Peter Cairns / Polar bear (Ursos maritimus) rolling in the snow on ice floe, Svalbard, Norway, August.

Peter Cairns / Polar bear (Ursos maritimus) on ice floe, Svalbard, Norway, August.

Peter Cairns / Polar bear (Ursus maritimus) on ice floe, Svalbard, Norway, August.

Peter Cairns / Polar bear (Ursus maritimus) on ice floe, Svalbard, Norway, August.

Christophe Courteau / Ice floe and debouching glacier in Borebukta Bay, Spitzbergen, Svalbard, Norway, June, 2012. Composite image.

Christophe Courteau / View from the top of a mast of a sailing boat in pack ice in Woodfjord, Svalbard, Norway, June, 2012.

Christophe Courteau / View from a sailing boat of pack ice in Woodfjord, Svalbard, Norway, June, 2012.

Enrique Lopez-Tapia / Antarctic fur-seal (Artocephalus gazella) on an ice floe. Antarctic Peninsula, Antarctica

Enrique Lopez-Tapia / Antarctic fur-seal (Artocephalus gazella) on an ice floe. Antarctic Peninsula, Antarctica

Enrique Lopez-Tapia / Crabeater seals (Lobodon carcinophaga) on ice floe, Antarctic Peninsula, Antarctica

Enrique Lopez-Tapia / Leopard seal (Hydrurga leptonyx) on an ice floe. Wilhelmina Bay, Gerlache Strait. Antarctic Peninsula, Antarctica

Enrique Lopez-Tapia / Antarctic fur-seal (Artocephalus gazella) on an ice floe. Antarctic Peninsula, Antarctica

Nick Garbutt / Leopard Seal (Hydrurga leptonyx) lying on ice flows, Vernadsky, Antarctic Peninsula, Antarctica.

Tim Laman / Killer whales (Orcinus orca) hunting seals near ice flows. Three killer whales surround a seal (probably a Crabeater seal) Antarctica, February