Image showing the differences between a mountain  lion and a bobcat.Credit: CougarNetwork.net.  

What is a mountain lion?

Mountain lions are a species of wild cat found throughout the Americas.  They are the largest wild cat in western North America and are found across California. The California Department of Fish and Game estimates the current mountain lion population in California to be between 4,000-6,000 mountain lion individuals.   Although they look quite different from a bobcat (see 'Urban Carnivores' page), people often mistake bobcats for mountain lions. However, mountain lions are much larger than bobcats and are uniformly colored tawny or beige.  There can be some variation in color throughout it's range, but in Southern California, our mountain lions are a yellowish beige color. Mountain lions have a long, black-tipped tail, and small head with round ears (unlike the bobcat's pointed ears with tufts of hair).  Although young mountain lions have distinctive spots (until nearly 1 year of age), if you see a spotted cat roaming around, it is more likely a bobcat rather than a mountain lion! If you live in areas that are mountain lion habitat or utilize natural areas in the Santa Monica Mountains for recreation, you should act accordingly!  Simply because you don't see the mountain lions doesn't mean they aren't there. Reported sightings of mountain lions does not imply increased danger in a given area.  For safety tips, please visit the Mountain Lion Foundation website.  

One of the first photos of a mountain lion in the Santa Monica Mountains taken in 2002. 


Geographic distribution of the mountain lion

The mountain lion ranges from northern Canada south to the southern tip of South America, though the wild cat is extinct or very rare over much of its former range.  Mountain lions have more common names than any other species of mammal! They include include mountain lion, puma, cougar, catamount, painter and panther.  This wide variety of names reflects their historically wide geographic distribution throughout the Americas.  In fact, the mountain lion, even in its present day geographic distribution, has the largest geographic distribution of any wild cat in the world! However, mountain lions were once distributed across  the entirety of the United States. Due to human persecution and hunting, mountain lions are now found almost exclusively west of the Mississippi River, except for threatened populations of Florida Panthers. However, their populations seem to be rebounding and they and expanding their range once again. 


Are there mountain lions around Los Angeles?

The answer is YES!  People (even those people that can call the parkland their backyard) are frequently surprised to discover that mountain lions live in the Santa Monica Mountains that extend west from Ventura and east into Los Angeles- all the way to Griffith Park where the Hollywood sign is!  Mountain lions have also been studied using GPS and radio telemetry (through the use of radio-collars) by the National Park Service in the Simi Valley (Cheeseboro/Palo Comado) and Santa Susana Mountains, areas south of the 101 Freeway between the I-405 and Camarillo Springs (Point Mugu SP, Malibu Creek SP, and Topanga SP), and now even in Griffith Park just a few miles from downtown Los Angeles (read more about P22- The Hollywood Lion on his page and see video below). 


GPS data points for a mountain lion in the Santa Monica Mountains. The blue dots represent individual GPS locations, and the clusters indicate kill sites.

Diet

Mountain lions are strict, but generalist, carnivores. This means that they eat other animals that they hunt themselves, but are opportunistic in the animals they will hunt.  However, mountain lions may have a strong preference for certain prey items depending on where they live. For instance, in the Santa Monica Mountains, 94% of the mountain lion diet consists of mule deer. Other common prey species were raccoons, badgers, and coyotes. These data were gathered by examining 390 kill sites in the Santa Monica Mountains made by 15 mountain lions.

To find the kill sites, biologists rely on the radio-telemetry data gathered by the mountain lion's radiocollars.  The radiocollars are GPS-enabled and collect at specified intervals. If a mountain lion stays at a single spot feeding on a deer for several nights, when biologists examine the GPS information collected by the radiocollar, they will find clusters of points on consecutive days (see map).  Once a cluster of points is identified, biologists physically go to the location on the map and search for the mountain lion kill site.  This often occurs weeks or months after the lion has consumed what it kills and does not interfere with the behavior of the mountain lion.  If the kill site is relatively fresh, biologists might find uneaten parts of the deer, such as bones and intestines, still cached (see below for more info on 'caching').  Even for kill sites that are a year old, biologists can often find bones remaining from the kill and identify the species on which the mountain lion fed. 

