Why Did The Mountain Lion Cross The Freeway? To Breed
In Los Angeles' Griffith Park, there is a mountain lion known as the "Hollywood Lion."
The big cat — known as P22 to ecologists — somehow made it across two very busy freeways to get there. Mountain lions like solitude, but if P22 wants to find a mate and have some cubs, he'll have to risk his life again in Los Angeles traffic.
P22's dilemma is one faced by an entire population of mountain lions along the 101 Freeway, less than 30 miles away from Griffith Park. The freeway slices right across the wilderness in this stretch of the Santa Monica Mountains.
"No one in 1950 was thinking about getting wildlife across roads when the freeway was built," says Seth Riley, National Park Service wildlife ecologist. "So not only do you have the freeway but you have intense development all along it. It's basically a big development corridor."
That's isolated the mountain lion population here, trapping them between the freeway and the ocean. That, in turn, has led to severe inbreeding, which could mean the end of the group.
Riley says a similar situation threatened the Florida panther, also surrounded by encroaching human development.
"They got down to 30 animals; they had even lower genetic diversity than we're seeing here," he says. Riley says they had holes in the heart, disease issues and major reproductive problems like sterile males.
A Dangerous Crossing
Riley and his colleague want the lions in the Santa Monica Mountains to avoid that fate. They track a number of GPS-tagged mountain lions on both sides of the freeway to monitor the populations. When a male lion from the north named P12 crossed the freeway to join the isolated Santa Monica cats, the ecologists felt like popping some champagne.
"He came from the north and had a lot of genetic material that was new to the Santa Monica Mountains," he says. "Fortunately not only did he survive [the crossing] but he then became a dominant breeding male ... and had many offspring and continues to have offspring."
But unfortunately, one new cat can't fix the inbreeding problem, as P12 eventually proved to Riley and his colleagues.
"The bad news is he has mated ... definitely at least once with his daughter," Riley says.
Walking along the freeway, it's easy to see why more lions don't make the crossing. It's actually kind of amazing that any lions make it across. It's not just the freeway that's a barrier. There are structures, walls and fencing on both sides; it's just about impossible for anyone, including people, to get through.
Other lions have tried, but they weren't as lucky as P12. One that was hit by a car, Riley says, might have initially made it across the traffic — but got turned around at a retaining wall and was struck going back across the freeway.
One Solution: A Wildlife Overpass
Ecologists in Florida solved their inbreeding problem by transplanting cats from distant populations. But ecologists in California think there's a simpler, natural solution that takes advantage of the population of mountain lions literally right across the street.
"Our real hope is to have an overpass across 101," Riley says.
Wildlife overpasses have been built successfully in Montana, Canada and the Netherlands. They're wide bridges planted with grass, trees and other vegetation. For motorists, it might look like any other regular bridge except for the vegetation growing on it.
"It's pretty remarkable," says Barbara Marquez, senior environmental planner for the California Department of Transportation. "It's an extension of the habitat from one side to another."
From the air, it would look like a patch of wilderness was crossing the freeway, just as the freeway crosses the wilderness everywhere else. Marquez says the overpass won't just be for lions; the plant cover will benefit a lot of other species that want to cross — including people.
"This wildlife overcrossing would connect the trail from one side to another, so pedestrians would be allowed to use it as well," she says. "It would definitely be innovative, because there's nothing like that here in California."
Marquez declined to put a price tag on the overpass because it's still in the planning stages, and the cost depends a lot on the size and scope. Wildlife overpasses in Canada have cost just a few million dollars, though some in the U.S. are projected to cost much more.
Seth Riley thinks that the overpass would have benefits that can't be measured in dollars.
"It's expensive, it's gonna take some time, but I think it would be an amazing statement about wildlife and conservation in the second-largest metropolitan area in the country," Riley says. "Everyone that would drive that freeway would see, 'Wow, they put something over this freeway specifically for wildlife.' "
Despite public and political support, the National Park Service and the state's transportation agencies have spent more than a decade trying to fund the project. And right now, funding for infrastructure is tight. The federal government recently denied an application for a $2 million transportation grant to pay for part of the overpass.
But ecologists and conservation activists aren't giving up. They're working with local agencies and trying to raise support and money from the private sector.
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Transcript
ARUN RATH: You may have heard of the Hollywood Lion, the mountain lion that lives in Griffith Park, right here in the city of Los Angeles. The big cat, known as P22 to ecologists, somehow made it across two very busy freeways to get there. Mountain lions like solitude, but if P22 wants to find a mate and have some cubs, he'll have to risk his life again in L.A. traffic.
And P22's dilemma is faced by an entire population of mountain lions just a little ways up the freeway.
