Southern elephant seal (Mirounga leonina) challenger bull head detail at Gold Harbour on South Georgia Island, Polar Regions

Bull southern elephant seal (Mirounga leonina) on South Georgia Island, Southern Ocean

Southern elephant seal (Mirounga leonina) pup, called weaners once their mothers stop nursing, South Georgia Island, Southern Ocean

Southern right whale (Eubalaena australis) calf surfacing near Puerto Pyramides, Golfo Nuevo, Peninsula Valdez, Argentina

Bull southern elephant seal (Mirounga leonina) on South Georgia Island, Southern Ocean

Adult Dall sheep (Ovis dalli) in Denali National Park, Alaska, United States of America

The white flipper band of a Minke whale (Balaenoptera acutorostrata) is visible through the greenish water. This distinctive feature is characteristic of Minke whales of the northern hemisphere and the most obvious difference to their relatives in the Antarctic. St. Lawrence estuary, Canada

Tall dorsal fin of a Finback whale (Balaenoptera physalus) which is located far back along the dorsal ridge. This prominent feature is often used for identification. St. Lawrence estuary, Canada

Minke whale (Balaenoptera acutorostrata) surfacing in the green coloured water. Although exposed, she still has both blowholes tightly closed. Note the pronounced ridge on the rostrum, a main feature of rorqual whales. St. Lawrence estuary, Canada Sequence 1/2.

Two horses in front of barn, USA, Colorado

Atlantic walrus (Odobenus rosmarus) with its most prominent feature the long tusks, coming close to check the photographer, Spitsbergen, Svalbard, Norwegian archipelago, Norway, Arctic Ocean