A photo of a cached deer in the Santa Monica Mountains. 

A local preference for mule deer is not surprising given that it is the largest prey item available for mountain lions in southern California.  Energetically, they want to be "economic" in their prey item choices. Hunting is very energetically expensive for an animal and there is a high failure rate. So, they will generally hunt things that will have a big pay off for them calorie-wise and that may even sustain them for several days. So, mountain lions will fare better in killing large prey items that can sustain them for several days.  Depending on the size of deer that a mountain lion successfully kills and the time of year, the mountain lion can feed on the deer for around 5 days.  They tend to feed on their kills at night, eating soft organs first, such as the liver and the heart.  Once the mountain lion is done feeding for the night, it will 'cache' the kill, covering it up with dirt, leaves and brush, conceaing the deer from scavengers.  For several nights, the mountain lion will return to it's kill to feed on it staying in the general region of the kill during the day to rest.  

Santa Monica Mountains radio-collared mountain lion feeding on mule deer in the Santa Monica Mountains. The deer was cached and the lion has come back to feed. 

Locally, mountain lions have been known to kill other animals native to the Santa Monica Mountains such as coyotes, raccoons, and badgers.  They likely do not feed on these prey for multiple nights since these animals are smaller and can be quickly consumed by a carnivore the size of a mountain lion.  NPS biologists have never documented a mountain lion to kill domestic dogs or domestic cats in the study area though biologists frequently recieve complaints that this has occurred.  Local mountain lion biologists have investigated many of these complaints never finding valid evidence that mountain lions have been responsible for someone's missing pet.  Further, of the 390 kill sites investigated, all animals killed by the mountain lions were found to be animals native to the study area and the natural prey items of mountain lions.  Attacks on people's pets are more likely perpetrated by coyotes, owls, or other predatory species.

Below is a video filmed in the Santa Monica Mountain study area using a remote camera set on a mountain lion kill.  The camera filmed in 30-second increments and shows the mountain lion is coming back to a deer that it has killed on a previous night.  The mountain lion has cached it- or covered it with leaves and dirt so as to hide it from potential scavengers.  The mountain lion comes back for another night to feed on it, then re-caches the kill to save it for later.  Watch this video to learn about Santa Monica Mountains mountain lion feeding behavior! 


Movement, homeranges, and dispersal

More info coming soon!


64,848 GPS location points for 22 mountain lions. These data were collected using radio-collars placed on mountain lions. Map provided by the National Park Service. 


Threats to local mountain lions and sources of mortality

Situated near one of the largest cities in the world, wildlife that live in the Santa Monica Mountains can face some very unique challenges compared with wildlife in more remote locations. However, understanding these challenges is critical, and when thinking about conservation, examining sources of mortality for wildlife populations may be important to conservation and management plans.

A map of locations for some of the mortalities for mountain lions in the Santa Monica Mountains.   

For mountain lions studied by the National Park Service in the Santa Monica Mountains three primary sources of mortality include: 1) aggression between individuals–  2 animals may encounter each other in the mountain an then fight until one animal dies, 2) vehicle collisions, and 3) rodenticide poisoning.  Other less frequent causes of death for Los Angeles mountain lions include starvation (after being abandoned, as a kitten, by its mother), gunshot, and even one case of poaching. Sometimes if the mountain lion bodies are not found by biologists until several days after death, it can be difficult to determine the cause of death. So it is possible that mountain lions have died of other causes, such as disease, in the study area.


