Sure, you know that polar bears are threatened, but how far does your knowledge extend beyond that? The Sierra Club wants to put you to the test. Do you know how many cubs can a polar bear give birth to at a time, for example, or whether all polar bears are left-handed. What color are they underneath all that brilliantly white fur? The answers may surprise you. ::Sierra Club

See also: ::Track Polar Bears along Hudson Bay

Difficulty level: Easy