I had to shoot a mountain lion that was stalking me a couple of decades ago when I was out hiking alone in L.A. I tried several times to scare it away but it kept coming back. Because they are a protected species they have lost all fear of humans. These are ambush predators and it was stalking me from the back and was camouflage and blended well into the environment. It got pretty close and if I didn't know I was being stalked I wouldn't have noticed.
After that unfortunate incident, in addition to my 586 Smith and Wesson .357. I also carried a pellet gun that hopefully would give a decent amount of sting to chase it off. Despite it's appearance and ferocity, mountain lions don't put up the amount of a fight that you think it would and have heard countless stories of how people have fought them off unarmed. If I had know this at the time I would have charged it with a stick (gun still in hand of course) to attempt to scare it off and make it realize that I would not be an easy kill. Of course, I always keep a four inch tanto on me which would help fighting off a cougar if it came to that. I really didn't want to kill it. They are really beautiful and magnificent animals when you see them in the wild. All the big cats are.