Dan Stahler finishes the field examination of the newly GPS-collared adult male M198 before reversing the immobilization drug, after which the cat got up and walked away. (Photo by W. Binder)

They lurk in the mountains, leading solitary, nearly unnoticed lives. But while grizzly bears and wolves hold Yellowstone National Park’s large carnivore spotlight, mountain lions quietly thrive as one of the ecosystem’s major predators.

Largely forgotten by the park-going public, cougars get plenty of attention from park wildlife biologist Daniel Stahler. Stahler just completed the fourth winter of a five-year study to better understand how the cougar population is responding to landscape and prey competition from growing grizzly bear and grey wolf populations.

“We’re viewing this as a multi-carnivore system, which makes Yellowstone unique and special,” Stahler said. “Yellowstone today is as carnivore rich as it has been in over 150 years. In terms of ecosystem restoration, it’s a wonderful success story.”

And while the study isn’t yet done, data shows the cougar population in the park is adaptable and thriving.

Mountain lions in the Rocky Mountain West shared a fate with other feared predators of the region. By the 1920s the last cougars in Yellowstone ecosystem were gone. Like wolves they had been poisoned, trapped and shot until extirpated, Stahler said. But while wolves required human help to return to the park, cougars crept back on their own, re-establishing a small but robust population of about 15 to 22 animals in the late 1970s and early 1980s.

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Remains of a killed porcupine were found by tracking an adult male cougar near Pebble Creek. Cougars are one of the few predators adept at killing and consuming this formidable prey. (Photo by Daniel Stahler/NPS)
Remains of a killed porcupine were found by tracking an adult male cougar near Pebble Creek. Cougars are one of the few predators adept at killing and consuming this formidable prey. (Photo by Daniel Stahler/NPS)

Wildlife management helped the species rebound. Regulations treated mountain lions as trophy animals with hunting quotas and restrictions instead of as predators which could be indiscriminately killed on sight.

Park biologists launched the first of three major cougar research initiatives in the 1980s with the goal of establishing a baseline population estimate. Scientists again studied the animals from 1998 to 2006, this time looking at how wolf reintroduction and a growing grizzly bear population impacted the lions of the park.

“It was an era of carnivore restoration,” Stahler said. “Everything was coming back, but it meant they all had to share the landscape.”

Despite competition with the other carnivores, the estimated cougar population rose to more than 40 animals, Stahler said.

“It’s a wild place, there’s a lot of food and habitat and these carnivores could sort themselves out,” he said.

That second research project also explored new, non-invasive ways of studying the animals such as tracking them with DNA from hair left on rocks, branches and even in tracks, said Michael Sawaya, a wildlife ecologist who worked on the study. Researchers were able to learn about the population without actually handling and collaring animals.

In 2014, Stahler and other biologists wanted to again check on the cougar population and started the current five-year study to see how declining elk populations and increasing competing predator populations were impacting the mountain lions.

The new research gives a complete picture of how many predators are on the landscape and what that means for elk populations, Sawaya said. Yellowstone offers a unique place to study because the population is un-hunted and in a protected area. The data shows how the animals survive in a protected system, he said.

Stahler is focusing on cougars in the northern part of Yellowstone where the animals live year-round. He tracks the animals to bed sites where he collects hair samples they’ve left behind.

Yellowstone Cougar Project field technicians Aaron Morris (left) and Marcus Bianco (right) record data using a GPS unit and iPad data logger before collecting a portion of cougar scat for DNA analyses. (Photo by Daniel Stahler/NPS)
Yellowstone Cougar Project field technicians Aaron Morris (left) and Marcus Bianco (right) record data using a GPS unit and iPad data logger before collecting a portion of cougar scat for DNA analyses. (Photo by Daniel Stahler/NPS)

Stahler recently wrapped up field work and hasn’t analyzed this winter’s data, but based on findings from the previous two years, he believes there are 22 unique animals in the park.

“That’s a pretty healthy population,” he said.

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Field technicians Wes Binder and Kira Powell record data at an adult male cougar’s fresh scrape in the snow. Cougars, especially males, make these shallow depressions with their hind feet and deposit urine and/or scat, creating a visual and olfactory communication station. (Photo by Daniel Stahler/NPS)
Field technicians Wes Binder and Kira Powell record data at an adult male cougar’s fresh scrape in the snow. Cougars, especially males, make these shallow depressions with their hind feet and deposit urine and/or scat, creating a visual and olfactory communication station. (Photo by Daniel Stahler/NPS)

The stable numbers show that even as elk decline, mountain lions can find other food and thrive despite sharing the landscape with more carnivores.

