Mountain lion P-55 crosses the 101 freeway—it’s a rare achievement

A young, male mountain lion known as P-55 has successfully made a “rare” crossing of the 101 freeway, National Parks Service researchers announced today. P-55 was previously roving the western part of the Santa Monica Mountains. Now he’s “roaming the Santa Susana Mountains” along the northern edge of the Valley.

P-55 is wearing a GPS tracking collar, so researchers also know he has crossed highways 118 and 23. The parks service says the mountain lion crossed the 101 near Thousand Oaks. He did so shortly after he was captured on video nearly falling into a Newbury Park hot tub.

Crossing the freeway is a considerable accomplishment for P-55 because most lions come up to the edge of the freeway, then turn around, says Seth Riley, a wildlife ecologist at Santa Monica Mountains National Recreation Area.

P-55's move deeper into the Valley is only the fourth successful crossing of the 101 freeway since 2002, when the parks service began keeping track.

The impassability of the freeways around the mountain lions’ Santa Monica Mountains territory is a significant obstacle, especially for male cougars. Freeways confine lions to an area where there are already dominant males, which can lead to fatal conflicts. Most young male lions in the area don’t live past two years old.

Being hemmed in has also led to inbreeding. Unless the genetic diversity of the big cats improves, extinction is a possibility, perhaps in as little as 50 years.

A wildlife overpass, which would allow for animals to safely cross the 101 freeway at Calabasas’s Liberty Canyon, has been in the works for years. Project backers want to see the project open by 2021.

• Because of freeways, LA's inbred mountain lions might be extinct in 50 years [Curbed LA]