by Hayley Smith

It’s 4:00 in the morning. The mountain air is cool and dark, save for the headlights of cars rushing by. A four-year-old mountain lion looks across a ten-lane highway at the scrubby brushland on the other side, and he decides to take his chance.

He loses.

On September 7, 2019, one of LA’s most beloved mountain lions was killed trying to cross the 101 freeway. GPS readings indicate that the lion, known as P-61, was between Bel Air Crest Road and the Sepulveda Boulevard underpass at the time of the accident—just a few miles from the site of a proposed wildlife bridge that could have saved his life.

“The last hope we have”

P-61 is one of 19 mountain lions who have been killed trying to cross Los Angeles freeways since 2002, the year the National Wildlife Federation began tracking their movements. It’s not a sense of recklessness or adventure that drives these lions to tempt fate—it is an act of desperation, a risk taken only because staying put is less tenable than trying to leave. Trapped by freeways, LA’s mountain lions have become geographically isolated and genetically compromised. Experts estimate that there are 50 years left before they are completely eradicated. Unless, of course, human beings intervene. 

Rendering of the LA wildlife crossing.
Photo: Santa Monica Mountains Resource Conservation

“P-61’s death was a tragic yet really on-point example of what is harming these cats,” said Beth Pratt, director of the National Wildlife Federation in California. “These freeways are blocking their escape routes. They can’t get out, and new blood can’t get in.”

Pratt is one of the key figures in the push to build a wildlife crossing in Los Angeles. Wildlife crossings—traffic-spanning bridges designed to blend in with their natural surroundings—have proven remarkably effective in reducing the deaths of animals around the country. But Pratt, along with a core team of scientists, engineers and wildlife experts, isn’t recommending just another bridge. When completed, this 200-foot-high bridge will span ten lanes of the 101 freeway, making it the largest wildlife crossing in the world.  

In addition to its record-breaking size and scope, the LA wildlife bridge will also mark the first time the concept has been attempted in such an urbanized setting. Los Angeles is one of only two megacities in the world with big cats living within city limits (the other is Mumbai), but busy freeways and rapid development throughout the area have left mountain lions and other wild animals stranded on small “islands” with no way to escape from predation or breed with other groups. The proposed location of LA’s bridge, at Liberty Canyon in Agoura Hills, will create a safe link between the Santa Monica Mountains to the south and the Simi Hills and Santa Susana Mountains to the north.

 “This critical connection is the last hope we have for linking this isolated population of mountain lions to the rest,” Pratt said

“Game Over”

A wildlife bridge is about more than safe crossing, though. According to the National Parks Service, roadkill is only the second leading cause of death for LA’s mountain lions. The first cause is something known as intraspecific strife—essentially, mountain lions killing other mountain lions.

By nature, mountain lions are territorial and need room to roam. By removing their ability to move freely, LA’s highway system is forcing lions to confront one another much more often than they would in the wild. “These males are trying to do what is innate to them,” said Justin Dellinger, senior mountain lion researcher at the California Department of Fish and Wildlife. “But considering they’re living on an island, they can’t disperse. They can’t go set up a new home range and procreate.” 

A mountian lion carcass on Malibu Canyon Road.
Photo: National Park Service

The problem of procreation is another one of the greatest threats facing LA’s lions. Because their habitats are so limited, the lions are inbreeding at a much higher rate than is typical in the wild. The genetic diversity of these lions is some of the lowest ever observed. 

Dellinger explains that in wild mountain lion populations, young males typically leave their parents at one or two years of age and travel long distances to set up a new life. “They’re the ones that spread the genetics around,” he said. But if lions are locked into a small habitat, as they are in LA, they often end up breeding with one another. In the span of six years, Dellinger said, a male lion could breed with his daughter and then his “daughter-granddaughter” several times. By the time he is replaced by a new dominant male, that new male could very well be his son or “son-grandson,” who will continue that same cycle.

“If you’re living on an island and your options are reduced, then there’s only so many times, genetically speaking, that you can procreate with relatives before things start to go bad,” Dellinger said, emphasizing that too much inbreeding will lead to disease and birth defects in a process called genetic collapse. “Their genetic material is going to be too closely related that they’re not going to be able to sustainably breed anymore,” he said. “They are going to go extinct.” 

Although current estimates say it will take about 50 years before this genetic collapse occurs, Pratt says that that number is actually a conservative estimate. She says there are only ten or twelve cats left in the entire area between Griffith Park, Ventura, Malibu and the 101 freeway, and that if you lose even one to poaching, roadkill or intraspecific strife, it will significantly reduce the time they have left.

“One year we lost four cats,” Pratt said. “You start taking them out and it becomes a less sustainable population much sooner. Game over comes much sooner than 50 years.”

Could you run across this?

