A scientific review of records on attacks by cougars on humans in the United States and Canada from 1890 through 1990 indicated there were 53 attacks during this period, of which ten were fatal. Since 1990 there have been only three more verified fatal attacks in the United States, one in Colorado and two in California. In California, mountain lion populations have grown. In 1920, a rough estimate put the cougar population at 600. Today's population estimate ranges between 4,000 to 6,000.
Natural enemies are large predators, such as, bears, lions, and at one time in California, wolves.
They also fall victim to accidents , disease, road hazards, and people. Generally, mountain lions are calm, quiet, and elusive. But now that people and mountain lions occupy so much of the same geographical areas in California, encounters are expected to increase. The potential for being killed by a mountain lion is quite low. There is a far greater risk, for example, of being struck by lightning than of being attacked by a cougar.