The animal died at the scene of the collision, which was reported at about 7:35 a.m. in the 33200 block of Pacific Coast Highway, according to the Los Angeles County Sheriff's Department.
The motorist did not stop.
"P-104, a subadult male mountain lion, was killed by a car on PCH today. He was the most recent cat to be captured as part of our puma study,'' the Santa Monica Mountains National Recreation Area tweeted. "He is the 25th cat & 8th collared study cat to be killed by a car and the first we've documented being hit & killed by a car on PCH.''
Animal control personnel were sent to the scene to remove the fatally injured animal, the sheriff's department reported. The roadway remained open.
J.P. Rose, a senior attorney with the Center for Biological Diversity, said the lion's death is a reminder that "our roads are death traps for local mountain lions and other wildlife.''
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Rose urged the state Legislature pass legislation sponsored by the center that would build 10 wildlife crossings per year on state roads, and to identify roadkill hotspots.
"Wildlife crossings have to be a top priority before it's too late and we lose the Santa Monica Mountains puma population forever,'' Rose said.