Wildlife documentarian Gordon Buchanan traveled to Svalbard for his new series The Polar Bear Family and Me. He did not know that it is customary there to bring a dish to dinner when visiting the polar bears. The mother expressed their displeasure at this breach of etiquette and tried to break through his protective capsule:
Mr Buchanan, who has filmed the world’s deadliest creatures for 20-years, described the ordeal as his scariest ever experience.
He said: 'A lot of people think that carnivores are intrinsically dangerous but most aren’t - there’s a minimal risk and attacks are the exception.
'But polar bears are different, without a doubt she wanted me for lunch. She was so persistent, looking for a weak spot for almost 45 minutes.
'I was terrified and you could hear my heartbeat on the mic. It really was a sensational moment and a worrying situation.
The quite well-fed looking Polar bear was probably reacting to what, I think was Mr.Buchanan's violation of a custom, a violation of what the bear reckons to be a trade -- humans can enter his or her territory unchallenged in exchange for a small payment, a tidbit (a plate of food to a bear is very small.)
Wolves who live in the wild, feral dogs and other Canidae, like bears have been seen anecdotally, experimentally and otherwise to behave similarly -- just like primates.
Some call this the "Pound of Flesh Principle" that is common to Primates, Canidae and Birds, especially Parrots.
I'm too sleepy to provide references, but here is one, the WikiP executive summary on the Canidae, a group that includes Wolves/Dogs, Bears, Raccoons, Ferrets, Sea-lions, and other doggy-type beings.
http://en.wikipedia.org/wiki/Canidae
(I was trying to be funny here, I think I failed, but I'm not making shit up here...cheers!)