Senior author Bodil Holst, a physicist at the University of Bergen in Norway, was inspired to investigate polar bear fur after watching a TV quiz program, she tells Michael Le Page at New Scientist.

That's because polar bear fur is transparent and hollow.When light strikes the outer fur some of it is absorbed while the rest is scattered away. The result? The fur can appear as different colors ...

“It’s something that I had never really thought deeply about: is there something unique about their fur?” Applying each group’s research strengths, the team demonstrated that the oils in polar bear ...