Sven Zacek / Sun dog over trees in frosty landscape. Tartumaa, Southern Estonia. December 2015.

Jeff Wilson / Sun Dog, or Parhelion, caused by refraction of the sun's rays, more commonly seen in Antarctica, above glacier, Dry Valleys, Antarctica, December 2009. Taken on location for the BBC series, Frozen Pla...

Bryan and Cherry Alexander / Dog sleds pulled by Huskies (Canis familiaris)crossing sea ice, Northwest Greenland, 1980

Jim Brandenburg / Inuits dog sledding in midnight sun, Ellesmere Island, Nunavut, Canada

Stefan Christmann / Emperor penguins (Aptenodytes forsteri) silhouetted at sunset with a sun dog phenomena, Atka Bay, Queen Maud Land, Antarctica. October.

Ashley Cooper / Sun Island in Almere, which is the Netherlands youngest town, in Flevoland, which was reclaimed from the sea. This planned city is very green, with space heating provided from a nearby combined heat a...

Andrew Walmsley / Batang Toru forests in mist, with sun dog, North Sumatra, Indonesia. This forest is home to a newly identified species of orangutan, the Tapanuli Orangutan (Pongo tapanuliensis) with a population of...

Huw Cordey / African hunting dog (Lycaon pictus) stalking in long grass. Liuwa Plains National Park, Zambia.

LYNN M. STONE / English Setter in grassland with water reflecting sunset, Waterford, Connecticut, USA

Bryan and Cherry Alexander / A sun dog (parhelion / parhelia) in the sky above a truck on a stormy winter's day near Sabetta in the South Tambey Gas Field, Yamal Peninsula, Siberia, Russia. February 2014.

Will Burrard-Lucas / African wild dog (Lycaon pictus) in evening light, South Luangwa National Park, Zambia. June.

Will Burrard-Lucas / African wild dog (Lycaon pictus) in evening light, South Luangwa National Park, Zambia. June.