(SOUNDBITE OF GRASS CRUNCHING)
RATH: I'm walking along the 101 Freeway with Seth Riley, wildlife ecologist for the National Park Service. The freeway slices right across the wilderness in this stretch of the Santa Monica Mountains.
SETH RILEY: You know, no one in 1950 was thinking about getting wildlife across roads when the freeway was built. And so not only do you have the freeway, but you have intense development all along it. It's basically a big development corridor.
RATH: That isolated the mountain lion population here, trapping them between the freeway and the ocean. That's led to severe inbreeding, which could mean the end of the group.
Riley says a similar situation threatened the Florida panther, also surrounded by encroaching human development.
RILEY: They got down to under 30 animals. And they had even lower genetic diversity than we're seeing here. So they had holes in the heart - this atrial septa. They had males where one or both testes didn't descend. And if both didn't descend, they were sterile basically. And they had major reproductive problems. They had disease issues.
RATH: Riley and his colleagues want the lions here in the Santa Monica Mountains to avoid that fate. They track a number of GPS-tagged mountain lions on both sides of the freeway to monitor the populations. When a male lion from the north, this one named P12, crossed the freeway to join the isolated Santa Monica cats, the ecologists felt like popping the champagne.
RILEY: He came from the north and had a lot of genetic material that was new to the Santa Monica Mountains. Now if he had crossed and not survived, it wouldn't have done any good. But fortunately not only did he survive, but he then became a dominant breeding male in the Santa Monica Mountains and had many offspring and continues to have offspring actually.
RATH: But unfortunately, just one new cat can't fix the inbreeding problem, as P12 eventually proved to Riley and his colleagues.
RILEY: So that's the good news. Although a little bit of the bad news is he has also mated probably repeatedly definitely at least once with his daughter. And they probably don't know. He probably doesn't know it's his daughter. He's just mating with whatever females he can find. The males don't participate in the taking-care of the offspring at all. But that kind of very close inbreeding between fathers and daughters is not good for the genetic diversity.
RATH: Walking along the freeway here, it's easy to see why more lions don't make the crossing. It's actually kind of amazing that P12 made it across. It's not just the freeway. There are structures, walls, fencing on both sides. It's just about impossible for us to get through.
RILEY: All right. That wasn't too bad, right?
(LAUGHTER)
RATH: Other lions have tried, but they weren't as lucky as P12. One met his end right along this stretch of road.
RILEY: What may have happened - again, we don't know for sure but - is that he got across the freeway, ran into this wall and couldn't keep going and then got confused or tried to go back and ended up getting hit by a car.
RATH: Ecologists in Florida solved their inbreeding problem by transplanting cats from distant populations. But ecologists here think there's a simpler, natural solution with a population of cats literally right across the street.
RILEY: Our real hope is to have an overpass across 101 here. It would connect that ridge coming down on the north side and then come down on the south side to natural area, which is the critical thing.
RATH: A wildlife overpass - they've been built successfully in Montana, Canada and the Netherlands. They're quite wide and planted with grass and trees and other vegetation. Barbara Marquez is senior environmental planner for the California Department of Transportation.
BARBARA MARQUEZ: You know, from the side view as a motorist going down the 101, it might not look very different from a regular bridge of the same type of size, except for the fact that there would be vegetation growing on it.
RATH: From the air, it would look like a patch of wilderness were crossing the freeway, just as the freeway crosses the wilderness everywhere else. Marquez says the overpass wouldn't just be for lions. The plant cover will benefit a lot of species that want to cross, including the two-legged variety.
MARQUEZ: So this wildlife overcrossing would connect the trail from one side to the other, so pedestrians would be allowed to use it as well. And it would definitely be innovative, because there's nothing like that here in California.
RATH: Marquez declined to put a price tag on the overpass because it's still in the planning stages. The cost depends a lot on the size and scope. Wildlife overpasses in Canada have cost just a few million dollars, though some in the U.S. are projected to cost much more.
But Seth Riley thinks that the overpass would have benefits that can't be measured in dollars.
RILEY: It's expensive. It's going to take some time, but I think it would be an amazing statement about wildlife and conservation in the second-largest metropolitan area in the country and one of the largest in the world to put a crossing, especially an overpass that everyone would see. You know, everyone that would drive that freeway would see, wow, they put something over this freeway for - specifically for wildlife.
RATH: Despite public and political support, the National Park Service and the state's transportation agencies have spent more than a decade trying to fund the project. And right now, funding for infrastructure is tight. The federal government recently denied an application for a $2 million transportation grant to pay for part of the overpass.
But ecologists and conservation activists aren't giving up. They're working with local agencies and trying to raise support and money from the private sector. Transcript provided by NPR, Copyright NPR.
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