Слишком упрощённо, как вообще многое у малоизученных зверей.
http://forests.org/articles/reader.asp?linkid=28776

"Yet young bears are not pussycats. "I have seen a number of times when two little bears, on being approached by a much bigger bear, will stand shoulder-to-shoulder and make the big bear back off," said Dr. Jane Waterman of the University of Central Florida.Dr. Waterman and her husband, Dr. Roth, together study play behavior among male polar bears. They have observed bears congregating in Churchill in the fall, waiting for the sea ice to form, allowing them to get back to the main glacial plain and begin hunting for seals and, later in the season, mating. The females tend to keep quiet and off by themselves, but not the males. Instead, the males play, in pairs. They rear up on their hind legs and wrestle with each other. They lock mouths. They embrace. They seem to dance. They flop down next to each other for breaks, get up and start horsing around again. All the play is frisky, but gentle, amicable, and in stark contrast to the violent clashes among males during mating season, six months later.

"The big question is, Why are they doing it?" said Dr. Roth. "It takes a lot of energy for large animals to play, and they've just been fasting for months."

The researchers are now testing several hypotheses: that the males are establishing a dominance hierarchy; that they are measuring their personal prowess to see how well they will be able to defend their hard-caught seals against thieves; that they are practicing for the mating season; that they are getting in shape after months of indolence; or that they are building alliances, and making friends. Hard times lie ahead. Why not grin and bear it together?"