Polar Bears have very thick fur. Their fur is like little straws. They trap air inside to keep them warm.
They have two layers of fur the outside fur keeps them dry.
It may look like a toilet roll, but these tubes are polar bear 'guard' hairs - the coarse outer layer that protects the finer under-fur from the elements. Although they look white, they are translucent and each air-filled hollow heat-proofs the bear
Their fur is white so they can hide against the snow and sneak up on a seal.