Espen Bergersen / Two Svalbard reindeer (Rangifer tarandus platyrhychus) Svalbard, Norway, April.

Espen Bergersen / Svalbard reindeer (Rangifer tarandus platyrhynchus) in distance at sunset, Svalbard, Norway. April.

George Sanker / White-tailed deer (Odocoileus virginianus) female grazing in snow, Acadia National Park, Maine, USA. February.

George Sanker / White-tailed deer (Odocoileus virginianus) females grazing in snow, Acadia National Park, Maine, USA. February.

George Sanker / American buffalo (Bison bison) with group of calves, Yellowstone National Park, Wyoming, USA. May.

Sean Crane / African Elephant (Loxodonta africana) mother and calf grazing, Lewa Wildlife Conservancy, Kenya

Sean Crane / African Elephant (Loxodonta africana) mother and calf grazing, Lewa Wildlife Conservancy, Kenya

Denis-Huot / African elephant (Loxodonta africana) herd eating, Masai-Mara Game Reserve, Kenya

Roland Seitre / Przewalski's horse (Equus ferus przewalskii) grazing in buttercups, Parc de la Haute Touche, Obterre, France. May. Captive, occurs in Central Asia.

Pete Oxford / Marine Iguana (Amblyrhynchus cristatus) feeding on algae in water, Fernandina Island, Galapagos Islands, Ecuador

Pete Oxford / Galapagos Giant Tortoise (Chelonoidis nigra) grazing, Santa Cruz Island, Galapagos Islands, Ecuador

Tui De Roy / Marine Iguana (Amblyrhynchus cristatus) feeding on algae, Punta Espinosa, Fernandina Island, Galapagos Islands, Ecuador