This footage was taken at the site of the future wildlife crossing over the 101 Freeway. Many lions have tried—and failed—to cross all ten lanes in the past. The speed limit on this stretch of highway is 65mph.

If video does not play, click here.

“It's a No-Brainer”

Given the geographic and genetic challenges facing LA’s lions, the core team says it is of great importance that the wildlife crossing be constructed as soon as possible. The massive scope of the project means that’s easier said than done: the bridge is expected to cost $87 million dollars and will take up to two years to complete.

“When I first heard about it, I didn’t know what to think,” said Sheik Moinuddin, the CalTrans engineer who is overseeing the project. “All I knew was that it’s a unique project, and I wanted to be project manager.”

“The Santa Monica mountains are flanked on all sides by nearly impenetrable forces: miles of ocean or miles of high speed freeway. Welcome to puma prison.”

-National Park Service

A team of experts studied topography and wildlife patterns at ten possible locations before selecting the site. The land is currently owned by the Santa Monica Mountains Conservancy, and nearly 80% of the funding is expected to come from private donations. Moinuddin says that he didn’t comprehend just how special the project was until the first time he saw it presented in a community meeting. “I would say 99% supported the project,” he said. “This was one of the very first of my projects that didn’t have any opposition.” 

Pratt seconds this. “I’ve worked on public projects my whole career, and usually it’s a 50/50 split at public meetings,” she said.

“I knew something was going on when nobody stopped us or talked in opposition to it. It’s astonishing. It just doesn’t happen that way.”

Both Pratt and Moinuddin attribute a large segment of the project’s support to its tangibility. Unlike more abstract community issues like homelessness or climate change, this wildlife crossing will be a visible, concrete structure that people will actually know is working. “This is something we know we can solve,” Pratt said. “We know how to fix it, and it’s very logical: you put this here, and the wildlife will live.”

“It’s a no-brainer,” Moinuddin said.

P-22 caught on camera in the Hollywood Hills.

Source: Griffith Park Trail Cam

“Science and Story”

There’s one additional reason the wildlife crossing has full community support, and it has nothing to do with science, engineering or design. It has to do with Angelinos’ emotional connection to the lions, and for that, Pratt gets much of the credit.

“I’ve always approached this as building a movement, and I think that’s really paid off,” she said. The public awareness campaign around LA’s mountain lions is one that would leave even the most efficient marketing team in awe. There are clothing lines and hip hop songs  and letters from school children to P-22, a handsome male cat who Pratt says has become the “poster-lion” for the movement. P-22 is so beloved that there’s even an annual festival in his honor in Griffith Park.

Pratt, who has a large P-22 tattoo on her arm, runs a Facebook page for the lion and is often seen carrying life-sized cardboard cutouts of the animals. She says her colleagues found her unconventional tactics embarrassing at first, but once they saw how people were connecting with the lions, they all bought in. Now they carry cardboard cutouts right next to her.

“You need the public to value wildlife, and it’s not going to happen because you published a scientific paper,” she said. “It’s going to happen because you captured their imagination.” Pratt also says that traditional scientists are taught to keep their distance and avoid naming or anthropomorphizing the animals. “I think that has really hurt the environmental movement,” she said. “Distancing ourselves doesn’t mean we’re doing better science.”

Pratt calls this approach “Science and Story,” and she says it has been key to the project’s success. She now receives phone calls from other wildlife managers around the country asking how she did it. “The LA times even has a cougar beat!” she laughs. The paper has published more than 30 stories about LA’s mountain lions in 2019 alone.  

 “It’s not about telling people how to feel, it’s about honoring the different ways in which people connect with nature,” Pratt said, adding that this connection, in turn, will make it that much easier next time they have a major wildlife project to push through.

Liberty for All

A scientific study of 10 possible locations determined that Liberty Canyon is the best place best place to provide connectivity for a range of species.

“A Natural Extension”

The plans for LA’s wildlife crossing are now entering final stages. If all stays on track, it will break ground in 2021. Although Moinuddin estimates that it will take up to two years to complete, he says that 101 freeway users will face minimal interruptions or lane closures. He and Dellinger, the mountain lion researcher, both emphasize that although the lions are the public face of the project, the wildlife crossing will benefit all animals and plants in the area—many of which are displaying signs of genetic isolation as well.

As for getting the mountain lions to use the bridge, no one on the core team has any concerns. According to Moinuddin, the crossing has been specifically designed to look like a natural extension of the habitat, and fencing will be put in place to help funnel the animals to the entrance.

Dellinger says that both the mortality and GPS data demonstrate that the lions are trying to leave. “They’re testing the roads and looking for ways to go,” he says. “If you put it in the right place, they’ll find it.”

In Their Own Words

LA's wildlife bridge is the result of a collaboration between scientists, activists and engineers. Here, each one explains why they feel this project is so important.

©2019 by HAYLEY SMITH