I have spent over 35+ years hiking, backpacking, exploring etc. in what is probably a lot of bear and mountain lion country and other than a few orientation shots by 'babes in the woods' and TWO draw downs on dogs (both called back by the owners) I have never had to use my gun for defense. It bothers me how many reference the need for 'bear and mountain lion' defense when these creatures are more afraid of humans than WE should be of them . If fear of these animals is an issue then maybe it's best those afraid of them stay out of the woods because they are not not the most dangerous things out there.
I've carried a concealed handgun for many years. Never had to use it. Apparently this is proof I don't need one.
I have a fire extinguisher in my truck. Never had to use it. Apparently this is proof I don't need one.
Have homeowners insurance on my house. Never had to use it. Apparently this is proof I don't need it.
Have a first aid kit in my hunting and camping gear. Never had to use it. Apparently this is proof I don't need it.
The reason to chose a gun suitable for the task at hand is not for what HAS happened, but for what MAY happen. Just as it is better to have a gun and not need it as opposed to needing a gun and not having it, it is also better to err on choice of caliber towards more than you need than less than you may need.
If I'm carrying a centerfire rifle in the woods, I generally carry less handgun. If I'm carrying a rimfire in the woods, I generally carry more handgun. I have the luxury of being able to chose from several different handguns. If I had to chose one and only one handgun to do everything, it would probably be at least a .357 Mag since it is the most flexible cartridge for almost all purposes. Size of the frame and barrel length would then become the next choice, dictated by use (concealed carry, target use, plinking, hunting, exposed holster on belt, etc.)
BTW, I have been in very close proximity to bears and coyotes while hunting and hiking. Twice with bears, one time covering one with a handgun at only a few paces. The bear decided to leave. Coyotes several times while hunting them. Turkey hunters here have called in cougars. Hikers were stalked by a cougar on the Ramona Falls trail. A friend calling coyotes used a fawn in distress call and wound up with a very angry cow elk almost in his lap. So while incidents like this may not be common, they certainly are not rare.