what about, when the AI are able to attack eachother add cages? so you could somehow catch a bear in a cage (maybe with meat) and when zombies come knocking let the bear maul them? Just a idea

Ala Dwarf fortress doomsday in a box. I like where this idea is going.

But the realy question is why stop at one bear?

pretty much, and i love dwarf fortress, but it sorta feels empty with enemies compared to cataclysm (and i love zombie survival) and yes, why stop at one bear when you can have 10 bears with a mininuke (active) strapped to each one!