It’s not quite like mice jumping off a burning ship, but the analogy isn’t too far off—as the population of mountain lions in the Santa Monica Mountains becomes more inbred and all the available territories are taken by other mountain lions, the young often have no choice but to risk their lives by trying to cross the freeways in search of mates and territory.

On Sept. 4, the National Park Service (NPS) announced mountain lion P-65 made history by being the second radio-collared female ever to cross the Ventura (101) Freeway.  Park officials said the young lion was believed to have run across the roadway, since no images of her were captured by cameras in an underground culvert there that male P-64 used several times.

The data from P-65’s radio collar indicated she crossed the freeway near Liberty Canyon in Agoura Hills on August 21 between midnight and 2 a.m., moving north to the Simi Hills. 

The only other female to cross the 101 was P-33, who crossed near Camarillo in March 2015 and eventually settled in Los Padres National Forest.

The place P-65 chose to cross is notable, as it’s already the site where a landscaped wildlife crossing bridge will be built starting in 2022. Supporters were quick to point out that her crossing at that spot appeared to be further proof that this is the right spot to put the bridge. NPS scientists warn mountain lions in the Santa Monica and Santa Ana mountains risk extinction in the next 50 years from inbreeding; one of the main reasons for building the bridge is to help increase their genetic diversity. 

P-65 is a young female that was one of 11 mountain lions NPS biologists were tracking in or around the fire perimeter when the Woolsey Fire broke out on Nov. 9, 2018. She managed to survive the fire, but her entire home range was in the burn area and scientists were interested to learn how or if she would change her movements as a result. 

As of early 2019, she continued to spend all of her time within the fire perimeter, indicating to the biologists that she was, “Likely finding unburned portions of land and opportunities to prey on mule deer in the area.” She earned the nickname “Coastal Cat” for her inclination to stick to the coastal areas west of Las Virgenes Road. 

Earlier this year, she was recaptured to replace her radio collar and researchers reported she looked healthy and weighed 85 pounds. (An adult female mountain lion weighs 80 to 130 pounds.) P-65 was first captured and collared in the central portion of the Santa Monica Mountains in March 2018.

Unfortunately, not all attempted highway crossings by the local big cats are successful. Last Saturday, Ranger Ana Beatriz of the NPS reported that mountain lion P-61 was struck and killed on the 405 Freeway in the Sepulveda Pass on Sept. 7, around 4 a.m. His final GPS point indicated he was between Bel Air Crest Road and the Sepulveda Boulevard underpass.

She wrote, “California Highway Patrol was initially alerted and moved P-61 out of traffic. City of Los Angeles Animal Control officers then retrieved his body and the radio-collar and notified both California Department of Fish and Wildlife personnel researchers of the Santa Monica Mountains National Recreation Area.”

To the amazement of researchers, the four-year-old cat successfully crossed the daunting 10-lane freeway near the Sepulveda Pass area just a couple months ago. Scientists aren’t exactly sure why P-61 decided to try to cross back again, but they have a pretty good guess. Over the last few years, remote cameras have photographed an uncollared male mountain lion living in the area P-61 crossed into. If the two were fighting and competing for territory, P-61 must have decided his survival depended on leaving again, the NPS indicated: “Based on his GPS points, he’d been staying close to the eastern edge of the 405 more recently.” 

P-61 made history when he was the first and only collared mountain lion in the 17-year history of local mountain lion research to successfully cross the 405 Freeway. Two others had tried—young male P-18 was hit by a car in 2011 in the Sepulveda Pass area as well as another uncollared male in 2009. 

For more information on the wildlife bridge or to make a donation, go to the Save LA Cougars website or contact 

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