Mountain lion genetics in the Santa Monica Mountains

The Santa Monica Mountains is a large natural area within Greater Los Angeles that is completely isolated by urban development and the 101 Freeway to the north. Yet the Santa Monica Mountains support a mountain lion population, which, to our knowledge, is a very rare example of a large carnivore persisting within the boundaries of a megacity. National Park Service biologists studying this population have collected GPS location data from radio-collared mountain lions over a period of more than a decade. The locations of the radio-collared mountain lions indicate that freeways are a near-absolute barrier to movement. As strong barriers to movement, the freeways thus act as barriers to gene flow, or the exchange of genetic material between populations. For a small isolated population prone to inbreeding, this lack of gene flow could be problematic, threatening the long-term stability of the Santa Monica Mountains mountain lion population.

To investigate the genetic health of the Santa Monica Mountains mountain lion population and nearby populations as well, National Park Service, UCLA and UC Davis biologists worked together to genotype, or collect genetic data, on 42 mountain lions from the Santa Monica Mountains, Simi Valley, Santa Susana Mountains, and San Gabriel Mountains. To collect these data, the biologists used 54 microsatellite loci, genetic markers that are excellent tools for understanding random demographic genetic processes in populations.

The results of this genetic study were striking.  The biologists found that genetic diversity in Santa Monica Mountains mountain lions, prior to 2009, was lower than that for any population in North America except in southern Florida, where long-term inbreeding led to birth defects and reproductive failure in that mountain lion population. Biologists also documented multiple instances of father-daughter inbreeding, confirming that isolation due to freeways and small population size has led to inbreeding which has caused the low levels of genetic diversity. Using field research combined with forensic genetic techniques, biologists also documented high levels of intraspecific strife (lions attacking and often killing other lions), including the unexpected behavior of a male lion (P01) killing two of his offspring and the mother of a litter of his kittens. P01's son (P09) was also shown to have killed two of his brothers.

Using both genetic and field research techniques, biologists have found no individuals from the Santa Monica Mountains have successfully dispersed, or left the Santa Monica Mountains via crossing the 101-Freeway, to find new, unoccupied territories they could successfully establish to find new mates. Gene flow is critical for this population, which was verified when P12, a single male immigrated in 2009 into the Santa Monica Mountains, past the 101 Freeway from the Simi Valley. P12 successfully mated and substantially enhanced genetic diversity of this population, showing that a single immigration event could alter the genetic diversity of the population as a whole. However, due to continued isolation, inbreeding has continued, and so although the new genetic material P12 brought to the population helped increase genetic diversity, with time, genetic diversity will again decrease if habitat connectivity is not enhanced. The results of this study, overall, imply that individual behaviors, most likely caused by limited area and reduced opportunities to disperse, may dominate the fate of small, isolated populations of large carnivores. 


Methods to study mountain lions in the Santa Monica Mountains

The first photographic evidence of mountain lions was captured at Deer Creek and Castro Crest in the Santa Monica Mountains in 2002. 

The study of mountain lions in the Santa Monica Mountains began with the use of wildlife remote cameras to detect the presence of mountain lions in the area. National Park Service biologists placed remote cameras (that are triggered when an animal walks in front of the camera) in various locations in the Santa Monica Mountains. In 2002, biologists were rewarded with several remote camera photos of mountain lions (see map and photos above).  

Once evidence of mountain lions in the area was discovered, NPS biologists began trapping mountain lions to fit them with radio-collars in order to study their movement patterns, diet, reproduction, sources of mortality, and how these animals were being affected by urbanization. NPS biologists captured adult mountain lions using standard methods for the capture of large carnivores. 

