Mountain lions and the lack of MTB buddies to ride with are why I hardly ever ride my mountain bike right now. It's only about 10 miles away from my house where the last major mountain lion vs cyclist attack happened, killing one and maiming another.
Do you know that only 3 people were killed by mountain lions in all of California in the last 50 years? You have far, far greater chances of dying of a heart attack on your road bike (roughly 1 in 1000 chance of dying in a given year, assuming that you ride 10 hours/week and your odds of dying per hour of riding are the same as the odds of a typical marathon runner).