Polar bear (Ursus maritimus) standing on coastal rocks wearing a satellite tracking collar around its neck. This bear, the world's largest land predator, is found throughout the Arctic circumpolar regions, although its range is limited by the extent of the pack ice. A male polar bear can weigh up to 600 kilograms and measure 2.6 metres in length. It hunts prey both on land and in the water. Satellite tracking devices are used to monitor the movements of polar bears to aid research into how they are being endangered by the effects of global warming. Photographed in July 2015, in Norway's Svalbard archipelago in the Arctic.