Brent Stephenson / A large hole in an iceberg with icicles hanging. Yalour Islands, Antarctic Peninsula, Antarctica, December.

Chadden Hunter / Filming on the Antarctic sea-ice at the edge of a small hole. A cameraman gets a shock when a Killer whale (Orcinus orca) mother and calf explode out of the water in front of his face. Taken on locat...

Eric Baccega / Female Harp seal (Phoca groenlandicus) surfacing at a breathing hole in the sea ice, Magdalen Islands, Gulf of St Lawrence, Quebec, Canada, March 2012

Jeff Wilson / View through the porthole of science teams and Frozen Planet film crew working on the sea ice in the Bering Sea, Alaska, USA, March 2008. The film crew were in search of Spectacled eider ducks, temper...

Bryan and Cherry Alexander / Meltwater pouring off iceberg above hole. Scoresbysund Fiord, East Greenland, September 2005.

Steven Kazlowski / Aerial view of Ringed seals (Phoca hispida) on multi-layer ice (freshwater pans formed over many years where salt is squeezed out of the ice) with exit hole underneath ocean, Chukchi Sea, 20 miles off...

Neil Lucas / Weddell seal (Leptonychotes weddellii) looking up from ice-hole, McMurdo Sound, Ross Sea, Antarctica, November 2008

Neil Lucas / Camerman Doug Allan at frozen water surface of drilled ice hole, BBC film crew, McMurdo Sound, Ross Sea, Antarctica, November 2008

Neil Lucas / Weddell seal (Leptonychotes weddellii) face emerging through sea ice, Ross Sea, Antarctica, November 2008

Neil Lucas / Weddell seal (Leptonychotes weddellii) male surfacing in ice hole, McMurdo Sound, Ross Sea, Antarctica, November 2008

Jerry Monkman / Two young brothers ice fishing on the West River in Brattleboro, Vermont, USA, February 2007. Model released.

Steven Kazlowski / Young Inupiaq woman with Sheefish (Stenodus leucichthys nelma) caught through a hole in pack ice over the Chukchi Sea, for the village elders of Kotzebue, Alaska, March 2008

Doug Allan / Research diver under hole cut in ice. Signy island, Antarctica. Model released.

Mark Brownlow / Rebreather instructor Ian Thomas and cameraman Didier Noirot prepare to dive under the ice, Lake Baikal, world's deepest and oldest (and largest by volume) freshwater lake, Siberia, Russia. BBC Plane...

Doug Allan / Ringed seal at surface hole in ice {Phoca hispida} Lancaster Sound, Canadian Arctic

Michio Hoshino / Harp Seal (Phoca groenlandicus) mother surfacing at ice hole to tend to her newborn pup, Gulf of St Lawrence, Canada

Norbert Wu / Scuba diver exploring ice caves below Weddell Seal (Leptonychotes weddellii) breathing holes, life below feeds on seal feces, Antarctica

Norbert Wu / Weddell Seal (Leptonychotes weddellii) breathing hole is above this ice cave with diver, the cave is filled with Sea Stars (Odontaster validus) that feeds on seal feces, Antarctica

Tui De Roy / Ringed Seal (Phoca hispida) surfacing in brash ice, Svalbard, Norwegian Arctic

Flip Nicklin / Ringed Seal (Phoca hispida) at breathing hole, Arctic

Michio Hoshino / Harp Seal (Phoca groenlandicus) at breathing hole with newborn in background, Gulf of St Lawrence, Canada

Doug Allan / Diver under access hole that has been cut in the sea ice, Antarctica 1987

Doug Allan / Weddell seal with pup surfacing at breathing hole in ice {Leptonychotes weddelli} Antarctica

Sue Flood / Beluga whales caught in ice hole wounded from Polar bear attack. Canadian high arctic. June 1999

Sue Flood / Beluga whales trapped at ice hole {Delphinapterus leucas} too far away to reach open sea, Canadian High Arctic. June 1999

