Science Friday - Should we bring mountain lions back to the Northeast?

Episode Date: June 15, 2026

Big cats used to roam the entire United States. You might know them as mountain lions, pumas, cougars, or catamounts. Though they go by many names, they're actually all the same species.  Their current population is mostly confined to the West, and part of Florida, though in recent years they’ve been spotted in other areas east of the Mississippi River. Most cougars were gone from the Northeast by the 1800s, with the last verified accounts in the 1930s.  Mountain lion ecologist Mark Elbroch hopes to reintroduce these big cats back into their previous habitats in New England. But, should we? What are the benefits and drawbacks of reintroducing the apex predator into an ecosystem it's been away from for so long?  Guest: Dr. Mark Elbroch is the director of the puma program at Panthera, a big cat conservation organization.  Other episodes you may enjoy: Surveying wildlife along Lewis and Clark’s route, 220 years later Are Raccoons On The Road To Domestication? Transcripts for each episode are available within 1-3 days at sciencefriday.com. Subscribe to this podcast. Follow our show on Instagram, TikTok, Facebook, and Bluesky @scifri and sign up for our newsletters. Got a science question that’s keeping you up at night? Call us: 877-472-4374 Hosted by Simplecast, an AdsWizz company. See pcm.adswizz.com for information about our collection and use of personal data for advertising.

Hi, I'm Jane Lindholm, and you're listening to Science Friday. I'm filling in today for Flora and Ira. Big cats used to roam across the entire United States. You might know them as mountain lions, pumas, cougars, or catamouts. They have many different names, but they're actually all the same species. Their current U.S. population is mostly confined to western states and a small population in Florida, though in recent years they've been spotted east of the Mississippi River. Most mountain lions were gone from the northeast by the 1800s, with the last verified accounts in the 1930s. My next guest is a mountain lion conservationist hoping to reintroduce these wildcats back to their previous habitats in New England. But should we? Dr. Mark Elbrock is the director of the Puma program at Panthera, a big cat conservation and advocacy organization.

Mark, thank you so much for joining me. Yeah, my pleasure. Thanks for having me on the show. Let's just jump right in. Why would people want to bring mountain lions back to the northeast? Ooh, that's a great question. I think one is that sort of reintroducing species that were previously part of ecosystems in the east is, quite honestly, a core American value. You know, it's been part of American culture, at least our conservation culture, for more than 100 years. We have reintroduced hundreds of species. People don't even realize it.

Like that black bears, white-tailed deer, river otters, beavers, all of these things were rare at one point in New England or absent in parts of New England and were successfully brought back through reintroduction efforts and protections. And so I think it's fair to say that, you know, it is a core value of American people to say, we did something wrong,

and we want to write that wrong and bring back and rebuild the ecosystems which we changed. Beyond wanting to maybe repair something that humans could say we were the ones who damaged, is our ecosystem missing anything without mountain lions? Yeah. So, I mean, large carnivores contribute all sorts of things to ecosystems. And one is that they bolster the ecological health and resilience of an ecosystem,

meaning that they are better armed with the sort of internal mechanisms needed to protect themselves after a fire, a wildlife disease outbreak, a timber harvest. And the ecosystems can recover from those events more quickly when they have systems that are more complex. And large carnivores add to that complexity. And then the other is that they make animals afraid. And as strange as that sounds, it's a really important thing. And so, for instance, their primary prey, which in New England would be deer, would be pooping in different places, they'd be hiding in different places. And it really spreads nutrients across the landscape in different ways than in their absence.

And those fear effects are, you know, really important for us as well. You know, we just did a really cool study out where I live in Washington State, very much like New England, in Western Washington, least in terms of a rural landscape. But we looked at the impact that the local mountain lines were having on deer collisions with people and their cars. And we found that the areas where the mountain lines were close to the highways and they were scaring deer away from them, they were reducing local deer collisions with cars by 76%.

I mean, that's a huge number. And it translates into millions of dollars of savings for local communities. And that's the kind of thing that that fear, you know, can create on the landscape. I live in Vermont, and there are many Vermonters who say Mountain lions, or as we call them, catamounts, never actually left. And people have been spotting them for the last 150 years. Not possible? I wish it were true. You know, I lived in New England much of my life as well.

And in fact, while I was in New England, I think I investigated. 53 sightings, you know, going around and to verify whether these were truly mountain lions or not. And one of them ended up being a mountain line. But, you know, even when they have been verified as mountain lion, those that have predominantly been documented have been from other places. We expect that they were, you know, exotic pets that were released into the wild. Now, all that said, occasionally a wild mountain lion does make it to New England. And I think, you know, the most exciting example of that was in 2011 when a mountain line, you know, that we know originated from the Black Hills of South Dakota, made it all the way to the East Coast. I mean, in a remarkable journey that was documented with not just photographic evidence of, you know, people who had cameras in their backyards, but also genetic evidence that was gathered by different state wildlife agencies and then later compared with each other and goes, oh, my goodness, it's the same one that diet.

