Mark Raycroft / Woodland Caribou (Rangifer tarandus caribou) mother nursing calf, Newfoundland, Canada

Loic Poidevin / Reindeer (Rangifer tarandus) calf next to mother's legs, Finland, April.

Richard Kirby / Svalbard reindeer (Rangifer tarandus platyrhynchus) mother and calves, Svalbard, Norway, February.

Bryan and Cherry Alexander / Chukchi girls, with their family's ancestral clan mark painted in reindeer blood on their face, a ritual during the Chukchi 'Festival of the Young Reindeer' during which young reindeer are sacrificed....

Petra Wegner / Mixed Breed puppy, 12 weeks / Pug crossbred, sitting on small sofa with reindeer toy.

Juan Carlos Munoz / Herd of wild Reindeer (Rangifer tarandus) running past young spruce trees in Taiga woodland, Lappland, Finland, March 2007

Bryan and Cherry Alexander / Young Sami girl leading Reindeer (Rangifer tarandus) at start of Spring migration. Kautokeino, Norway, 1972.

Wild Wonders of Europe / de la Lez / Young Svalbard reindeer (Fratercula arctica) lying on ground, Svalbard, Norway, July 2008

Wild Wonders of Europe / de la Lez / Young Svalbard reindeer (Rangifer tarandus platyrhynchus) rubbing its head on adults back, Svalbard, Norway, July 2008

Ingo Arndt / Caribou (Rangifer tarandus) mother and calf crossing a river during summer migration, Arctic National Wildlife Refuge, Alaska

Sergey Gorshkov / Caribou (Rangifer tarandus) mother and calf nuzzling, Kamchatka, Russia

Yva Momatiuk & John Eastcott / Caribou (Rangifer tarandus) young bull in summer tundra, Denali National Park and Preserve, Alaska

Matthias Breiter / Caribou (Rangifer tarandus) calf running on the tundra, Arctic National Wildlife Refuge, Alaska

Asgeir Helgestad / Reindeer bull + calf {Rangifer tarandus} Buskerud, Norefjell, Norway

Asgeir Helgestad / Young Reindeer resting {Rangifer tarandus} Norefjell, Buskerud, Norway

Asgeir Helgestad / Young Reindeer feeding on lichen under snow {Rangifer tarandus} Buskerud, Norway

Jami Tarris / Caribou (Rangifer tarandus) slept on by Tsaatan child, Khovsgol, Mongolia

Espen Bergersen / Young Svalbard reindeer (Rangifer tarandus platyrhynchus) eating. Svalbard, Norway. April.

Roger Powell / Reindeer calf (Rangifer tarandus) feeding on lichen. Sandvik, Porsanger, Finnmark, Norway, May.

Roger Powell / Reindeer (Rangifer tarandus) feeding on lichen, mother with calf suckling. Sandvik, Porsanger, Finnmark, Norway, May.

Roger Powell / Reindeer (Rangifer tarandus) feeding on lichen. Mother and calf Sandvik, Porsanger, Finnmark, Norway, May.

Roger Powell / Reindeer (Rangifer tarandus) mother and calf feeding on lichen, Sandvik, Porsanger, Finnmark, Norway, May.

Erlend Haarberg / Semi-domesticated reindeer (Rangifer tarandus) calf-marking in the Padjelanta National Park, Laponia World Heritage Site, Swedish Lapland, Sweden.

Laurie Campbell / Reindeer (Rangifer tarandus) week old calf sheltering in heather, reintroduced Cairngorm Reindeer herd, Cairngorm National Park, Speyside, Scotland, May.

Laurie Campbell / Reindeer (Rangifer tarandus) week old calf sheltering in heather, reintroduced Cairngorm Reindeer herd, Cairngorm National Park, Speyside, Scotland, May.

Laurie Campbell / Reindeer (Rangifer tarandus) reindeer cow with calf in late spring, reintroduced Cairngorm Reindeer Herd, Cairngorm National Park, Speyside, Scotland May.

Peter Mather / Caribou (Rangifer tarandus) newborn calf nuzzling mother, of the porcupine herd, Arctic National Wildlife Refuge, Alaska

Peter Mather / Caribou (Rangifer tarandus) mother and newborn calf, of the porcupine herd, Arctic National Wildlife Refuge, Alaska

Orsolya Haarberg / Calf marking of domestic Reindeer (Rangifer tarandus) nearby Laddejakka. Every summer the Sami collect all their reindeer, move the herd inside a fenced area, catch the new calves with a snare and mar...

Loic Poidevin / Reindeer (Rangifer tarandus) female and young grazing. Varanger, Norway, May.

