A Polar Bear has a 3/4 chance to drop 0-2 Raw Fish and a 1/4 chance to drop 0-2 Raw Salmon. These will always be raw, even if the Polar Bear is on fire when killed.
A Polar Bear cub is always passive. Adult Polar Bears are Neutral unless provoked, in which case they become hostile. They can also become hostile if you get to close to their cubs. If their cubs are attacked, all Polar Bears in a 41x21x41 range will become hostile. If an adult Polar Bear is attacked, all Polar Bears in a 21x21x21 range will become hostile.