in Connecticut in 2011. So it was an amazing story, and it just shows that it is possible. So I like to say that to folks that it is possible that they really did see a mountain line in Vermont. It's just highly unlikely. Yes. And no established breeding populations. There are no established breeding populations in New England, no. I wish that were true, too. Well, let's talk about what it would take to bring back breeding populations in New England. Do we have the right ecosystem now, or are there further steps that would need to be taken before mountain lions could successfully survive here? Great question. And an easy answer. So I'll just start by saying the mountain lions are generalists, meaning that they inhabit every kind of forest and almost every kind of habitat available in North America. And so is there habitat in New England? Absolutely. And is there food for Mountain Lions in New England? Well,

their most common prey in the West are deer, elk, beavers, porcupines, and raccoons. Other than elk, we have all of those things in New England. What about forest fragmentation? Not a huge deal in Vermont, but in some of the New England and northeastern states, a lot more highways that could cause problems for moving mountain lions. Yeah, so highways are a big issue for mountain lions in the same. sense that generally mountain lines don't make home ranges that overlap a highway. So they don't split one side, you know, spend half their time in one side, half their time and the other.

And so we generally see large highways that have heavy traffic loads. They're not always a barrier to movement because young mountain lines, which we call dispersers or transients, the ones that are looking for a territory, they will cross these highways, even with heavy traffic loads. And that's what ensures the genetic health of all mountain lines scattered across an area with highways in it, because they'll go across the highway and carry with them genetic material into those mountain lines that live on the other side. And so a landscape like New England, no problem at all. And you need very few crossings to really maintain genetic health. I mean, that's one of the revelations in the last 10 years in terms of mountain lions is that a single animal that crosses a highway,

into a new population is enough to really bolster the genetic health of that population. You know, Mark, perhaps an even bigger stumbling block is making sure that you have both political and public buy-in for a project like this, especially when we're talking about an apex predator or an animal where there is some cultural fear around. In this case, Vermont has started to become sort of the epicenter of this reintroduction idea so far. It was the first state to introduce a bill that would study the reintegration of Mountain Lions. That bill didn't move forward, but it did come up in the legislature. There's an environmental advocacy group called Mighty Earth that has started pushing this project.

I see some of their road signs out in my neighborhoods. And they've even said that they'd like to have paws on the ground in four years. But there is pushback already to the plan too. Vermont Fish and Wildlife has said it's too soon to be considering reintroduction. There's still a lot more research that needs to be done, they say. So how much of a reintroduction plan is actually about political and community education? Well, for this species, it's all about public outreach, education, and political will. And the team that I work with, which we loosely call ourselves the Cougar Research Collaborative, has already done public surveys at the

state level. What's been very clear is that across the east that we've sampled, people are supportive of the reintroduction of mountain lines. People are supportive regardless of their political affiliation or how they identify as a hunter or whether they call themselves a conservative. I mean, all of these things, even across age groups. So we feel like that part has been quite well addressed. Now, could we broaden the net? Could we reach out to every different group of, you know, that might be called a special interest group, to check in with them if they would support such an initiative? Yes. And that actually is generally what happens during a feasibility assessment.

And that's what Vermont proposed to do. So that's one part. Political will is the other thing you brought up. And in fact, that's probably, you know, in terms of a reintroduction of this species, the bigger issue. And I think it's fair to say that at this point, we have yet to identify a champion. And by that I mean a person or a state or a group of individuals that are either legislators, governors, leadership in a state wildlife agency that are genuinely enthused about this idea and are ready to kind of carry it through the inevitable pushbacks that will come up.

And I say inevitable not because there isn't public support, but because state wildlife agencies have so much old inertia because they are still running themselves as they were designed to do over 100 years ago, and it's just not conducive to embracing and reintroducing large carnivores. But I do think it's important to emphasize that all of these state agencies are strapped for cash. They all have the list of things they'd like to do, and they all have a budget that doesn't meet those desires. And so when an outside group comes in and says, hey, we'd love you to do reintroduction of Mountie,

Mountain Lions isn't even on their radar. Of course, the response is like, my goodness, we can't even keep up with our current priorities. And if we were given money, would this be one of our top priorities? Do you think it's actually going to happen? Are we going to see wild mountain lions in the Northeast in your lifetime? I believe it's possible. That's not very affirmative. I'm not the decision maker. Yeah. You know, if it were up to me, I'd say absolutely. All we need is that political champion who says, let's do this. I want part of my legacy to be rebuilding the health of these local ecosystems

that we can, as a community of people, embrace that reintroduction as well and be proud of it. Well, Mark, thank you very much for sharing your enthusiasm for these Wildcats with us and your expertise. I appreciate it. Sure. My pleasure. Dr. Mark L. Brock is the director of the Puma program at Panthera, a big cat conservation organization. This episode was produced by Shoshana Bucksbaum. If you enjoyed this conversation or have ideas of what else we should cover on the show,

leave us a voicemail at 8774-Sye Fry. 877, the number four, sigh-fri. Our listener line is always open. I'm Jane Lindholm. Thanks for listening.