Loic Poidevin / Reindeer (Rangifer tarandus) calf suckling. Varanger, Norway, May.

Staffan Widstrand / A reindeer sledding tour experience with sami reindeer herdsmen at the Reindeer Lodge in -25 degrees C, run by Nutti Sami Siida, near the Icehotel, in Jukkasjarvi, Lapland, Laponia, Norrbotten county,...

Erlend Haarberg / Domesticated Reindeer (Rangifer tarandus) calf-marking in the Padjelanta National Park, Laponia World Heritage Site, Swedish Lapland, Sweden July

Erlend Haarberg / Domesticated Reindeer (Rangifer tarandus) calf-marking in the Padjelanta National Park, Laponia World Heritage Site, Swedish Lapland, Sweden July

Erlend Haarberg / Gathering domesticated Reindeer (Rangifer tarandus) with helicopter and motorcycle for calf-marking in the Padjelanta National Park, Laponia World Heritage Site, Swedish Lapland, Sweden July

Erlend Haarberg / Gathering domesticated Reindeer (Rangifer tarandus) with motorcycle for calf-marking in the Padjelanta National Park, Laponia World Heritage Site, Swedish Lapland, Sweden July

Erlend Haarberg / Domesticated reindeer (Rangifer tarandus) calf suckling from female in Padjelanta Nationl Park, Laponia World Heritage Site, Swedish Lapland, Sweden.

Bryan and Cherry Alexander / Nenets woman pushing her baby in a cradle on skiis at the reindeer herders' festival in Nadym. Yamal, Western Siberia, Russia.

Bryan and Cherry Alexander / Young Nenets woman using a mobile phone emerging from reindeer skin tent during the reindeer herders' festival in Nadym. Yamal, Western Siberia, Russia

Bryan and Cherry Alexander / Young Nenets boy sleeping in plastic sled during the Reindeer herders' festival at Nadym. Yamal, Western Siberia, Russia

Bryan and Cherry Alexander / Young Nenets men in traditional clothes at the reindeer herders' festival in Nadym. Yamal, Western Siberia, Russia

Bryan and Cherry Alexander / Young Nenets boy holding balloons at the reindeer herders' festival in Nadym. Yamal, Western Siberia, Russia

Bryan and Cherry Alexander / Two young Nenets men compete in a wrestling competition during the reindeer herders' festival in Nadym. Yamal, Western Siberia, Russia

Bryan and Cherry Alexander / Young Nenets man on a mobile phone wearing traditional reindeer skin clothing during the reindeer herders' festival at Nadym. Yamal, Western Siberia, Russia

Eric Baccega / Nenet woman herding Reindeer (Rangifer tarandus) sleds across tundra with her dog and young child. Yar-Sale district, Yamal, Northwest Siberia, Russia. April 2016.

Eric Baccega / Pet reindeer calf 'akva' (Rangifer tarandus)with Nenet herders preparing for spring migration. Yar-Sale district, Yamal, Northwest Siberia, Russia. April 2016.

Eric Baccega / Nenet woman feeding avka, pet reindeer calf (Rangifer tarandus) in Yar-Sale district, Yamal, Northwest Siberia, Russia. April 2016.

Eric Baccega / Nenet woman feeding pet avka, reindeer calf (Rangifer tarandus). Yar-Sale district, Yamal, Northwest Siberia, Russia. April 2016.

Eric Baccega / Young Nenet boy at camp wearing traditional winter boots made with reindeer skin. Reindeer (Rangifer tarandus) and sled in background. Yar-Sale district. Yamal, Northwest Siberia, Russia. April 2016.

Eric Baccega / Nenet herder on sled with young boy during spring migration wearing traditional coat made with reindeer skin. Yar-Sale district. Yamal, Northwest Siberia, Russia. April 2016.

Benjamin Barthelemy / Juvenile Reindeer (Rangifer tarandus) grazing, with male nearby, Isle of Senja, Troms, Norway, February.

Donald M. Jones / Barren-ground Caribou (Rangifer tarandus groenlandicus) young bull playing in water, central Alaska

Donald M. Jones / Barren-ground Caribou (Rangifer tarandus groenlandicus) young bull playing in water, central Alaska

Donald M. Jones / Barren-ground Caribou (Rangifer tarandus groenlandicus) young bull playing in water, central Alaska

Roland Seitre / Svalbard Reindeer (Rangifer tarandus platyrhynchus) mother and calf running, Spitsbergen, Svalbard, Norway

Loic Poidevin / Young Reindeer (Rangifer tarandus) resting on ground, Finland, June.

Richard Kirby / Svalbard reindeer (Rangifer tarandus platyrhynchus) young, sniffing snow, Svalbard, Norway, February.

