Why are bears in yaoi animes? In Yaoi I have fairly noticed a highly recurring thing which is Bears. In particular I am aiming this at Yaoi's such as Sekai Ichi Hatsukoi and Junjou Romantica.

Examples:


 

So my question is what is the relationship between the re-occurring bears seen in Yaoi's such as Sekai Ichi Hatsukoi and Junjou Romantica and are bears related to homosexuals in yaoi? and where did the idea of bears come from? Why bears?
I'm no expert, but sometimes a member of a gay couple can be called a Bear. This man is usually rugged and macho, and usually hairy. 

Wikipedia describes a Teddy Bear as:


  A fully hairy Bear. Chest, back, beard, everything is hairy


So perhaps this is a reference to that, seeing as you mention it occurs significantly often in yaoi?