Juergen Freund / Harp seal surfacing at breathing hole searching for pup {Phoca groenlandicus} Magdalen Is, Canada, Atlantic

Sue Flood / Cameraman Doug Allan films Beluga whales surfacing to breathe at ice hole {Delphinapterus leucas} Canadian arctic. On location for Blue Planet, 1999

Steven Kazlowski / Polar bear (Ursus maritimus) female practises breaking a hole in the pack ice, in the 1002 coastal plain of the Arctic National Wildlife Refuge, Alaska, USA

Steven Kazlowski / Polar bear (Ursus maritimus) female practises breaking a hole in the pack ice, in the 1002 coastal plain of the Arctic National Wildlife Refuge, Alaska, USA

Steven Kazlowski / Inupiaq subsistence whalers break open a hole in the pack ice using a harpoon along the edge of an open lead, during spring whaling season, Chukchi Sea, offshore from Barrow, Arctic coast of Alaska

Eric Baccega / Inuit man showing his son the breathing hole of a Bearded seal (Erignathus barbatus) on the ice floe, Ellesmere Island, Nanavut, Canada, June 2012. Model released.

Konrad Wothe / Weddell Seal (Leptonychotes weddellii) in breathing hole, Weddell Sea, Antarctica

Brent Stephenson / A large hole in an iceberg with icicles hanging. Yalour Islands, Antarctic Peninsula, Antarctica, December.

Chadden Hunter / Weddell seal (Leptonychotes weddellii) nostrils visible at icy breathing hole, Antarctica, taken on location for BBC Frozen Planet series, 2009

Eric Baccega / Portrait of a female Harp seal (Phoca groenlandicus) surfacing at breathing hole in the sea ice, Magdalen Islands, Gulf of St Lawrence, Quebec, Canada, March 2012

Eric Baccega / Female Harp seal (Phoca groenlandicus) surfacing at breathing hole looking at her pup, Magdalen Islands, Gulf of St Lawrence, Quebec, Canada, March 2012

Eric Baccega / Two female Harp seals (Phoca groenlandicus) by a breathing hole, one on the sea ice and one surfacing , Magdalen Islands, Gulf of St Lawrence, Quebec, Canada, March 2012

Eric Baccega / Female Harp seal (Phoca groenlandicus) surfacing at breathing hole looks at her pup, Magdalen Islands, Gulf of St Lawrence, Quebec, Canada, March 2012

Eric Baccega / Portrait of a female Harp seal (Phoca groenlandicus) at a breathing hole in the sea ice, Magdalen Islands, Gulf of St Lawrence, Quebec, Canada, March 2012

Eric Baccega / Female Harp seal (Phoca groenlandicus) surfacing at breathing hole and touching noses with her pup, Magdalen Islands, Gulf of St Lawrence, Quebec, Canada, March 2012

Eric Baccega / Female Harp seal (Phoca groenlandicus) with head poking through a breathing hole and pup, Magdalen Islands, Gulf of St Lawrence, Quebec, Canada, March 2012

Eric Baccega / Female Harp seal (Phoca groenlandicus) surfacing at breathing hole touches noses with her pup, Magdalen Islands, Gulf of St Lawrence, Quebec, Canada, March 2012.

Eric Baccega / Profile of a female Harp seal (Phoca groenlandicus) surfacing at breathing hole in the sea ice, Magdalen Islands, Gulf of St Lawrence, Quebec, Canada, March 2012

Doug Allan / Baikal Seal (Pusa sibirica) emerging from hole in the lake ice. Lake Baikal, Siberia, Russia. Freeze frame book plate page page 49.

Doug Allan / Wildlife cameraman Doug Allan prepares for a dive in hole drilled in sea ice. Ross Sea, McMurdo, Antarctica. Freeze frame book plate page 38.