Staffan Widstrand / Reindeer (Rangifer tarandus) mother and calf, Laponia World Heritage Area, Lapland, Sweden, July.

Ole Jorgen Liodden / Svalbard reindeer (Rangifer tarandus platyrhynchus) young with antlers in velvet, Spitsbergen, Svalbard

Ole Jorgen Liodden / Svalbard reindeer (Rangifer tarandus platyrhynchus) mother and calf, Spitsbergen, Svalbard, Norway, April.

Erlend Haarberg / Arctic fox (Alopex lagopus) cub chewing on reindeer foot, Dovrefjell-Sunndalsfjella National Park, Norway, July.

Ole Jorgen Liodden / Svalbard reindeer (Rangifer tarandus platyrhynchus) Spitsbergen, Svalbard, Norway, March.

Bryan and Cherry Alexander / The skins and meat from sacrificed young reindeer adorns the inside of a Chukchi Yaranga (tent) during the 'Festival of the Young Reindeer'. Iultinsky District, Chukotka, Siberia, Russia

Bryan and Cherry Alexander / Young girl Nadia Takui eating specially prepared ritual food, including dried reindeer intestine and a sausage made from chopped reindeer meat and fat, during the Chukchi 'Festival of the Young Reind...

Bryan and Cherry Alexander / The men and children of the family place specially prepared food on the ground for the spirits during the Chukchi 'Festival of the Young Reindeer' during which young reindeer are sacrificed. Iultinsk...

Bryan and Cherry Alexander / Reindeer are brought to the camp at first light during the Chukchi 'Festival of the Young Reindeer' begins. Iultinsky District, Chukotka, Siberia, Russia, August 2013.

Bryan and Cherry Alexander / At the end of the Chukchi Festival of Young Reindeer', Rita Votgyrgina, collects small stones to place on burial mound (Melgynvyn) where the powdered bones of sacrificed reindeer are buried, close to...

Bryan and Cherry Alexander / Nadia Takui, a Chukchi girl, dressed in a new Kerker (reindeer skin coverall) stands by a ritual fire at the entrance of a Yaranga (tent) at the start of the Chukchi 'Festival of the Young Reindeer' a...

Bryan and Cherry Alexander / In the evening of the first day of the Chukchi 'Festival of the Young Reindeer', Tamara plays her family's sacred drum in their Yaranga (tent). The Chukchi believe that the sounds of the drum calms th...

Bryan and Cherry Alexander / Yaroslava Votgyrgina, Chukchi girl aged 5 years, watches the proceedings of the Chukchi 'Festival of the Young Reindeer,' at a herders' camp. Iultinsky District, Chukotka, Siberia, Russia, August 2013...

Bryan and Cherry Alexander / Chukchi reindeer herder, Vanya Votgyrgin, walks amongst the reindeer herd with his lasso during the Chukchi 'Festival of the Young Reindeer.' Iultinsky District, Chukotka, Siberia, Russia, August 2013...

Bryan and Cherry Alexander / In the evening of the first day of the Chukchi 'Festival of the Young Reindeer', Tamara plays her family's sacred drum in their Yaranga (tent). The Chukchi believe that the sounds of the drum calms th...

Bryan and Cherry Alexander / Nadia Takui takes Rima Votgyrgina, age 18 months, to watch the reindeer during the Chukchi 'Festival of the Young Reindeer' out on the tundra. Iultinsky District, Chukotka, Siberia, Russia, August 201...

Bryan and Cherry Alexander / Nadia Takui takes Rima Votgyrgina, age 18 months, to watch the reindeer during the Chukchi 'Festival of the Young Reindeer' out on the tundra. Iultinsky District, Chukotka, Siberia, Russia, August 201...

Bryan and Cherry Alexander / Chukchi reindeer herder, Vanya Votgyrgin, walks amongst the reindeer herd with his lasso during the Chukchi 'Festival of the Young Reindeer.' Iultinsky District, Chukotka, Siberia, Russia, August 2013...

Bryan and Cherry Alexander / Yarosalva and Nadia, two Chukchi girls, stand by the entrance of a Yaranga (tent) while Tamara, Nadia's mother, tends a ritual fire at the start of the Chukchi 'Festival of the Young Reindeer' at a he...

Bryan and Cherry Alexander / Volodya Votvyrgyn, a Chukchi reindeer herder, carries a large load of willow branches back to camp. The willow will be used in a religious festival. Iultinsky District, Chukotka, Siberia, Russia, Augu...

Bryan and Cherry Alexander / Yarosalva and Nadia, two Chukchi girls, stand by a ritual fire at the entrance of a Yaranga (tent) and watch the start of the Chukchi 'Festival of the Young Reindeer' at a herders' summer camp. Iultin...

