If you choose to trail run in mountain lion country, a bell may scare off bears, but may have the opposite effect for mountain lions. Stay aware, don't wear headphones or zone out on the trail.
I have seen three separate stalk and harvest events, the cow elk was my first and closest. My second was a wild burro colt. The the third was an old javelina (collared peccary). The second was by far the scariest, as the puma actually bit over the mouth and nose of the colt and suffocated it.
Fear is the correct emotion with regards to these wild animals. If you want to see one, the Arizona Sonora Desert Museum (really a zoo, in spite of the name) is the best and safest way I know about. I would never willingly try to find one in the wild unless i had a hunting permit for one, and I'm not inclined to do that.
https://www.seattletimes.com/seattle-news/two-attacked-by-co...
Getting old now, so walking in the woods alone is something I don't do anymore, even though things are a lot more developed nearby.