“Wolves have had a significant force on the landscape, but cougars have adjusted,” he said.

Stahler also collared three mountain lions to track their predation habits. The study gives a sense of how cougars use the landscape. The findings can be applied to other areas where humans are encroaching on mountain lion habitat.

“This is valuable data in looking at conservation of these carnivores,” he said.

The research project will continue for one more winter. Once complete, researchers plan to compare the fresh data with those of previous studies, including one set dating from the 1980s. Population monitoring is the primary aim, but scientists hope also to gain a better understanding of genetic diversity within the cougar population in the protected system.

Sawaya and his colleagues would then like to see an expanded version of the study done ecosystem wide across state and federal jurisdiction to give a bigger picture of how these types of carnivore populations, which need large swaths of land, survive.

An adult cougar moves across the landscape. (Photo courtesy Daniel Stahler/NPS)
An adult cougar moves across the landscape. (Photo courtesy Daniel Stahler/NPS)

Kelsey Dayton is a freelancer and the editor of Outdoors Unlimited, the magazine of the Outdoor Writers Association of America. She has worked as a reporter for the Gillette News-Record, Jackson Hole News&Guide...

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  1. Wyoming (more than most states) appears to be maintaining a park for predators. The count of predators is most important for the safety of visitors and other animal populations that cannot defend themselves. As it is now, people can not safely hike or camp without extreme caution and diligence. Even then, some lose limbs or lives. [Some will not allow camping in tents now as it is not safe enough.] Parks were not established just for the animals, and most definitely not for the predators. Though ‘we the people’ pay for for the parks with our taxes and entrance fees, we cannot enjoy the sanctuary it was intended to be for us, as well as for the animals.

    Control of populations is an important factor. In Alabama, they have some of the healthiest population of deer. They also have the most lenient hunting laws. Why is there no problem? Because studies, and counts are done annually. Then hunting limits are established and enforced. I am sure it is the same for other species. The count is necessary, just as hunting is necessary for all to stay healthy. One cannot keep protecting predators (failing to count) or one has become irresponsible in wildlife preservation; and become responsible for lack of safety.

    This past year, In northwest Florida, a local paper blamed a dog (on owner’s leash)
    for a bear attack at night (!) The dog started barking and was killed by the bear. The owner was hurt trying to save the dog. Overpopulation of bears in that area was the cause and many hungry bears are out searching neighborhoods for food. Of course, no responsibility was taken for the overpopulation. Why? because they will not confess to overprotection – FAILING TO TAKE INTO ACCOUNT THE NEED FOR A ‘COUNT’. Consequently, cities have become a park for predators and the predators aren’t healthy either.

    In India, children have become the desired meal of the tiger and the tiger ventures out of the reserves to obtain them. Why? because there are too many and they are hungry. Maybe those in authority do not care if people are attacked or lose children ? They can continue to miscount or hide the numbers protecting the predators. But if they do, they are directly responsible for the death of innocent children and pets, unaware adults, and animal populations unable to defend themselves. In the US, the park officers are also responsible to the public (citizens) who pay their salaries. Legislative action to hold these accountable for the COUNT in the future is necessary ….and lawsuits will follow by those that have been harmed and incurred great loss.

    1. I’m sorry but that is ridiculous. There have been far less people killed by bears in Yellowstone that by the Thermal features (geysers, hot springs, fumes, etc), as well as by Bison and Elk.only about 2 people a year die in the US from Grizzlies (Brown Bear) and about 1 per year from Black Bears in the US… And they live in about 40 states. There’s only been 2 fatalities EVER recorded from Wolves in the US, your in far more in danger from lighting in Yellowstone than that and same with driving thru the park.

  2. North Stonington, CT, is flush with cougars/pumas/catemounts/mountain lions. The population is growing in central, south central and eastern parts of the state. They’re spotted all the time~~~I came across one myself some years ago~~~but the state’s official stance is that mountain lions are “extinct” in CT. As if these cats recognized state lines and turned back!

  3. I have heard anecdotally that the two places in North America with the highest density of population of Cougars are the state of Wyoming, and Vancouver Island. The state wildlife agencies in California say as many as 5,000 may exist in their state, and Oregon says 3,000 there.

    How many in Wyoming ? That number is not made public. Wyoming Game and Fish refuses for whatever reason to publish an official estimate of the state’s Cougar population. Which to my mind is disturbing, but well within the boundary of biases my state has towards any large predator in skewing or hiding carnivore numbers. It’s helpful when it comes to hiding their ” management “.

