Mark Raycroft / Siberian Husky (Canis familiaris) in snow

Mark Raycroft / Siberian Husky (Canis familiaris)

Mark Raycroft / Siberian Husky (Canis familiaris) in snow

Mark Raycroft / Siberian Husky (Canis familiaris) sled dog

Mark Raycroft / Siberian Husky (Canis familiaris) group tied to sled

Mark Raycroft / Siberian Husky (Canis familiaris)

Mark Raycroft / Siberian Husky (Canis familiaris) in snow

Mark Raycroft / Siberian Husky (Canis familiaris)

Bryan and Cherry Alexander / Forest Nenet women travelling by Reindeer / Caribou (Rangifer tarandus) sled near Numto. Khanty Mansiysk, Western Siberia, Russia, 2000.

Bryan and Cherry Alexander / Nenets herder leading his Reindeer / Caribou (Rangifer tarandus) sled along the main street in the village of Yar-Sale, Yamal, Siberia, Russia, 1993.

Bryan and Cherry Alexander / Komy woman returning to herders' camp with Reindeer / Caribou (Rangifer tarandus) sled. Yamal, Western Siberia, Russia, 2003.

Bryan and Cherry Alexander / Komy herders with Reindeer / Caribou (Rangifer tarandus) travelling across the Nadym tundra in Spring. Yamal, Western Siberia, Russia, 2003.

Bryan and Cherry Alexander / Forest Nenets girl travelling on sled pulled by Reindeer / Caribou (Rangifer tarandus) in Khanty Mansiysk, Russia, 2000.

Bryan and Cherry Alexander / Nenets man driving Reindeer / Caribou (Rangifer tarandus) sled during Spring migration. Yamal, Western Siberia, Russia, 1993.

Angelo Gandolfi / Horse-drawn sledge, with two men on board, Crna Vlast village, Plitvice Lakes National Park, Croatia.

Bryan and Cherry Alexander / Reindeer / Caribou (Rangifer tarandus) herd travelling on frozen Layvaya Hetta River in Khanty Mansiysk, Western Siberia, Russia, 2000

Bryan and Cherry Alexander / Competitors on the final straight of a Reindeer / Caribou (Rangifer tarandus) race at Jokkmokk winter market, Sweden.

Bryan and Cherry Alexander / Khanty woman travelling on sled pulled by Reindeer / Caribou (Rangifer tarandus) at sunset near Numto. Khanty Mansisyk, Siberia, Russia, 2000.

Bryan and Cherry Alexander / Nganasan elder driving sled pulled by Huskies (Canis familiaris) on the frozen Kheta River. Taymyr, Northern Siberia, Russia, 2004.

Bryan and Cherry Alexander / Nganasan girl standing on sled with Huskies (Canis familiaris) near the Kheta River. Taymyr, Northern Siberia, Russia, 2004.

Bryan and Cherry Alexander / Nenets woman leading Reindeer / Caribou (Rangifer tarandus) sled loaded with firewood. Yamal, Western Siberia, Russia, 2001.

Bryan and Cherry Alexander / Nenets girl feeding bread to Reindeer / Caribou (Rangifer tarandus) during migration. Yamal, Siberia, Russia, 1993.

Bryan and Cherry Alexander / Khanty and Nenets herders travelling by sled pulled by Reindeer / Caribou (Rangifer tarandus). Khanty Mansisyk, Siberia, Russia, 2000.

Bryan and Cherry Alexander / Nenets girl driving Reindeer / Caribou (Rangifer tarandus) sled past drilling rig in Gazprom's Bovanenkovo field. Yamal, Western Siberia, Russia, 1993.

Bryan and Cherry Alexander / Nenets girl driving Reindeer / Caribou (Rangifer tarandus) sled past debris in Gazprom's Bovanenkovo gas field. Yamal, Siberia, Russia, 1993.

Bryan and Cherry Alexander / Nenets baby in a cradle on wooden sled at Reindeer / Caribou herders' winter camp. Yamal, Western Siberia, Russia, 1996.

Bryan and Cherry Alexander / Nenets Reindeer / Caribou herder bending larch planks into sled runners over fire. Yamal, Siberia, Russia, 1996.

Bryan and Cherry Alexander / Nenets sled Reindeer / Caribou (Rangifer tarandus) grazing on Sedges (Carex sp). Yamal Peninsula, Siberia, Russia, 1993.

Bryan and Cherry Alexander / Nenets girl driving Reindeer / Caribou (Rangifer tarandus) sled across summer tundra. Yamal, Siberia, Russia, 1993.

