There are no grizzlies where I live, and the black bears I have encountered usually head the other way. My cousins adult daughter was attacked last fall while she was sitting in her treestand bow hunting for deer. She had to get 65 stitches in her leg.

Here is a link to some videos and testimonials from people who were attacked by bears and other animals and used pepper spray.

I carry a 4oz can of pepper spray when I'm in the wilderness and not hunting. In my opinion, that will be sufficient protection for the most likely scenarios, including two legged predators.

http://www.udap.com/testify.htm