The Inside Nature's Giants experts join the expedition to carry out an anatomical dissection to explore some of the mysteries of the polar bear. Veterinary scientist Mark Evans is upset by his first encounter with a freshly-hunted polar bear. Comparative anatomist Professor Joy Reidenberg is astonished by the thickness of the polar bear's fur and even more surprised to discover that while its skin is black and its fur translucent, the polar bear still appears white. The programme asks how they cope with such a high fat diet of seal blubber without risking heart failure. And, out on the ice, Simon Watt crawls inside a recently evacuated polar bear den and traces their remarkable evolutionary story. As their habitat melts and their food becomes increasingly contaminated, the polar bears' future looks precarious. Can they adapt fast enough to survive this rapidly changing world?