Los Angeles is one of only two megacities in the world (the other is Mumbai) that have big cats living within the city limits. In a place more often associated with freeways and traffic, the fact that the city can support such large-ranging animals is a testament to the quality of open space and the habitat connectivity that still remains.
The National Park Service has been studying how mountain lions survive in an increasingly fragmented and urbanized landscape since 2002. Since then, researchers have monitored more than 100 mountain lions in and around the Santa Monica Mountains north of Los Angeles. GPS radio-collars provide detailed information about the animals' ecology and behavior.
Big Cats, Big Challenges
The good news for mountain lions in and around the Santa Monica Mountains is that the population is stable, with healthy rates of survival and reproduction.
The long-term survival of mountain lions in this region, however, is threatened by a number of factors, none more significant than the loss and fragmentation of habitat by roads and development. This leads not only to deaths from vehicle collisions, but also multiple cases of first-order inbreeding because animals are not able to disperse in and out of the area. Genetic analyses indicate that lions in the Santa Monica Mountains, along with a similarly isolated population in the Santa Ana Mountains south of LA, have the lowest levels of genetic diversity ever documented in the West. The only population with lower levels was in south Florida in the mid-90’s when Florida panthers were on their way to extinction.
Another major threat to the species is the widespread presence of anticoagulant rodenticides, commonly known as rat poisons, in the environment. Twenty-eight out of 29 mountain lions tested in the study have tested positive for one or more anticoagulant compounds and seven have died from anticoagulant rodenticide poisoning (as of November 2021).
A leading cause of death for mountain lions in this area is from vehicle strikes. We have documented at least 32 mountain lions killed by vehicles in our study area since 2002. Another major cause of death for mountain lions in the study is intraspecific strife, or mountain lions killing other mountain lions. Though common in other populations, this rate may be exacerbated by the fact that mountain lions are basically trapped on an island of habitat, surrounded by freeways, development, and the Pacific Ocean.
Restoring Habitat Connectivity
The long-term survival of a mountain lion population here depends on their ability to move between regions to maintain genetic diversity and overall population health.
A solution to address this issue -- the Wallis Annenberg Wildlife Crossing across the 101 Freeway, the biggest barrier between the Santa Monica Mountains and other large natural areas—is currently under construction by Caltrans and anticipated to open in late 2025. A private fundraising initiative, Save LA Cougars, raised money for the effort.
This wildlife crossing allow for mountain lions living north of the Santa Monica Mountains to travel into the range and for animals living south of the freeway to disperse out of the area.
From the very first study animal and former king of the mountains (P-001), to the first mountain lion documented to cross from north of the 101 Freeway to the south (P-012), to the famous mountain lion who lived in Griffith Park (P-022), each of these animals have helped us better understand the challenges and also the opportunities for keeping the population healthy and viable.
More than 200 high-resolution photos of mountain lions are available for download at our Flickr site. Several videos and maps are also available.
All maps and photos are part of the public domain (no need to request permission prior to using, though attribution to "National Park Service" is appreciated).
Mountain lions are solitary, elusive animals and sightings are extremely rare. Based on more than 250,000 GPS locations collected since 2002, it is clear that mountain lions prefer natural areas and attempt to avoid coming in contact with humans.
If you do encounter a mountain lion, make yourself appear as large and intimidating as possible by yelling, waving your arms, and even throwing objects in the direction of the animal. Slowly back away and allow space for the mountain lion to move away. Do not turn your back and run.
The National Park Service has studied 112 mountain lions in and around the Santa Monica Mountains.
We estimate a population of around 10-15 adult and subadult mountain lions (not including kittens) live in the Santa Monica Mountains at any given time.
The major causes of death among study animals are vehicle collisions, rodenticide poisoning, and intraspecific strife (mountain lions killing other mountain lions).
A total of 32 mountain lions have been struck and killed by vehicles in the study area since 2002.
A typical home range is around 150 square miles for adult males and 50 square miles for adult females in our region.
Mountain lions typically eat about one deer per week, along with other smaller prey as the opportunity arises. NPS researchers have analyzed more than 700 kills, of which 87% were mule deer (the second-most common prey was coyotes and then raccoons).
28 of 29 mountain lions have tested positive for exposure to one or more anticoagulant rodenticides (rat poison) and seven have died directly of poisoning. *as of December 19, 2022
Huffmeyer, A., J.A. Sikich, T.W. Vickers, S.P.D. Riley, and R.K. Wayne. 2021. First reproductive signs of inbreeding depression in Southern California male mountain lions (Puma concolor). Theriogenology, In press
Riley, S.P.D., J.A. Sikich, and J.F. Benson. 2021. Big Cats in the Big City: Spatial Ecology of Mountain Lions in Greater Los Angeles. Journal of Wildlife Management 85(8): 1527-1542.
