Jack Dykinga / Scalding hot water continuously spouting behind layers of mineral deposits, Fly Geyser, Black Rock Desert, Great Basin Desert, Nevada, USA

Steven Kazlowski / Young Polar bear (Ursus maritimus) standing and trying to balance in shallow water along the Bernard Spit, 1002 area of the Arctic National Wildlife Refuge, North Slope of the Brooks Range, Alaska, Oc...

Steven Kazlowski / Young Polar bear (Ursus maritimus) standing and trying to balance in shallow water along the Bernard Spit, 1002 area of the Arctic National Wildlife Refuge, North Slope of the Brooks Range, Alaska, Oc...

Steven Kazlowski / Young Polar bear (Ursus maritimus) standing and trying to balance in shallow water along the Bernard Spit, 1002 area of the Arctic National Wildlife Refuge, North Slope of the Brooks Range, Alaska, Oc...

Steven Kazlowski / Two curious young Polar bears (Ursus maritimus), Barter Island, off the 1002 area of the Arctic National Wildlife Refuge, North Slope of the Brooks Range, Alaska, October 2011

George Sanker / Ellis River high in White Mountain National Forest. New Hampshire, October 2012.

George Sanker / American Buffalo / Bison (Bison bison) grazing in open plains. Yellowstone National Park, Wyoming, October.

Piotr Naskrecki / Mantid (Mantidae), Woburn, Massachusetts

Piotr Naskrecki / Mantid (Taumantis sp) instar, Woburn, Massachusetts

Gavin Hellier / Elevated view of mid-town Manhattan, New York City, USA 2009. No release available.

Gavin Hellier / Panoramic view of Queensboro Bridge and Mid town Manhattan, New York City, USA 2009. No release available.

Gavin Hellier / Typical yellow taxis below skyscrapers along Sixth Avenue, Manhattan, New York City, USA, 2009. No release available.

Gavin Hellier / Looking up at the Empire State Building on a rainy evening, Manhattan, New York City, USA 2009. No release available.

Gavin Hellier / Panoramic view of the foggy skyline of San Francisco at sunrise, California, USA 2011

Gavin Hellier / Wenkchemna Peaks or Ten Peaks rising over Moraine lake in the snow, near Lake Louise, Banff National Park, Alberta, Canada, 2007

Gavin Hellier / Wenkchemna Peaks or Ten Peaks rising over Moraine lake in the snow, near Lake Louise, Banff National Park, Alberta, Canada, 2007

Gavin Hellier / Peyto Lake, coloured by glacial silt, Banff-Jasper National Parks, Alberta, Canada, 2007

Gavin Hellier / Skyline and inner harbour including Rowes Wharf at dawn, Boston, Massachusetts, USA 2009. No release available.

Gavin Hellier / View of downtown Los Angeles, California, USA, July 2011. No release available.

Gavin Hellier / Luxury cruise liner infront of Midtown Manhattan across the Hudson River, New York, USA October 2011. No release available.

Jeff Vanuga / Aerial view of Grand Prismatic Springs Midway Geyser Basin. Yellowstone National Park, Wyoming, July 2011.

Michel Roggo / Sockeye / Red Salmon (Oncorhynchus nerka) on spawning migration; males surrounding a female. Adams River, British Columbia, Canada, October.

Michel Roggo / Sockeye / Red Salmon (Oncorhynchus nerka) on spawning migration. Adams River, British Columbia, Canada, October.

Michel Roggo / Sockeye / Red Salmon (Oncorhynchus nerka) on spawning migration. Adams River, British Columbia, Canada, October.

Michel Roggo / Sockeye / Red Salmon (Oncorhynchus nerka) on spawning migration. Adams River, British Columbia, Canada, October.

Michel Roggo / Sockeye / Red Salmon (Oncorhynchus nerka) on spawning migration. Adams River, British Columbia, Canada, October.

Michel Roggo / Atlantic Salmon (Salmo salar) in pool on upstream spawning migration. Quebec, Canada, August.

Tim Fitzharris / Grizzly Bear (Ursus arctos horribilis) cub in snow, Idaho

Tim Fitzharris / Ruby Beach, Olympic National Park, Washington

Doc White / Blue Whales (Balaenoptera musculus) throat inflated, filter feeding at sea surface. California, USA. Sequence 1 of 2.

Danny Green / Snow Geese (Chen caerulescens) in flight, silhouetted against colourful dusk sky. Bosque del Apache, New Mexico, USA, November.

Danny Green / Snow Goose (Chen caerulescens), coming in to land. Bosque del Apache, New Mexico, USA, November.

Alex Mustard / Two Whale sharks (Rhincodon typus) feeding on fish eggs at the surface, Isla Mujeres, Quintana Roo, Yucatan Peninsula, Mexico, Caribbean Sea.

