Mark Raycroft / Pronghorn Antelope (Antilocapra americana) running in winter, North America

Mark Raycroft / Pronghorn Antelope (Antilocapra americana) running in winter, North America

Donald M. Jones / Black-capped Chickadee (Poecile atricapillus) in winter, Troy, Montana

Donald M. Jones / Bighorn Sheep (Ovis canadensis) female and male in winter, Jasper National Park, Alberta, Canada

Donald M. Jones / Bighorn Sheep (Ovis canadensis) females in winter, Jasper National Park, Alberta, Canada

Ingo Arndt / Guanaco (Lama guanicoe) herd grazing in winter, Torres del Paine National Park, Patagonia, Chile

Ingo Arndt / Bearded Vulture (Gypaetus barbatus) flying in winter, Valais, Switzerland

Ingo Arndt / Bearded Vulture (Gypaetus barbatus) flying low over snow in winter, Valais, Switzerland

Ingo Arndt / Mountain Lion (Puma concolor) female in snow, Torres del Paine National Park, Patagonia, Chile

Marion Vollborn/ BIA / Whooper Swan (Cygnus cygnus) group taking flight on snow, Hokkaido, Japan

Mark Raycroft / White-tailed Deer (Odocoileus virginianus) buck in snowfall, North America

Alan Murphy/ BIA / Bald Eagle (Haliaeetus leucocephalus) in snowfall, Alaska