Heather Angel / Giant panda (Ailuropoda melanoleuca) sliding down slope on back after losing footing. Panda Breeding Centre, Wolong, Sichuan, China. January 1987.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri), four journeying across sea ice to feed young. Atka Bay, Antarctica. August.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) group sliding over ice, returning to form breeding colony. Atka Bay, Antarctica. April.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) group sliding over sea ice, returning to form breeding colony. Iceberg in background. Atka Bay, Antarctica. April 2017.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) group sliding across sea ice to form breeding colony. Atka Bay, Antarctica. April 2017.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) sliding across sea ice in journey to breeding colony. Sastrugi in ice formed by wind erosion. Atka Bay, Antarctica. April.

Frederique Olivier / Emperor penguins (Aptenodytes forsteri) walking in blizzard, Adelie Land, Antarctica, January.

Frederique Olivier / Emperor penguins (Aptenodytes forsteri) walking and tobogganing in blizzard, Adelie Land, Antarctica, January.

Frederique Olivier / Emperor penguin (Aptenodytes forsteri) tobogganing on an iceberg at sunset and diving from the edge, seen from a moving boat, Antarctica.

Ingo Arndt / Emperor penguins (Aptenodytes forsteri) toboganing on ice, Weddell Sea, Antarctica

Tui De Roy / Emperor penguin (Aptenodytes forsteri) tobogganing, Amanda Bay, Prydz Bay, Ingrid Christensen Coast, East Antarctica, November.

Tui De Roy / Emperor penguin (Aptenodytes forsteri) chicks, Amanda Bay, Prydz Bay, Ingrid Christensen Coast, East Antarctica, November.