Sumio Harada / Black Bear (Ursus americanus) mother and cub near tree den, Glacier National Park, Montana

Ingo Arndt / Grizzly Bear (Ursus arctos horribilis) front and rear tracks in mud, Lake Clark National Park, Alaska

Ingo Arndt / Timber Wolf (Canis lupus) running in snow, Minnesota

Ingo Arndt / Grizzly Bear (Ursus arctos horribilis) chasing salmon, Lake Clark National Park, Alaska

Ingo Arndt / Grizzly Bear (Ursus arctos horribilis) cub running through shallow water, Lake Clark National Park, Alaska

Ingo Arndt / Grizzly Bear (Ursus arctos horribilis) mother with cub, Lake Clark National Park, Alaska

Ingo Arndt / Timber Wolf (Canis lupus) crossing river, Minnesota

Marie Read / Pinyon Jay (Gymnorhinus cyanocephalus), gathering Pinyon Pine seeds in autumn. Mono Lake Basin, California, USA, October.

Jeff Rotman / Northern Sea Stars (Asterias vulgaris) feeds on bed of mussels. Cathedral Rocks, Gloucester, Massachusetts, New England USA - North Atlantic Ocean.

Mark Carwardine / Whale shark (Rhincodon typus) aerial view of juvenile with two people swimming alongside, La Paz Bay, Sea of Cortez (Gulf of California), Baja California, Mexico, March 2009

Mark Carwardine / Hands of a tourist leaning from boat to touch the mouth of a friendly Grey whale (Eschrichtius robustus) lying on the surface, San Ignacio Lagoon, Baja California, Mexico, April 2009

Mark Carwardine / Grey whale (Eschrichtius robustus) underwater, San Ignacio Lagoon, Baja California, Mexico

Mark Carwardine / Split-level of tourist in small boat leaning out to touch a Grey whale (Eschrichtius robustus) San Ignacio Lagoon, Baja California, Mexico, April 2009

Mark Carwardine / Tourists watching Grey whale (Eschrichtius robustus) spyhopping, San Ignacio Lagoon, Baja California, Mexico, February 2010

Mark Carwardine / Grey whale (Eschrichtius robustus) spyhopping, San Ignacio Lagoon, Baja California, Mexico

Mark Carwardine / Whale shark (Rhincodon typus) aerial view of juvenile with two people swimming alongside, La Paz Bay, Sea of Cortez (Gulf of California), Baja California, Mexico, March 2009

Mark Carwardine / Tourists in small boat leaning out to touch a curious Grey whale (Eschrichtius robustus) San Ignacio Lagoon, Baja California, Mexico, March 2007

Mark Carwardine / Tourists in small boat watching curious Grey whale (Eschrichtius robustus) spyhopping, San Ignacio Lagoon, Baja California, Mexico, February 2007

Mark Carwardine / Grey whale (Eschrichtius robustus) close-up of eye, San Ignacio Lagoon, Baja California, Mexico

Mark Carwardine / Two Humpback whales (Megaptera novaeangliae) bubble-net feeding very close to shore, Great Bear Rainforest, British Columbia, Canada, Endangered or threatened species (Vulnerable)

Mark Carwardine / Humpback whales (Megaptera novaeangliae) feeding on herring, showing palate and baleen plates, Frederick Sound, South East Alaska, USA, Endangered or threatened species (Vulnerable)

Mark Carwardine / Two Sandhill cranes (Grus canadensis) flying, Bosque del Apache National Wildlife Refuge, New Mexico, USA

Mark Carwardine / Mallard (Anas platyrhynchos) drake flying, Bosque del Apache National Wildlife Refuge, New Mexico, USA

Mark Carwardine / Adult male Northern pintail duck (Anas acuta) flying, Bosque del Apache National Wildlife Refuge, New Mexico, USA

Mark Carwardine / Sandhill cranes (Grus canadensis) flying, Bosque del Apache National Wildlife Refuge, New Mexico, USA

Mark Carwardine / Blue whale (Balaenoptera musculus) blowing, Baja California, Sea of Cortez (Gulf of California), Mexico, Endangered species

Mark Carwardine / Grey whale calf (Eschrichtius robustus), San Ignacio Lagoon, Baja California, Mexico

Mark Carwardine / Blue whale (Balaenoptera musculus) fluking, Baja California, Sea of Cortez (Gulf of California), Mexico, Endangered species

Mark Carwardine / Grey whale (Eschrichtius robustus) calf upside down, San Ignacio Lagoon, Baja California, Mexico

Mark Carwardine / Blue whale (Balaenoptera musculus) fluking, Baja California, Sea of Cortez (Gulf of California), Mexico, Endangered species

Mark Carwardine / California sealions (Zalophus californianus), one in water with other sitting on rock, Baja California, Sea of Cortez (Gulf of California), Mexico

Mark Carwardine / Grey whale (Eschrichtius robustus), San Ignacio Lagoon, Baja California, Mexico

