Yes
Yes. Although it is extremely rare, polar bears may kill or eat smaller bears, or kill cubs from another bear.
PolAt bear have a diet on seals artic foxes fish etc there not many animals that feed on the bear itself none I don't think part from humans :)
Polar Bears are alot like humans: Eat other animals, starts a baby then grows into an adult, and mammals. They also are like us because if it is a cannibal Polar Bear then yes it would, but that...
Male polar bears sometimes do this to cubs of other males so that the female will be ready to breed again with them.