Petra Wegner / Sacred Cat of Burma / Birman / Birman, portrait of blue-tabby-point, sitting on toboggan in snow, with picket fence behind

Petra Wegner / Sacred Cat of Burma / Birman / Birman, portrait of kitten, aged 8 weeks, standing on toboggan in snow, with picket fence behind

Petra Wegner / Sacred Cat of Burma / Birman / Birman, portrait of blue-tabby-point, sitting on toboggan in snow, with picket fence behind

Petra Wegner / Sacred Cat of Burma / Birman / Birman, portrait of kitten, aged 8 weeks, lying on toboggan in snow, with picket fence behind

Petra Wegner / Two Sacred Cats of Burma / Birman, portrait of kittens, aged 8 weeks, on toboggan in snow, with picket fence behind

Petra Wegner / Sacred Cat of Burma / Birman / Birman, portrait of blue-tabby-point, sitting on toboggan in snow, with picket fence behind

Petra Wegner / Sacred Cat of Burma / Birman / Birman, portrait of kitten, aged 8 weeks, sitting on toboggan in snow, with picket fence behind

Petra Wegner / Sacred Cat of Burma / Birman / Birman, portrait of blue-tabby-point, sitting on toboggan in snow, with picket fence behind

Petra Wegner / Sacred Cat of Burma / Birman / Birman, portrait of blue-tabby-point, sitting on toboggan in snow, with picket fence behind

Petra Wegner / Sacred Cat of Burma / Birman / Birman, portrait of chocolate tabby-point tomcat, sitting on toboggan in snow, with picket fence behind

Petra Wegner / Papillon / Continental Toy Spaniel / Butterfly Dog, portrait lying on rug covered toboggan in snow, with picket fence behind

Bryan and Cherry Alexander / Dolgan Reindeer / Caribou (Rangifer tarandus) herders moving their camp of baloks (huts on sled runners) during winter. Taymyr, Northern Siberia, Russia, 2004.

Bryan and Cherry Alexander / Dolgan Reindeer / Caribou (Rangifer tarandus) herders moving their camp of baloks (huts on sled runners) during winter. Taymyr, Northern Siberia, Russia, 2004.

Bryan and Cherry Alexander / Dolgan Reindeer / Caribou (Rangifer tarandus) herders moving their camp of baloks (huts on sled runners) during winter. Taymyr, Northern Siberia, Russia, 2004.

Bryan and Cherry Alexander / Snow covered sled dog (Canis familiaris) during storm at Dezhnovka. Uelen, Chukotka, Siberia, Russia.

Bryan and Cherry Alexander / Sled dogs (Canis familiaris) covered in snow during autumn storm at Dezhnovka. Uelen, Chukotka, Siberia, Russia.

Bryan and Cherry Alexander / Dolgan Reindeer / Caribou (Rangifer tarandus) herders moving their camp of baloks (huts on sled runners) during winter. Taymyr, Northern Siberia, Russia, 2004

Bryan and Cherry Alexander / Inuit hunter walking beside dog sled across thin sea-ice. Savissivik, Northwest Greenland, 1991.

Bryan and Cherry Alexander / Inuit hunter running to jump onto moving sled pulled by Huskies (Canis familiaris). Savissivik, Northwest Greenland, 1998.

Bryan and Cherry Alexander / Inuit hunter resting on sled while hunting in Melville Bay, Northwest Greenland, 1998.

Bryan and Cherry Alexander / Inuit hunters butchering Bearded seal (Erignathus barbatus) and loading meat onto sled. Northwest Greenland, 1980.

Bryan and Cherry Alexander / Inuit hunter loading Polar bear (Ursus maritimus) meat onto sled. Northwest Greenland, 1980.

Bryan and Cherry Alexander / Polar bear (Ursus maritimus) skin hanging from dog sled. Northwest Greenland, 1980.

Bryan and Cherry Alexander / Inuk on sled pulled by Huskies (Canis familiaris) celebrating successful hunt. Northwest Greenland, 1980.

Bryan and Cherry Alexander / Inuit hunter standing on sled pulled by Huskies (Canis familiaris) for better view across sea ice. Northwest Greenland, 1980.

Bryan and Cherry Alexander / Inuit hunter resting on sled while his Huskies (Canis familiaris) wait. Northwest Greenland, 1980.

Bryan and Cherry Alexander / Sea ice with ice flowers, Inuk and dog sled beyond. Melville Bay, Northwest Greenland, 1980.

Bryan and Cherry Alexander / Inuit hunters travelling by dog sled pulled by Husky dogs (Canis familiaris) on seal hunt in spring. Northwest Greenland, 1977.

Bryan and Cherry Alexander / Inuit using boat to transport sled. Qeqertat, Northwest Greenland, 1977.

Bryan and Cherry Alexander / Inuit hunters travelling to floe edge in boat on sled pulled by Huskies (Canis familiaris). Siorapaluk, Northwest Greenland, 1977.

Bryan and Cherry Alexander / Inuit hunter driving his dog sled on snow free ground in Robertson Fjord during Summer. Northwest Greenland, 1989.

Bryan and Cherry Alexander / Inuit hunter travelling by dog sled pulled by Huskies (Canis familiaris) over rough pressure ice. Northwest Greenland.

Bryan and Cherry Alexander / Inuit hunters travelling by dog sled pulled by Huskies (Canis familiaris) on sea ice near Cape Atholl, Northwest Greenland.

