Donald M. Jones / Elk (Cervus elaphus) bull browsing in winter, Montana

Donald M. Jones / Elk (Cervus elaphus) female grazing on dry grass in winter, Alberta, Canada

Donald M. Jones / Common Redpoll (Carduelis flammea) in winter, Montana

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

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

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

Donald M. Jones / American Bison (Bison bison) in winter, National Bison Range, Montana

Chase Dekker / Blue Jay (Cyanocitta cristata) in snowfall, Algonquin Provincial Park, Ontario, Canada

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

Ingo Arndt / Mountain Lion (Puma concolor) stepping into Guanaco (Lama guanicoe) tracks in snow during stalk, Torres del Paine National Park, Patagonia, Chile

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

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