I carried a Single Six with the .22mag cyl in for protection against cougars(and snakes) for years.
Hung around out in the scrub land, where cougar encounters were fairly normal, with a bunch of ranchers kids. These kids had quite a bit of knowledge about the cats having been around them all of their lives and no one (including me) felt I was undergunned.
This actually would have been an issue because of how frequently we were in the arroyo's where they love to hunt from above and had to protect each others backs. People and livestock were routinely stalked by these cats. You would be walking back to the truck or house and run across the tracks where one was stalking you, hoping one of you ended up alone. It gave you the shivers sometimes when the tracks indicated a big one you knew could take you down.
The officers side arms were more than adequate. The problem was almost certainly that this turned into a persuit type fight.
When we encountered cougars they always seemed to want a clear path to attack you and we saw them at that point. Head shots with a .22mag from that distance while they were still, no problem. Once they realized that we were aware of them they just weren't interested in a fight.
This cat was probably just trying to get away. What a shame they didn't have time to tranquilize it, rehab it, and release it. I don't really like cougars, but its kind of a shame to see one of my old enemies starving then dying scared to death in city. It's a tough old world sometimes
Gaily bedight, A gallant knight In sunshine and in shadow, Had journeyed long, Singing a song, In search of El Dorado