Ernie Janes / Rock with hole in it on West Runton Beach, Norfolk, UK, January

Klaus Echle / Badger (Meles meles) hiding in a drainage tunnel by a snowy stream. Black Forest, Germany, December.

Klaus Echle / Otter (Lutra lutra) surfacing at a hole in ice. Black Forest, Germany, January.

Frederique Olivier / Weddell seal (Leptonychotes weddellii) body print in snow near active tide crack and ice hole, Antarctica, Taken on location for the BBC series, Frozen Planet.

Frederique Olivier / Weddell seals (Leptonychotes weddellii) displaying territorial behaviour at ice hole in tide crack, with Penguin in the background, Antarctica, Taken on location for the BBC series, Frozen Planet.

Bryan and Cherry Alexander / Inuit hunter jigging for cod though a hole in the ice. Igloolik, Nunavut, Canadian Arctic, 1990.

Markus Varesvuo / Water Rail (Rallus aquaticus) foraging at a hole in ice. Finland, January. Magic Moments book plate, page 140.

Markus Varesvuo / Water Rail (Rallus aquaticus) foraging through a hole in ice. Finland, January. Magic Moments book plate, page 141.

Bryan and Cherry Alexander / Edik Seratetto, a young Nenets man, carrying Muksun fish he has caught in a net set under the sea ice and pulled up through an ice hole, Seyakha, Yamal Peninsula, Western Siberia, Russia, March 2011

Bryan and Cherry Alexander / Pyotr and Edik Seratetto, young Nenets men, checking their fishing net set under the sea ice to catch Muksun fish, pulling up fish through the ice hole, Seyakha, Yamal Peninsula, Western Siberia, Russ...

Lassi Rautiainen / Photographer photographing European river otter (Lutra lutra) emerging through hole in ice, industrial site in background, Finland, February 2010

Lassi Rautiainen / European river otter (Lutra lutra) emerging through hole in ice with fish in mouth, Finland, February

Lassi Rautiainen / European river otter (Lutra lutra) portrait at hole in ice, Finland, February

Barrie Britton / Eider (Somateria mollissima) flock roosting in a polynya, an ice hole kept open in the frozen sea by tidal currents. Belcher Islands, Hudson Bay, Canada. Picture taken during filming for the BBC "Pla...

Jenny E. Ross / A female Harp seal (Pagophilus groenlandicus) surfaces at breathing hole, Gulf of St. Lawrence, Nova Scotia, Canada.

Bryan and Cherry Alexander / Ice fishing in hut on Mille Lacs Lake, Minnesota, USA, 1985.

Bryan and Cherry Alexander / Inuit hunter hauling net set under the ice to catch Arctic charr (Salvelinus alpinus). George River, North Quebec, Nunavik, Canada, 1998.

Bryan and Cherry Alexander / Bathers swimming during February in hole in ice covering Lake Semyonovskaya. Murmansk, Northwest Russia, 2005.

Bryan and Cherry Alexander / Inuit hunter hauling dead seal from breathing hole near Cape York, Northwest Greenland.

Bryan and Cherry Alexander / Inuit hunters hauling Bearded seal (Erignathus barbatus) caught at breathing hole. Northwest Greenland, 1980.

Bryan and Cherry Alexander / Inuit hunters butchering Bearded seal (Erignathus barbatus) caught at breathing hole. Northwest Greenland, 1980.

Bryan and Cherry Alexander / Inuit hunters hauling Bearded seal (Erignathus barbatus) caught at breathing hole. Northwest Greenland, 1980.

Bryan and Cherry Alexander / Fur clad Inuk waiting to harpoon seal at breathing hole. Northwest Greenland, 1980.

Bryan and Cherry Alexander / Inuit hunter skinning Ringed seal (Phoca hispida) out on sea ice. Northwest Greenland.

Bryan and Cherry Alexander / Inuit hunter with Ringed seal (Phoca hispida) caught in net under ice. Northwest Greenland.

