Diane McAllister / Canadian river otter (Lutra canadensis) on a log enjoying its evening meal of a Cutthroat trout, starting at the tail. Trout Lake, Yellowstone National Park, Wyoming, USA, June

Diane McAllister / Canadian river otter (Lutra canadensis) on a log enjoying its evening meal of a Cutthroat trout, starting at the tail. Trout Lake, Yellowstone National Park, Wyoming, USA, June. Winner of the Amateur...

Michael Quinton / Yellowstone Cutthroat Trout (Oncorhynchus clarkii bouvieri) school swimming in stream, Idaho

Michael Quinton / Coyote (Canis latrans) carrying a captured Cutthroat Trout (Oncorhynchus clarki) as a Raven (Corvus corax) looks on, Yellowstone National Park, Wyoming

Michael Quinton / Bald Eagle (Haliaeetus leucocephalus) juvenile with captured Cutthroat Trout (Oncorhynchus clarki), Yellowstone National Park, Wyoming

Michael Quinton / Bald Eagle (Haliaeetus leucocephalus) juvenile with captured Cutthroat Trout (Oncorhynchus clarki), Yellowstone National Park, Wyoming