[@Banana]Ok, SURVEY SAYS 

There is no race of were-bears, however, I will allow one of two things. 
1) You can be a furbolg, which is essentially a Bear Man in the lore. Though, there is no human state. OR 
2) You can be a werewolf that has been cursed by dark sorcery to make you turn into a bear man instead, however you would not know the origins of said curse, because it would be a new, single event thing.