10 year-old Border Terrier dog, Jess, sitting in the sunshine in a country garden, England

Mother elephant and calf in woodland in Moremi National Park, Botswana

Male Impala with curved horns chasing and scenting a female, Grumeti, Tanzania

Portrait of a Bengal tiger (Panthera tigris tigris) walking through grass in forest towards camera, Madhya Pradesh, India

Portrait of Bengal tiger (Panthera tigris tigris) lying beside waterhole, watching camera, Madhya Pradesh, India

Grizzly bear (Ursus arctos horribilis) surrounded by fall foliage in Denali National Park, Denali National Park & Preserve, Interior Alaska, Alaska, United States of America

Portrait of a bull moose (Alces alces) walking through an alpine meadow late in the rut in Southcentral Alaska's Chugach State Park, Alaska, United States of America

Close-up portrait of a collared pika (Ochotona collaris) pausing on a boulder in mid-August with a hank of wild grass in its mouth in Southcentral Alaska's Hatcher Pass in the Talkeetna Mountains north of Palmer, Alaska, United States of America

View taken from behind of silhouettes of two blue wildebeest (Connochaetes taurinus) standing on the savanna watching a cheetah (Acinonyx jubatus) pass by, Serengeti National Park, Tanzania, Africa

Close-up portrait of a Bengal tiger (Panthera tigris tigris) standing in the forest looking up, Madhya Pradesh, India

Close-up portrait of Bengal tiger (Panthera tigris tigris) lying down in the grass, watching the camera, Madhya Pradesh, India

Close-up of the clasped hands of a mixed race couple, holding hands and spending quality time together during a fall family outing in a city park, Edmonton, Alberta, Canada

Close-up of a young lion (Panthera leo) sitting in the grass, turning head, Laikipia, Kenya

Portrait of Bengal tiger (Panthera tigris tigris) lying beside waterhole, watching camera, Madhya Pradesh, India

Portrait of a sunlit, wolf (Canis lupus) standing in the brush in the snow, Churchill, Manitoba, Canada

Portrait of a Polar bear (Ursus maritimus) lying in the snow looking out from behind a snowbank, Churchill, Manitoba, Canada

Portrait of a red fox (Vulpes vulpes) standing in the grass watching intently while hunting on a frosty October morning in Southcentral Alaska, Anchorage, Alaska, United States of America

Close-up portrait of a Canada Lynx (Lynx canadensis) resting in the shadows of a Southcentral Alaska alder thicket. Lynx populations are closely linked to booms and busts in the numbers of their main prey the snowshoe hare, Alaska, United States of America

Close-up portrait of a young male lion (Panthera leo leo) lowering head, Serengeti National Park, Tanzania, Africa

Portrait of a polar bear (Ursus maritimes) standing in the snow looking at the camera, Churchill, Manitoba, Canada

A collared pika (Ochotona collaris) pausing on the alpine tundra at Southcentral Alaska's Hatcher Pass, high in the Talkeetna Mountains north of Palmer in late August, Alaska, United States of America

Portrait of a black bear (Ursus americanus) pausing on a mountainside from feeding on lowbush cranberries and looking at the camera on a mid-October afternoon in Southcentral Alaska's Chugach Mountains, Alaska, United States of America

Close-up portrait of a Canada Lynx (Lynx canadensis) looking at the camera through the branches of a Southcentral Alaska alder thicket. Lynx populations are closely linked to booms and busts in the numbers of their main prey the snowshoe hare, Alaska, United States of America

Close-up of the clasped hands of a mixed race couple, holding hands and spending quality time together during a fall family outing in a city park, Edmonton, Alberta, Canada

Close-up portrait of the profile of a red fox (Vulpes vulpes) looking up and testing the wind while hunting on a frosty, October morning in South Central Alaska, Anchorage, Alaska, United States of America

Close-up portrait of the profile of a red fox (Vulpes vulpes) pausing while hunting on a frosty October morning in South Central Alaska, Anchorage, Alaska, United States of America

Mono, close-up portrait of a Cape Buffalo (Syncerus caffer) standing, eyeing camera in Segera, Segera, Laikipia, Kenya