Terry Whittaker / Arctic fox (Vulpes lagopus) entering water to swim across river, Hornvik, Hornstrandir Nature reserve, Iceland, July.

Terry Whittaker / Arctic fox (Vulpes lagopus) swimming across river carrying dead guillemot scavenged from the beach before leaving the water and running along beach, Hornvik, Hornstrandir Nature reserve, Iceland, July...

Terry Whittaker / Two Arctic fox (Vulpes lagopus) cubs playing together near den, one cub leaves with the other following close behind, Hornvik, Hornstrandir Nature reserve, Iceland, July.

Terry Whittaker / Three Arctic fox (Vulpes lagopus) cubs following each other out of den, playfighting then walking away, Hornvik, Hornstrandir Nature reserve, Iceland, July.

Terry Whittaker / Three Arctic fox (Vulpes lagopus) cubs playing near den, Hornvik, Hornstrandir Nature reserve, Iceland, July.

Terry Whittaker / Arctic fox (Vulpes lagopus) watching over cubs before walking away, Hornvik, Hornstrandir Nature reserve, Iceland, July.

Terry Whittaker / Four Arctic fox (Vulpes lagopus) cubs playing near den, Hornvik, Hornstrandir Nature reserve, Iceland, July.

Terry Whittaker / Arctic fox (Vulpes lagopus) cub playing with a feather, followed by its sibling taking it before they play together, Hornvik, Hornstrandir Nature reserve, Iceland, July.

Terry Whittaker / Two Arctic fox (Vulpes lagopus) cubs wrestling near den, they are later joined by the other two cubs in the background, Hornvik, Hornstrandir Nature reserve, Iceland, July.

Terry Whittaker / Tracking shot of Arctic fox (Vulpes lagopus) cubs playing near den, Hornvik, Hornstrandir Nature reserve, Iceland, July.