Mark Carwardine / Common bottlenose dolphin (Tursiops truncatus) swimming fast, Baja California, Sea of Cortez (Gulf of California), Mexico

Mark Carwardine / Ocean sunfish (Mola mola) near surface, Baja California, Sea of Cortez (Gulf of California), Mexico

Mark Carwardine / Long-beaked common dolphin (Delphinus capensis) porpoising swimming fast, Baja California, Sea of Cortez (Gulf of California), Mexico

Mark Carwardine / Common bottlenose dolphin (Tursiops truncatus) surfacing, Baja California, Sea of Cortez (Gulf of California), Mexico

Mark Carwardine / Common bottlenose dolphin (Tursiops truncatus) surfacing, Baja California, Sea of Cortez (Gulf of California), Mexico

Mark Carwardine / Smoothtail Ray / Mobula (Mobula thurstoni) flying out of the water, Baja California, Sea of Cortez (Gulf of California), Mexico

Mark Carwardine / Pacific white-sided dolphin / Lag (Lagenorhynchus obliquidens) swimming fast, showing dorsal fin, Johnstone Strait, Vancouver Island, British Columbia, western Canada

Mark Carwardine / Aerial view of adult female Blue whale (Balaenoptera musculus), Sea of Cortez (Gulf of California), Baja California, Mexico (Pacific coast), Endangered species

Mark Carwardine / Black bear (Ursus americanus) catching salmon, Princess Royal Island, the Great Bear Rainforest, British Columbia, western Canada

Mark Carwardine / Watching Killer whale underwater in aquarium {Orcinus orca} USA

Floris van Breugel / Autumn colors along the shores of Pharaoh Lake in Adirondacks park, New York, USA. October

Floris van Breugel / Winter snowstorm with frost covered trees , Hurricane Ridge, Olympic National Park, Washington, USA, February 2012.

Floris van Breugel / Sub-alpine larches (Latrix sp.) in late autumn in North Cascades National Park, Washington, USA. October.

Floris van Breugel / Reflected light on various sandstone surfaces in a narrow slot canyon in Arizona, USA, June

Floris van Breugel / A skier glides past an erupting geyser in the Old Faithful geyser basin in Yellowstone National Park. The cold temperatures in the winter cause the geysers to release more steam than usual making the...

Floris van Breugel / Natural iridescent oil film from decaying leaves at the surface of a pool, with a cottonwood leaf floating. Escalante National Monument, Utah. November.

Floris van Breugel / Hoar frost coats the edges of ferns in a clearing in Washington's Olympic National Park, USA. December.

Jack Dykinga / Bark patterns of Aspen tree (Populus tremula) in front of a Ponderosa pine (Pinus ponderosa) trunk, Kaibab National Forest, Arizona, USA

Jack Dykinga / Sunflower flower (Helianthus petiolaris) at Sunset Crater National Monument, Arizona

Oriol Alamany / Angel Glacier with morraine, Jasper National Park, Rocky Mountains, Alberta, Canada

Oriol Alamany / Nigel Creek with conifer forest at dusk, Banff National Park, Rocky Mountains, Alberta, Canada

Martha Holmes / Burrowing owl (Athene cunicularia) living in a wrecked helicopter fuselage. Florida, USA. August 2008.

Steven Kazlowski / North American porcupine (Erethizon dorsatum) pup feeds on Alaskan high brush cranberries in the foothills of the Takshanuk Mountains, South-East Alaska, USA

Steven Kazlowski / Spirit bear (Ursus americanus) sow with dark cub walking on a log at high tide, along the coastal rainforest of the central British Columbia coast, Canada

Steven Kazlowski / Polar bear (Ursus maritimus) adult walking over newly formed pack ice during fall freeze up, 1002 area of the Arctic National Wildlife Refuge, North Slope, Alaska, USA

Steven Kazlowski / Killer whale (Orcinus orca) large pod with one male approaching, in Kenai Fjords National Park, Chiswell Islands National Marine Sanctuary, South Central Alaska, USA

Steven Kazlowski / Polar bear (Ursus maritimus) sow and cub sliding on their backs over the pack ice, much like ice skating, 1002 coastal plain of the Arctic National Wildlife Refuge, Alaska, USA

Steven Kazlowski / Moose (Alces alces) bull adult swims across a lake in Denali National Park, Interior of Alaska, summer, USA

Steven Kazlowski / Polar bear (Ursus maritimus) underwater view swimming in a pool, Anchorage Zoo, Alaska, USA. No release available.

Steven Kazlowski / Grizzly bear (Ursus arctos horribilis) young rare blonde (white) bear plays with a young dark coloured bear along the coast of Katmai National Park, Alaskan peninsula, USA

Steven Kazlowski / Lynx (Lynx lynx) adult in the snowy foothills of the Takshanuk mountains, South-East Alaska, USA