Vulpes vulpes fulva) baby leaping on its disinterested mother. Grand Teton National Park, Wyoming, USA, May.

George Sanker / American Red fox (Vulpes vulpes fulva) mother and two cubs playing, Grand Teton National Park, Wyoming, USA, May.

MYN / Seth Patterson / Red-eared Slider (Trachemys scripta elegans) juvenile viewed from above, Sabal Palm Sanctuary, Cameron County, Lower Rio Grande Valley, Texas, United States of America, North America, September. Meety...

MYN / Seth Patterson / Red-eared Slider (Trachemys scripta elegans) juvenile portrait, Sabal Palm Sanctuary, Cameron County, Lower Rio Grande Valley, Texas, United States of America, North America, September. Meetyourneighb...

Jouan Rius / Silhouettte of Joshua tree (Yucca brevifolia) at sunset, Joshua Tree National Park, Mojave Desert, California, USA, January 2013.

Jouan Rius / Irregular ripples on gypsum sand dunes created by high winds, White Sands National Park, Chihuahuan Desert, New Mexico, USA, December 2012.

Jouan Rius / Trunks of giant sequoia trees (Sequoiadendron giganteum) Sequoia National Park, California, USA, November 2012.

Floris van Breugel / Warm sunlight in waterfall paradise, in Gifford Pinchot National Forest. Washington, USA, May 2013

Jack Dykinga / White Sands National Park with its white gypsum dunes dotted with Yuccas (Yucca elata) creating patterns amid the dunes. White Sands, New Mexico, USA. January 2013

Jouan Rius / Sandstone formations in Goblin Valley State Park, Utah, USA November 2012

Jouan Rius / Sandstone cliff at sunset, Colorado Plateau, Kodachrome Basin State Park, Utah, USA November 2012

Steven Kazlowski / Polar bear (Ursus maritimus) juvenile spreading body weight over thin newly forming pack ice, trying not to break through, Beaufort Sea, off the 1002 area of the Arctic National Wildlife Refuge, North...

Steven Kazlowski / Polar bear (Ursus maritimus) curious subadult along a barrier island in autumn, Beaufort Sea, off the 1002 area of the Arctic National Wildlife Refuge, North Slope, Alaska

Doug Perrine / Male Hawaiian monk seal (Monachus schauinslandi) at Lehua Ledges dive site, Lehua Rock, near Niihau, off Kauai, Hawaii

David Tipling / Great Blue Heron (Ardea herodias) shaking water off feathers, Florida Everglades

Benjamin Barthelemy / Female Pintail (Anas acuta) with chicks, Katmai National Park and Preserve, Alaska, USA, July.

Doug Perrine / Green sea turtle (Chelonia mydas) being cleaned by yellow tangs (Zebrasoma flavescens) at a cleaning station where the turtles are groomed by the fish in a mutualistic, symbiotic relationship, Puako,...

David Tipling / Snow Geese (Chen caerulescens) taking off at dawn Bosque del Apache, New Mexico, USA, winter

George Sanker / American Purple Gallinule (Porphyrio martinica) displaying brightly coloured wings. Everglades National Park, Florida, USA, March.

George Sanker / American Red Fox (Vulpes vulpes) cubs playing with its mother. Grand Teton National Park, USA, June.

George Sanker / American Black Bear (Ursus americanus) cub. Yellowstone National Park, Wyoming, June.

Jeff Vanuga / Balancing Rock with moon and Venus. Arches National Park, Utah, November 2010.

John Cancalosi / Raccoon (Procyon lotor) in tree hole, New York, USA

Nick Garbutt / Male Coyote (Canis latrans) walking through deep snow. Hayden Valley, Yellowstone National Park, Wyoming, USA, February.

Doc White / Blue Whale (Balaenoptera musculus) feeding at sea surface, releasing bubbles after a lunge. California, USA.

Danny Green / Wolves (Canis lupus) sitting on a hillside in snow. Yellowstone, USA, February.

Floris van Breugel / Canyon Tree Frogs (Hyla arenicolor) near pond along the lower reaches of Pine Creek, Zion National Park, Utah, USA, June

Floris van Breugel / Late afternoon sunshine streams through green Valley Oaks (Quercus lobata Nee) Shell Ridge at the base of Mount Diablo, California, USA. April

Floris van Breugel / Calm seas of the Pacific Ocean at twilight, along the wilderness coast of Shi Shi beach at low tide, Olympic National Park, Washington, USA, March 2012.

Floris van Breugel / Enchantment Lakes in early winter snow with Larch trees bearing autumn leaves, Alpine Lakes Wilderness, Central Cascade range, Washington, USA, November 2011.

Floris van Breugel / Waterfall seen through a window of fresh spring growth in Columbia River Gorge, Oregon, USA. May

Floris van Breugel / Natural iridescent plant oils from decaying leaves at the surface of a pool, Escalante National Monument, Utah. November

Floris van Breugel / Aspen leaves on an early snow, North Fork of Bishop Creek, near Bishop, Eastern Sierra, California, USA, October.

Floris van Breugel / Darkling Beetle (Tenebrionidae) on sand in White Sands National Park, New Mexico, USA, April.

Floris van Breugel / Wind and blowing sand has, over millions of years, carved incredible forms out of the Southwest's sandstone, such as this alcove and double arch. Vermilion Cliffs, Arizona, USA

Floris van Breugel / Anna's Hummingbird (Calypte anna) stretching, Mount Diablo State Park, California, USA, March