What's on P22's menu?

Have you ever wondered what P22, located in Griffith Park, is eating?  This is understandably a common question since he is a large carnivore living in a small park within the heart of urban Los Angeles.   In fact, he is more urban than any other mountain lion known to exist.  Local residents are only accustomed to sharing their backyards with smaller predators that don’t get any larger than coyotes.   However, mountain lions are relatively new members of the Griffith Park wildlife community and local residents and carnivore biologists are equally curious about what prey species he’s ambushing in Griffith Park.  I went on a gruesome scavenger hunt to figure out what he has been eating recently.  I am excited to now share a glimpse of what L.A.’s favorite mountain lion is dining on. 

A Little Background

Like all cats, mountain lions are strictly carnivorous (only eat meat), and locally, prefer deer to sustain their large bodies.  Their diet is one reason they are less adaptable to urbanization than a carnivore that is both smaller and omnivorous (eats plants and meat and so has more options in urban areas), like a raccoon.  Based on what we know from kill-site analyses conducted locally by the National Park Service (NPS) in the Santa Monica Mountains over the past decade, we know that local mountain lions are specializing on deer but do opportunistically pick off the occasional small prey item (e.g., coyote, raccoon).  To date, NPS has visited a few of P22’s kill-sites and have only found deer kills, which is a testament to the health of the Griffith Park deer population.

Mountain lions will cache large prey like deer, and often feed on it for several days.  They may drag it a few meters from the location of the kill and to cache it, cover it with dirt and leaf litter.  They will return to the site of a kill for multiple nights and repeatedly hide it until they finish feeding on the prey. During the day, they find a daytime resting location (day bed) not too far away from the kill site (generally at least several hundred meters away from the cache site).  If they kill a smaller prey species such as a rabbit or raccoon, they will usually consume all of it at once instead of caching the prey.  

Biologists use the GPS collar information to identify potential kill sites. Presently, biologists are able to access real-time GPS collar data through a website that remotely accesses collar data for each collared mountain lion.  The collars regularly send the data to the website via satellites or cell-phone tower transmission, like sending an email via a smartphone. 

Once biologists have the data, they look for GPS locations where the mountain lion has remained for multiple hours (more than 4) or returned on multiple consecutive nights.  However, even with pretty accurate GPS information it is not as simple to find these locations as it seems. The kills are never directly on human social trails. So, some obstacles that often make finding the kill difficult include poison oak, a pack of coyotes having the carcass away in multiple directions, thick vegetation, and especially difficult terrain.

Finding a Carcass in a Haystack

This past weekend, Laurel and I went out with a GPS and a few maps of potential kills made this past month.  We strategically parked in a location that was close to most of the kill sites.  We usually are able to hike to within 10 meters of the location, at which point we need to just walk around and not only look for bones or a buried carcass but also use our noses to narrow down the location.   Although, you never know exactly what the carcass is going to look like or exactly where it will be hidden, you can usually count on smelling the relatively fresh kills.  I definitely smelled all 4 of the kill-sites before we found them.  The carcasses were either found in deep ravines or on steep hillsides that required a great deal of bushwhacking mostly through poison oak.  

Wildlife CSI

Once we found the kill sites, we recorded data including the date we found the kill, the prey species, the exact kill location, sex of prey (when possible), and an age estimate of the prey if possible.  For deer, we had a guide to age deer by their teeth shape, definition, and degree of wear.  

Laurel recording data at the second kill site. 

We went to a total of 4 kills sites, which took us approximately 4 hours of hard work. We quickly found the first kill site, but only found the rumen (deer stomach).  We looked for the rest of the deer carcass for a while but coyotes must have dragged the body of the deer that was killed far away.  To be honest, I doubt we would have even found the rumen if it wasn’t so smelly because it was dried up and brown like the surrounding leaf litter. 

The second carcass was harder to find but Laurel finally found it deep at the bottom of a ravine.  Laurel shouted out to me with excitement!!!  “It’s a coyote!!”  I then told Laurel that it was the first documented P22 kill that wasn’t a deer, which added to the excitement.  However, this excitement was tempered by a little concern because mountain lions that consume urban coyotes are at risk of consuming a big dose of rat poison that has accumulated in the coyote over time (i.e., coyotes eat multiple rodents exposed to rat poison).  Nonetheless, I think it is amazing to imagine a large carnivore like P22 over-powering and even consuming another skilled predator.  I took a bunch of pictures of the remains that were barely identifiable without the semi-intact muzzle.  This was a pretty gruesome sight but surprisingly it wouldn’t be the messiest scene we’d encounter.

Next we visited another site nearby, which was a pretty classic scene.  Of course, we smelled it first and Laurel spotted the remains before I stumbled across them.  The rumen was again the first item to be discovered along with a couple bones before Laurel found the larger set of bones further away.  Again Laurel’s announcement was full of glee but she held in the details so I could totally take in the scene first-hand.  It was an overturned deer ribcage and skull with antlers attached.   It reminded me of a classic western movie scene at the point in the movie when death was looming.  It would’ve been awesome to see P22 take down such a large mammal!!

The fourth and final carcass of the morning was supposed to be the easiest to find but turned out to be the toughest due to tricky terrain, dense vegetation, and unavoidable poison oak.   Laurel again was first to spot the carnage at the bottom of the poison oak infested ravine.   I have seen plenty of raccoon road kill scenes but this scene seemed more intense.   It was a big raccoon with bloody limbs spread all over the place.  It seemed as if P22 and maybe later some coyotes attempted to consume almost every morsel of available meat to the point where it seemed like the carcass was turned inside out.  The very distinct raccoon hand-like paws were left intact, which made the scene pretty memorable.  Although it wasn’t a deer, it was equally interesting because it was an uncommon mountain lion kill to walk in on.  It is a rare opportunity to walk in on small prey because the mountain lion doesn’t stay very long or leave many remains which makes it hard to notice.

Why bushwhack through thick vegetation and poison oak to find smelly P22 left overs?  No, not because Halloween is a month away but because as the most urban mountain lion known to exist, P22 is providing invaluable insight into mountain lion ecology.   This scientific information can be used to help educate wildlife managers and biologists about mountain lion feeding ecology, prey-preferences in smaller urban parks, adaptations to urbanization, and conservation concerns (e.g., exposure to rat poison via ingesting contaminated urban coyotes).  Equally important is that this scientific information translates into educational information that dispels myths about urban mountain lions such as seeking out pets or becoming dangerously habituated to human subsidized food resources.  P22 is telling us that he is retaining the same natural behavior of his more rural counterparts and going after deer and other natural prey in the wildest patches of the park.  These grizzly (awesome) scenes also may provide a sign of hope for Griffith Park remaining a functional urban oasis.  However, the park may not remain sustainable without promoting human-wildlife coexistence and using proactive management to keep key areas wild.