Bryan and Cherry Alexander / Inuk hunter shaping upstander for traditional sled. Thule, Northwest Greenland, 1985.

Bryan and Cherry Alexander / Inuit hunter with dog sled viewed through hole in iceberg near Savissivik. Northwest Greenland, 1996.

Bryan and Cherry Alexander / Inuit hunter with dog sled viewed through hole in iceberg near Savissivik. Northwest Greenland, 1996.

Bryan and Cherry Alexander / Inuit hunter loading dead seal onto sled near Savissivik. Northwest Greenland, 1996.

Bryan and Cherry Alexander / Dog sled crossing sea ice across Meteorite Bay. Savissivik, Northwest Greenland, 1996.

Bryan and Cherry Alexander / Inuit man tying boots onto sled dog (Canis familiaris) to protect feet from sharp ice crystals of early summer. Northwest Greenland, 1980.

Bryan and Cherry Alexander / Inuit man tying boots onto sled dog (Canis familiaris) to protect feet from sharp ice crystals of early summer. Northwest Greenland, 1980.

Bryan and Cherry Alexander / Inuit hunter relaxing on sled during Spring journey by dog sled. Thule, Northwest Greenland, 1980.

Bryan and Cherry Alexander / Reindeer (Rangifer tarandus) on sled alongside lorry for bulk transportation. Karasjok, Norway, 2000.

Bryan and Cherry Alexander / Exhausted Reindeer (Rangifer tarandus) calves riding on sled behind snowmobile, North Norway, 1985.

Bryan and Cherry Alexander / Huskies (Canis familiaris) pulling sled carrying tourists on trip near Jukkasjarvi, Sweden, 2003.

Bryan and Cherry Alexander / Lake Sami man travelling by 'Pulka,' traditional sled pulled by Reindeer (Rangifer tarandus). Inari, North Finland, 1996.

Bryan and Cherry Alexander / Elderly Cree man in snowshoes hauling birchwood sled. Quebec, Canada, 1988.

Bryan and Cherry Alexander / Inuk driving his snow scooter with a family box on the sled, Pond Inlet, Nunavut, Canada, 1999.

Bryan and Cherry Alexander / Inuk pushing sled over ice ridge, helped by Huskies (Canis familiaris). Igloolik, Nunavut, Canada, 1993.

Bryan and Cherry Alexander / Huskies (Canis familiaris) pulling sled across sea ice in wind near Igloolik, Nunavut, Canada, 1993.

Bryan and Cherry Alexander / Inuit hunter travelling by dog sled under midnight sun. Igloolik, Nunavut, Canada, June 1992.

Bryan and Cherry Alexander / Inuit boy playing with a sled on the sea ice. Arctic Bay, Baffin Island, Nunavut, Canada, 2005.

Eric Baccega / Dog pulling sled on Giant kangia fjord, Disko Bay, Greenland, July 2002

Jerry Monkman / Young boys sledding at Wagon Hill Farm in Durham, New Hampshire, USA, January 2009. Model released.

Jerry Monkman / Young girls sledding at Wagon Hill Farm in Durham, New Hampshire, USA, January 2009.

Wild Wonders of Europe / Liodden / Sled dog (Canis familiaris) sleeping in snow, Spitsbergen, Svalbard, March 2009

Roy Mangersnes / Sled dog resting, covered in snow, minus 20 degrees centigrade, West coast of Spitsbergen, Svalbard, Norway, March

Staffan Widstrand / Rear view of Reindeer (Rangifer tarandus) pulling sled on sledding safari tour, Övre Soppero, Lapland, Norrbotten, Sweden, April 2007

Staffan Widstrand / Reindeer (Rangifer tarandus) pulling sled on sledding safari tour, Övre Soppero, Lapland, Norrbotten, Sweden, April 2007

Staffan Widstrand / Reindeer (Rangifer tarandus) pulling sled on sledding safari tour, Övre Soppero, Lapland, Norrbotten, Sweden, April 2007

Juan Carlos Munoz / Team of dogs pulling sledge over snow, Dovrefjell National Park, Norway, April 2009

Juan Carlos Munoz / Team of dogs pulling sledge over snow, Dovrefjell National Park, Norway, April 2009

Juan Carlos Munoz / Team of dogs pulling sledge over snow, Dovrefjell National Park, Norway, April 2009

Jasper Doest / Dog (Canis familiaris) team pulling sled, Abisko, Sweden

Jasper Doest / Dog (Canis familiaris) team pulling sled, Abisko, Sweden

Jerry Monkman / A sled dog team starting their run in the Sandwich Notch 50 sled dog race, Sandwich, New Hampshire, USA.

Roy Mangersnes / Man on skis pulling a pulk sled across snow covered mountain with shadow and blue sky backdrop. Norway, March

Colin Monteath / Person skiing across snow from Ny Alesund to Longyearbyen, Spitsbergen, Svalbard, Norway