The man was not able to tell investigators what he was attacked by, but officials say but officials say his injuries indicate he was mauled by a big cat.
According to ABC7 Los Angeles, the man was transported to a nearby hospital with lacerations, puncture wounds and bite marks at the base of the skull.
"We are about 99 percent that it was a lion," Foy said. "The conclusion is based solely on the victim's injuries and the extent of the injuries."
The man was recovering at a hospital after undergoing emergency surgery.
"He's lucky to be alive," Foy said.
Crews were searching overnight for any signs of the mountain lion. Baited traps were also set, but investigators have yet to find the animal. Foy said mountain lions typically return to the scene of a kill 24 to 48 hours later so they can continue feeding.
Officials said they collected DNA from the victim to match the lion when it is captured, and it will then be "destroyed."
Mountain lion attacks on humans are not common. Since 1986, there have been 15 confirmed attacks - with three fatalities - in the state, according to California Department of Fish and Wildlife records.
The Associated Press and our sister station, KABC-TV Los Angeles, contributed to this report.