Bryan and Cherry Alexander / The reindeer herd, including a white reindeer, is brought close to the camp for the Chukchi 'Festival of the Young Reindeer.' Iultinsky District, Chukotka, Siberia, Russia, August 2013.

Bryan and Cherry Alexander / Ruslana Votgyrgina, a young Chukchi girl, using a hatchet to chop firewood at a reindeer herders' summer camp. Iultinsky District, Chukotka, Siberia, Russia, August 2013.

Bryan and Cherry Alexander / Rainy afternoon, at the end of the Chukchi 'Festival of the Young Reindeer', the reindeer are taken to their pastures to graze. Iultinsky District, Chukotka, Siberia, Russia, August 2013.

Bryan and Cherry Alexander / Ruslana Votgyrgina, a young Chukchi girl, using a hatchet to chop firewood at a reindeer herders' summer camp. Iultinsky District, Chukotka, Siberia, Russia, August 2013.

Mary McDonald / Reindeer (Rangifer tarandus) young crossing stream, Longyearbyen, Spitsbergen, Svalbard, Norway, Europe

Donald M. Jones / Barren-ground Caribou (Rangifer tarandus groenlandicus) rubbing antlers on sapling to remove velvet, Denali National Park, Alaska

Matthias Breiter / Arctic Fox (Alopex lagopus) pup playing with Caribou (Rangifer tarandus) antler, Churchill, Manitoba, Canada

Sergey Gorshkov / Arctic Fox (Alopex lagopus) pups and mother with Caribou (Rangifer tarandus) antler, Wrangel Island, Russia

Igor Shpilenok / Reindeer (Rangifer tarandus) female with newborn calf by river. Kronotsky Zapovednik Nature Reserve, Kamchatka Peninsula, Russian Far East, October.

Igor Shpilenok / Reindeer (Rangifer tarandus) mother and her baby of a few days. Kronotsky Zapovednik Nature Reserve, Kamchatka Peninsula, Russian Far East, June.

Danny Green / Young reindeer (Rangifer tarandus) in a snowstorm, Norway, March. Bookplate from Danny Green's 'The Long Journey North'

Bryan and Cherry Alexander / Rita Markova, a young Selkup woman, driving a reindeer sled on the frozen Shirta River, Ratta, Krasnoselkup, Yamal, Western Siberia, Russia 2012

Roy Mangersnes / Young male Svalbard reindeer (Rangifer tarandus platyrhynchus) feeding, Spitsbergen, Svalbard, Norway, September

Donald M. Jones / American Badger (Taxidea taxus) mother and kits at den, National Bison Range, Moise, Montana

Michael Quinton / Caribou (Rangifer tarandus) mother and calf, Alaska

Michael Quinton / Caribou (Rangifer tarandus) mother and calf, Alaska

Michael Quinton / Caribou (Rangifer tarandus) females and young, Alaska

Michael Quinton / Caribou (Rangifer tarandus) group jumping fence to cross road, Alaska

Ernie Janes / Bogbean (Menyanthes trifoliata) England, UK, May.

SCOTLAND: The Big Picture / Bogbean (Menyanthes trifoliata) and White waterlily (Nymphaea alba) on lochan with forests and hills beyond. Uath Lochans, Glenfeshie, Cairngorms National Park, Scotland, UK. July.

SCOTLAND: The Big Picture / Bogbean (Menyanthes trifoliata) and White waterlily (Nymphaea alba) on lochan with forests and hills beyond. Uath Lochans, Glenfeshie, Cairngorms National Park, Scotland, UK. July.

Stephen Dalton / Bogbean (Menyanthes trifoliata) in flower. Sussex, England, UK. May.

Willem Kolvoort / Bog-bean (Menyanthes trifoliata) in flower, North Holland. April.

Willem Kolvoort / Bog-bean (Menyanthes trifoliata) in flower, North Holland. April.

Colin Varndell / Bogbean (Menyanthes trifoliata) in flower. Dorset, UK May

Konrad Wothe / Common bogbean (Menyanthes trifoliata) in flower, Bavaria, Germany. June.

Ernie Janes / Bogbean (Menyanthes trifoliata) flowering in garden pond, Norfolk, UK. May.

Ashley Cooper / Bogbean (Menyanthes trifoliata) growing in mountain tarn, Innominate Tarn, Lake District National Park, Cumbria, UK. May.

Nick Upton / Bog bean (Menyanthes trifoliata). Wiltshire, England, UK. May.

Warwick Sloss / Bogbean (Menyanthes trifoliata) flower head in garden pond, Somerset, UK, April.