    Using habitat data from elsewhere in the West , it is possible to extrapolate a base population for Cougars within Wyoming . The models work out to about 1.7 to 2.4 animals per 100 square kilometers, yielding a population of a minimum of 1800 to 2400 of the big cats. The actual population is higher, but unknowable by the general public. Unless and until Wyoming Game and Fish releases data, and that data is peer reviewed and added to the knowledge base of Cougars, we have no way of knowing the gross population.

    But we do have a grasp of the human caused mortality of Cougars statewide, and it’s alarming. Hunters are taking nearly 300 Cougars per year now in legal limited quota hunts, and those are actual Wyo G&F hunter harvest numbers. Some researchers estimate the total human caused mortality of Cougars including all causes of deaths plus a ballpark estimate of orphaned cubs not surviving their mother’s loss, the number remove each year could be well above 1,000 Cougars. Researchers believe Wyoming’s man-caused mortality of Cougars is almost an order of magnitude higher than any other Western State. That’s the alarming part I referred to.

    Again, Wyoming does not make public any estimates of Cougar numbers, and that sequestered data is thus not peer reviewed. That needs to change. There is no justifiable reason to keep Cougar data from the public. It is slowly dawning on people that large carnivores are essential to landscape scale ecology , but large carnivores have been wrongfully killed for the past century for the wrong reasons to appease the wrong special interest groups. The Moo and Bleat brigades. Wyoming’s predator policies remain firmly rooted in the Dark Ages by fiat from the Stockgrowers.

    One final note. Cougars are not Lions, and should not be called Mountain Lions. That is folk ignorance. Just because it is the widespread colloquial name used to identify Cougars , calling them Mountain Lions is a misnomer. Even the professional wildlife biologists are guilty of it. There are no Lions in the New World. Cougars are the largest member of the cat family — Panthers —- and there are six subspecies of them in the Western Hemisphere. But only one subspecie north of the Rio Grande. Call them Cougars, Pumas, or Catemounts. But they aren’t Lions. They do not roar.

    1. P.S. – I ,too, have a hard time believing that only 40 Cougars call Yellowstone home. While it’s true that Cougars prefer deer as their main meal staple and Yellowstone is not exactly bulging with deer herds, 40 Cougars seems low by an order of magnitude. But like the author points out, the big cats are stealthy and stay hidden. I’ve only seen two live Cougars in my life, and one was a starving cub eating from a bowl of canned dog food.

      Three years ago my City Councilman had a Cougar in his back yard . He lives in the middle of town on the rim of the river terrace , with the LDS church as his immediate neighbor , a block from the Post Office across the street from the Rec Center. He goes out to mow his lawn with a riding tractor and woke up a darn big cat with a 3-foot tail dragging. It vanished into thin air . At 11 AM on a Tuesday. Cody has about 300 Mule Deer living inside the city limits on any given day , and the Cougars take advantage of it. There have been a few incidents and sightings over the years. But for every Cougar you see, there are X-number you never see.

      A friend of mine in Boulder CO told me a story that the city of Fort Collins attempted to do a census a few years ago of Cougars frequenting their city, after some well publicized encounters between Cougars and joggers/ dog walkers. What they found was evidence of so many COugars traipsing thru town at night that they dare not release the results for fear of scaring the public. Urban legend ? Maybe. But Fort Collins and the Colorado Front foothills are not short of big cats… just try to find one, though. Anywhere. ( Hint: use a hound)

  4. I doubt only 40 cougars are present in the 2+ million acres. Cougars seem common in the Salt River/Wyoming range (south of Yellowstone.) Add mountain lions as another example of how the Wyoming Game and Fish does a great job protecting Wyoming’s wildlife.

  5. Just 40 cougars on 2+ million acres is an indication that trophy & sport killing is not scientifically justified. “Sport & “trophy” hunting should be banned within all our national parks. Predators such as these will control their own numbers without the need to “control” these big cats.

    1. If this population estimate for the pumas is correct, it tells me that the Wolves are having a big impact on the pumas.Wolf Pacts are rather large in the Yellowstone, and the big cats would not do well against a big Pact. One on One Puma’s would do very well against the wolves, but that is not the way the wolves would fight. It would be One puma against a dozen or more wolves.

  6. As the rise in vistors increase each year at YNP,how do you think this will influence the cougar population in the park ? Thanks.