The early September death of a female puma along the highway connecting Riverside and Orange counties in the Santa Ana Mountains has wildlife advocates calling for more protection for California’s vulnerable mountain lion population.
Officials from the California Carnivores Program at the UC Davis School of Veterinary Medicine/Drayer Wildlife Health Center confirmed Monday, Sept. 15, that a 3-year-old female puma, called ‘F390,’ was killed along Highway 74, also known as the Ortega Highway.
The animal was found dead along the highway by the San Juan Creek trail, on Thursday, Sept. 4, Program Director Fernando Nájera said. OC Parks officials found the body, with its identifying collar destroyed.
“We are deeply saddened to share that mountain lion F390, one of the collared lions in our study, was recently killed by a vehicle strike on Highway 74,” a Sept. 5 Instagram post announcing the lion’s death states. “At just 3 years old, F390 was raising her first litter … she had successfully crossed this busy highway many times before, but this time, traffic proved fatal. Her loss is a stark reminder of the risks carnivores face as their habitats overlap with our roads and communities.”
The mountain lion had been collared since February 2024, Nájera said. She had been spotted across the wilds of the Santa Ana Mountains, with her collar tracking a wide range of her whereabouts, about 16 square kilometers of the forest areas.
“It’s been devastating news,” Nájera said.
The California Carnivores Program, formed in 2001 originally as the California Mountain Lion Project, focuses on mountain lion conservation and protection, and has since expanded to include other carnivore species, such as wolves and bobcats. The program tracks mountain lion’s habitat use and movement, including the species’ overall health and lifestyle, living among urban development such as roads and highways.
“F390” was raising a male and female cub, who are now about 14 months old, officials said. There was no information on the whereabouts of the litter, who were not collared/tracked by the program.
“In only a few more months, she would have guided her young to leave her care and be independent,” officials wrote online.
Nájera said that four pumas/mountain lions are currently being tracked in Southern California through the Carnivores Program. The Santa Ana Mountains has a fairly large population, he said, though specific numbers are unknown.
The collar around these mountain lions helps to track whereabouts, and can report specific health data, biometrics, human interactions, their kill history and productivity, mortality, recovery, and “a wealth of information we can use to create better, informed decisions on their health,” Nájera said.
“If you protect mountain lions, you’re going to protect a wide range of species that live among them, and the habitat where they live … it’s vital to keep the co-existing balance to the region,” he said. “Mountain lions are very attractive to the public, and their existence highlights the importance of their conservation.”
“We know that mountain lions are going to be crossing roads in this area, and it’s almost impossible to try to avoid — the landscape is so fragmented. They live in a matrix of roads. So we need to promote more areas where animals can cross the roads more safely,” Najera said. “Losing a mountain lion is probably also putting a human life in danger.”
Through tracking their whereabouts, Najera hopes they can gather as much “finescale movement” and data to learn the best spots “to create mitigation measures” and prevent such deaths.
Tiffany Yap, a senior scientist at the nationwide Center for Biological Diversity, which advocates for state wildlife protections and removing barriers to wildlife movement, called F390’s death a “gut punch” because, as a young mother, the animal was raising two cubs “who were just months away from becoming independent.”
“This struggling Santa Ana Mountains puma population can’t afford to lose another member,” Yap said. “Roads and development have constrained their habitat to a tipping point. Our best hope is to invest in more wildlife crossings and avoid poorly planned developments that cut through their home turf.”
In some places across Southern California, wildlife crossings and fences have been used along freeways and roadways to keep animals safe.
This is a developing story. Check back for updates.