Enlarge / Polar bear fur insulates even when wet. (credit: Mario Hoppmann)

Personal heating products have always scared me. The idea of getting into a bed with an electric blanket appeals about as much as a romantic bath with my toaster. So when researchers propose a shirt that you plug into the mains, my response is: yeah, nah.

But the research is quite interesting, made even better by the inclusion of a gratuitous polar bear picture. Polar bears, according to Chris’s compendium of tru facs (patent pending), are most famous for being the animal least-likely to express regret after accidentally chewing off your left foot. Equally famously, polar bears seem to be able to cope with some rather cold weather. It is this latter fact that has caught the attention of researchers who have replicated the insulating properties of polar bear fur in a weavable thread.

Polar bear fur faces some tough challenges. Being insulating is not enough: it also needs to maintain that insulation when the bear’s coat is soaked through after swimming from one ice floe to another. For fair-weather animals, this would be deadly, because their insulation mostly relies on the air trapped between hairs. Since air is a poor heat conductor, trapped air provides remarkably good insulation. Unfortunately, a prolonged swim will remove all the air, replacing it with water. Water is a much better heat conductor, so body heat is sucked away from a sodden animal at a deadly rate in cold conditions.