There are a bunch of mountain lions in Ohlone Wilderness. This is a bit nerve-wracking. Last time I was there I saw a bobcat chase down and kill a ground squirrel and I'm fine with those guys because they can't chase down and kill people. There was a story a few years ago that I now can't find that a few years ago a camera caught five mountain lions simultaneously feeding on a deer carcass in Palo Alto. That was more than enough to make me think twice.
Yesterday I was running on the part of the Western States trail where someone lost her life 21 years ago to a lion attack (see 1994, near Green Gate - I think). This sobering history is a large part of why these animals are interesting, and a little anxiety-inducing. And I also had the realization that no one is going to take me up on my bet that mountain lions will return to my home state of Pennsylvania by 2025. I mean they're already in Connecticut again for crying out loud, with tracking information showing that it walked from South Dakota (it wasn't captured and released by some wise guy).
(Note: if every mountain lion sighting by someone's brother-in-law while he was hunting or aunt on her patio was genuine, PA and many other states would be bursting at the seams with them. Verifiable photograph or DNA evidence, or no dice.)