Benson, J.F., H.N. Abernathy, J.A. Sikich, and S.P.D. Riley. 2021. Mountain lions reduce movement, increase efficiency during the Covid-19 shutdown. Ecological Solutions and Evidence 2: 1-14.
Benson, J. F., J. A. Sikich, and S. P. D. Riley. 2020. Survival and competing mortality risks of mountain lions in a major metropolitan area. Biological Conservation 241:108294.
Benson, J.F., P.J. Mahoney, T.W. Vickers, J.A. Sikich, P. Beier, S.P.D. Riley, H.B. Ernest, and, W. M. Boyce. 2019. Extinction vortex dynamics of top predators isolated by urbanization. Ecological Applications e01868.
Gustafson, K.D., R.B. Gagne, T.W. Vickers, S.P.D. Riley, C.C. Wilmers, V.C. Bleich, B.M. Pierce, M. Kenyon, T.L. Drazenovich, J.A. Sikich, W.M. Boyce, and H.B. Ernest. 2019. Genetic source–sink dynamics among naturally structured and anthropogenically fragmented puma populations. Conservation Genetics 20:215–227.
Saremi F. Nedda, M.A. Supple, A. Byrne, J. A. Cahill, L.L. Coutinho, L. Dalen, H.V. Figueiro, W.E. Johnson, H.J. Milne, S.J. O’Brien, B. O’Connell, D.P. Onorato, S.P.D. Riley, J.A. Sikich, D.R. Stahler, P.M.S. Villela, C. Vollmers, R.K. Wayne, E. Eizirik, R.B. Corbett-Detig, R.E. Green, C.C. Wilmers, B. Shapiro. 2019. Puma genomes from North and South America provide insights into the genomic consequences of inbreeding. Nature Communications 10, Article number: 4769.
Benson, J. F., P. J. Mahoney, J. A. Sikich, L. E. K. Serieys, J. P. Pollinger, H. B. Ernest, and S. P. D. Riley. 2016. Interactions between demography, genetics, and landscape connectivity increase extinction probability for a small population of large carnivores in a major metropolitan area. Proceedings of the Royal Society B 283:20160957
Benson, J. F., J. A. Sikich, and S. P. D. Riley. 2016. Individual and population level resource selection patterns of mountain lions preying on mule deer along an urban-wildland gradient. PLoS ONE 11(7):e0158006. doi:10.1371/journal.pone.0158006.
Riley, S. P. D., J. L. Brown, J. A. Sikich, C. A. Schoonmaker, and E. E. Boydston. 2015. Wildlife friendly roads: the impacts of roads on wildlife in urban areas and potential remedies. In B. McCleery, C. Moorman, and N. Peterson, editors, Urban Wildlife Science: Theory and Practice. Elsevier Press.
Riley, S. P. D., L. E. K. Serieys, J. P. Pollinger, J. A. Sikich, L. Dalbeck, R. K. Wayne, and H. B. Ernest. 2014. Individual behavior dominate the dynamics of an urban mountain lion population isolated by roads. Current Biology 24:1989-1994.
Bartos, M, S. Dao, D. Douk, S. Falzone, E. Gumerlock, S. Hoekstra, K. Kelly-Reif, D. Mori, C. Tang, C. Vasquez, J. Ward, S. Young, A. T. Morzillo, S. P. D. Riley, and T. Longcore. 2012. Use of Anticoagulant Rodenticides in Single-Family Neighborhoods Along an Urban-Wildland Interface in California. Cities and the Environment (CATE) 4: Article 12.
Moriarty, J. G., L. Whited, J. A. Sikich, S. P. D. Riley. 2012. Use of Intraperitoneal Radiotransmitters to Study Mountain Lion (Puma concolor) Kittens. Wildlife Society Bulletin 36(1): 161-166
Moriarty, J. G., S. P. D. Riley S, L. E. K. Serieys, J. A. Sikich, C. M. Schoonmaker, and R. H. Poppenga. 2012. Exposure of wildlife to anticoagulant rodenticides at Santa Monica Mountains National Recreation Area: From mountain lions to rodents. Pp. 144-148 In R. Timm, editor, Proceedings of the 25th Vertebrate Pest Conference. University of California, Davis.
Gehrt, S. D., S. P. D. Riley, and B. L. Cypher. 2010. Urban Carnivores: Ecology, Conflict, and Conservation. Johns Hopkins University Press. 285 pp.
Riley, S. P. D., J. Pollinger, R. K. Wayne, R. M. Sauvajot, E. C. York, and T. K. Fuller. 2006. A southern California freeway in a physical and social barrier to gene flow in carnivores. Molecular Ecology 15:1733-1741.
Ng., S., R. M. Sauvajot, J. Dole, S. P. D. Riley, and T. Valone. 2004. Use of freeway undercrossings by wildlife in a fragmented urban landscape in southern California. Biological Conservation 115:499-507.