Stefan Christmann / Emperor penguin (Aptenodytes forsteri) breeding colony, adults brooding chicks. Atka Bay, Antarctica. September 2017.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri), two chicks aged six to eight weeks huddling together. Atka Bay, Antarctica. September.

Jussi Murtosaari / Blackcap (Sylvia atricapilla) female and two males huddling together for warmth while sleeping, Finland, May.

Frederique Olivier / Close-up of a group of Emperor penguin (Aptenodytes forsteri) chicks huddled together in a blizzard, covered in snow, Adelie Land, Antarctica, January.

Frederique Olivier / Emperor penguin (Aptenodytes forsteri) chicks huddled together during a blizzard, Adelie Land, Antarctica, January.

Konrad Wothe / Chimpanzee (Pan troglodytes) sitting in the rain, Mahale Mountains National Park, Tanzania.

Cyril Ruoso / Golden monkey (Rhinopithecus roxellana) females sitting close together with baby inbetween, Qinling Mountains, China.

Tui De Roy / Little blue / fairy penguin (Eudyptula minor) walking on pathway to nesting burrows, Neck Game Reserve, Bruny Island, Tasmania, Australia, December.

Sergey Gorshkov / Musk ox (Ovibos moschatus) herd, Wrangel Island, Far Eastern Russia, March.

Sergey Gorshkov / Musk ox (Ovibos moschatus) portrait, Wrangel Island, Far Eastern Russia, March.

Cyril Ruoso / Ring-tailed Lemur (Lemur catta) group huddles for warmth as they sleep, vulnerable, Berenty Private Reserve, Madagascar

Andrew Parkinson / Mountain hare in winter coat rests in snow drift {Lepus timidus} Scotland, UK