What is a mountain lion?
Mountain lions (Puma concolor) 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 its 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 do not imply increased danger in a given area. For safety tips, please visit the Mountain Lion Foundation website.
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 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 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 are 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).
Mountain lions are strict carnivores (i.e., they only eat animal prey) but they are flexible in their prey choices. However, mountain lions may have a strong preference for certain types of prey depending on where they live. For instance, in the Santa Monica Mountains, diet studies by the National Park Service have revealed that approximately 90% of investigated kill remains (see below) consist of mule deer (Odocoileus hemionus). Other common prey species are raccoons (Procyon lotor), badgers (Taxidea taxus), and coyotes (Canis latrans). These data were gathered by examining 390 kill sites in the Santa Monica Mountains made by 15 mountain lions.
To investigate mountain lion diet in the Los Angeles area, biologists rely on the radio-collar data gathered by GPS enabled mountain lion radio-collars that collect data (exact GPS locations) at prescheduled time points. 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 radio-collar, they will find clusters of data 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 prey remains. This often occurs weeks or months after the mountain 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 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 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 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, concealing the deer from scavengers. For several nights, the mountain lion will return to its kill to feed on it staying in the general region of the kill during the day to rest.
National Park Service biologists have never documented a mountain lion to kill domestic dogs or domestic cats in the study area though biologists frequently receive complaints that this occurs. 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. While it is not impossible that mountain lions will attack domestic animals, 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, and then re-caches the kill to save it for later. Watch this video to learn about Santa Monica Mountains mountain lion feeding behavior!
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.
For mountain lions studied by the National Park Service in the Santa Monica Mountains three primary sources of mortality include: 1) aggression between individuals– two animals may encounter each other in the mountain and then fight until one animal dies, 2) vehicle collisions, and 3) rodenticide (rat) 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 in the Santa Monica Mountains have died of other causes such as disease.
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. In order to collect these data, biologists first had to collect samples containing DNA from the mountain lions. These samples included blood and ear tissue collected during captures, tissue from road kill or mountain lions that were killed by State officials due to public safety concern, and hair and fecal material opportunistically found in the parks. Geneticists then extracted DNA from the tissue, hair, or fecal material. Next, the geneticists prepared a "cocktail" of ingredients that would enable the geneticists to identify specific characteristics of each genetic marker for each individual tested. The "cocktail" of ingredients includes water, enzymes, dye-labeled sequences of nucleotides ("primers") that bind with specific regions of DNA, and the extracted DNA from each individual. Once the cocktail is prepared, it is placed in a machine that can be programmed to have very exactly-timed heating and cooling cycles so that polymerase chain reactions (PCR) may occur. The goal of the PCR is to replicate specific regions (based on which primers are used) of the DNA to increase concentrations of DNA that are dye-labeled. Using PCR products, geneticists than use another machine to measure the size of each dye-labeled fragment that is replicated. In this way, we can gather information about the unique genetic information each individual possess.
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 connectivity between fragmented and scattered habitats 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 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 the use of foots snares, 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 ear tags, 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 road kills, 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.
- 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.