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 wearing polar bearskin trousers, making hole in sea ice to set net for catching seals. Northwest Greenland, 1996.

Bryan and Cherry Alexander / Breathing hole in sea ice. Arctic seals have a network of these to avoid predators. Northwest Greenland, 1980.

Bryan and Cherry Alexander / Frost smoke rising from open sea at -40C as Inuit hunter waits at seal's breathing hole near floe edge. Thule, Northwest Greenland, 1980.

Bryan and Cherry Alexander / Inuit hunter waiting by seals breathing hole, with harpoon ready. Northwest Greenland, 1980.

Bryan and Cherry Alexander / Inuit hunter dragging seal shot at breathing hole in the sea ice. Scoresbysund, East Greenland, 1974.

Bryan and Cherry Alexander / Inuit hunter using ice chisel to make hole in sea ice for fishing. Igloolik, Nunavut, Canada, 1993.

Bryan and Cherry Alexander / Inuit girl fishing through hole in lake ice. Baffin Island, Nunavut, Canada, 1992.

Bryan and Cherry Alexander / Inuit girl collecting water through hole in lake ice. Baffin Island, Nunavut, Canada, 1992.

Bryan and Cherry Alexander / Inuit hunter jigging for polar cod though a hole in the ice. Igloolik, Nunavut, Canada, 1990.

Neil Lucas / Looking down on Doug Allan climbing out through frozen water from drilled ice-hole in sea ice, underwater filming for BBC Life series, McMurdo Sound, Ross Sea, Antarctica, November 2008

Neil Lucas / Doug Allan, BBC cameraman and another, preparing to enter ice-hole for underwater filming, McMurdo Sound, Ross Sea, Antarctica, November 2008

Neil Lucas / Doug Allan, BBC cameraman and another, entering ice-hole for underwater filming, McMurdo Sound, Ross Sea, Antarctica, November 2008

Neil Lucas / Doug Allan, BBC cameraman, entering ice-hole for underwater filming, McMurdo Sound, Ross Sea, Antarctica, November 2008

Neil Lucas / Doug Allan, BBC cameraman, preparing to enter ice-hole for underwater filming, McMurdo Sound, Ross Sea, Antarctica, November 2008

Neil Lucas / Doug Allan, BBC cameraman and another, preparing to enter ice-hole for underwater filming, McMurdo Sound, Ross Sea, Antarctica, November 2008

Neil Lucas / Doug Allan, BBC cameraman and another, walking across ice to reach ice-hole for underwater filming, McMurdo Sound, Ross Sea, Antarctica, November 2008

Neil Lucas / Ladder leading down into drilled ice-hole for BBC filming, McMurdo Sound, Ross Sea, Antarctica, November 2008

Neil Lucas / Tracked vehicle towing a hut and gas cylinder to ice hole for the BBC film crew, Piston Bully, Ross Sea, McMurdo Sound, Antarctica, November 2008

Neil Lucas / Mummified Weddell seal (Leptonychotes weddellii) trapped in the ice, McMurdo Sound, Ross Sea, Antarctica, November 2008

Neil Lucas / Heavy machinery for drilling through the ice to create an ice-hole for BBC filming crew, McMurdo Sound, Ross Sea, Antarctica, November 2008

Neil Lucas / Heavy machinery for drilling through the ice to create an ice-hole for BBC filming crew, McMurdo Sound, Ross Sea, Antarctica, November 2008

Neil Lucas / Crew watch heavy machinery drilling through the ice to create an ice-hole for BBC filming crew, McMurdo Sound, Ross Sea, Antarctica, November 2008

Neil Lucas / Heavy machinery for drilling through the ice to create an ice-hole for BBC filming crew, McMurdo Sound, Ross Sea, Antarctica, November 2008

Neil Lucas / Cameraman Doug Allan and another from the BBC film crew walking across the ice towards an ice hole, McMurdo Sound, Antarctica, November 2008