As the title says, I'm looking for a lightweight pistol to carry with me when backpacking in areas where animal attacks are at least somewhat of a concern. I'm honestly not a big gun nut, and am just looking for a single pistol to carry as a last-ditch defense against the types of nasties I might run into in, say, national forest land, after I move to Colorado. Frankly, I hope to spend the bulk of my time deep enough in the woods that I'm far more concerned with four-legged predators than the two-legged variety.

My main requirements are:
- Light weight (when I backpack, my base pack weight is 15-20 pounds)
- Ability to stop a mountain lion
- ease of use, including a not-too-ridiculous recoil, so my fiance can fire it
- reasonable cost. Again, I'm no gun nut, so I am not going for super high end fancy stuff here.

Right now, my thinking runs along the lines of compact semiauto .45's. They seem like a decent mix of weight and power for the woods. However, I've never fired one, so that will be a first step to see whether the recoil is something the little lady will be comfortable. I've found several that seem appealing, but am curious if ya'll have any recommendations.

Or, if you think another caliber or style of handgun would be more suited to my needs, I'm all ears - pretty much all of my gun knowledge is what I gleaned from growing up around 30-30's and 30-06's for deer hunting, so I'm pretty much clueless.