Trapping methods include include the use of foots nares, modified to maintain the safe capture of animals, and monitored regularly to ensure than animals are not trapped in a foot snare for more than several hours.  NPS biologists also use trained hound dogs to recapture mountain lions that are already radio-collared and need their collars replaced (their batteries run out after approximately 2-years).  Finally, biologists use cage traps that when set, are also monitored frequently to ensure the safety of any captured animal. Three litters of kittens have also been hand captured at their den while their mother was away hunting, in order to collect genetic samples from the kittens and fit them with an abdominally implanted radio-transmitter. NPS biologists that trap the mountain lions are highly trained and strategic in their approach to trapping. For example, they try to avoid recapturing mountain lions when it is unnecessary.  Because multiple animals are radio-collared animals throughout mountains, biologists will close any traps in an area near a radio-collared mountain lion in order to avoid unnecessarily capturing the radio-collared lion.  This method is very effective- NPS biologists have never recaptured a mountain lion they were not targeting.  

Once animals are captured, they are safely and humanely immobilized with anesthetics by highly trained NPS biologists (or in the case of kittens, by a vet).  Once a mountain lion is sedated, biologists collect standard data on each animal such as morphological measurements (body length, animal weight, canine length, etc.).  Biologists also record the sex and estimated age all while carefully monitoring vital signs of the sedated animal to ensure the animal's safety. All animals are marked with eartags, and adults are fitted with GPS radio-collars. Blood and tissue samples are collected for genetic analysis, disease surveys, and to take measurements that evaluates the general health of each animal.  In addition to samples collected at the time of animal capture, NPS biologists also opportunistically obtain samples for genetic analysis from other mountain lions, including roadkills, animals killed as a result of control action by police or State officials, or if we find mountain lion scat (fecal matter) while doing fieldwork in the study area. 

Once an animal is fitted with a GPS-enabled radio-collar, data collection on its movement patterns begins. The collars are programmed to collect GPS locations on a variety of schedules ranging from 4-24 locations/day.  The GPS collars also have VHF beacons, or radio-transmitters with a signal frequency unique to each animal, enabling biologists to locate in real-time radio-collared individuals.  Kittens that are implanted with radio-transmitters are always located using ground triangulation. The method of ground triangulation involves first locating the radio-signal with a special receiver that can receive the unique radio-signal for each mountain lion.  Then, within approximately 15-30 minutes, biologists will use an antenna, a GPS-device, and a compass to record the direction of the radio-signal from 3 separate locations.  Because three angular directions are collected, when plotted on a map, the intersection of the three directional angles marks the location of the animal.  

 All radio-collars and radio-implants have a "mortality mode" that indicates when an animal has died. This feature of radio-collars is critical to learning about the sources of mortality for mountain lions in the Santa Monica Mountains. When an animal is alive, the collar or implants emit a beeping signal of approximately 60 beeps/minute. When an animal dies and after several hours of the animal not moving, the signal changes to approximately 120 beeps/minute. NPS biologists are then able to find and recover the dead animals as soon as possible. NPS has necropsies (the animal equivalent of an autopsy) done by the California Animal Health and Food Safety Lab (CAHFS), San Bernardino Branch. When a mountain lion is killed by another mountain lion, the signs of death include bite wounds and scratches, and can be very obvious to biologists that find the body. To determine the identity of animals involved in a fight, NPS biologists collaborate with geneticist Robert K. Wayne at UCLA to use forensic techniques to collect DNA and try to identify the other animal involved in the fight.  The biologists or the pathologists performing the necropsy will collected DNA samples from the wounds and claws of animals that had died using cotton-tipped swabs.  DNA is then extracted from these swabs using standard genetic techniques, the DNA is genotyped to construct a DNA "fingerprint." Because NPS biologists have collected genetic samples from most mountain lions in the Santa Monica Mountains, geneticists in Robert Wayne's lab are able to try to match the DNA collected from the bite wounds or claws of the mountain lion that died to see if it matches another mountain lion that was previously sampled in the mountains. 

References

  •  CDFG. 2007. http://www.dfg.ca.gov/news/issues/lions/.pp.
  • Currier, M.J.P. 1983. Felis concolor.  Mammal. Species, 200: 1-7.
  • Guggisberg, C.A. 1975. Wild Cats of the World.  David and Charles Publishers.