New Panthera Study Suggests Cougars Won't Recolonize Eastern U.S. By 2100...And Perhaps Not Ever

Media Contact: Susie Weller Sheppard, (347) 446-9904, sweller@panthera.org 

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Models estimate cougars will not relocate further east than central Minnesota or north of Orlando by end of the century – showing peak of natural cougar recolonization may have already passed

New York, NY – The return of cougars to their historic range in the eastern United States would have myriad positive implications for ecosystems and human health – but a study published today in Biological Conservation from Panthera, the global wild cat conservation organization, alongside the University of Montana, Washington Department of Fish and Wildlife and other contributors, suggests that in the absence of interventions from conservationists, cougars will not recolonize their historic range in the eastern U.S. by the year 2100, and perhaps not ever. 

The study found that cougars would reclaim just 2% of their unoccupied range by 2100, mostly in boreal Canada, with Manitoba being the only location that models indicate is certain to host a new breeding population. Oklahoma and Minnesota had just a 30% chance of one litter being born before 2100, and other states like Kansas (11%) and Iowa (2%) had even lower chances of seeing the establishment of new populations. No other unoccupied regions east of the Mississippi River were predicted to host breeding cougars by 2100.  

The findings were surprising: in spite of common cougar sightings in Ohio, Michigan, and other eastern states – including at least one as far east as Connecticut – and prior research positing that cougars would move into the Midwest within twenty years, the study illustrates the challenge of dispersal in landscapes rife with highways, people, and complex infrastructure. This research differentiates scattered dispersal of individual male cougars like the “Connecticut Cat” from recolonization by breeding males and females. 

Lead author Dr. Thomas Glass stated, “We know that cougars are showing up in the east, but most of them are dispersing males. We wanted to predict the likelihood of a male and female arriving in the same place at the same time, reproducing, and actually establishing a population. Our findings suggest the likelihood is pretty slim.”

Simulations found that eastward-moving females were primarily killed while crossing roads in the Midwest, or from hunting before leaving source populations. When the authors simulated nine road crossings and eliminated hunting in the Midwest, however, the model predicted little change in recolonization, due primarily to the considerable number of roads cougars must cross to reach breeding habitat.

The study utilized a computer model to predict the continent-scale future of cougars, specifically their movement in North America through the end of the century from strongholds in the west and Florida. The model simulated cougars dispersing from their current range, facing mortality risks, establishing territories, reproducing upon encountering a mate, and being born.

To capture the complexity of recolonization, the authors gathered extensive data from previous research, including cougar fecundity, survival, and cause specific mortality rates by region. Road mortality rates, for instance, were meticulously estimated by incorporating 42 cougar roadkill observations and nearly 1,600 successful road-crossings from GPS collar data to predict the likeliness of surviving road crossings of varying numbers of lanes and speed limits. To test the model’s performance, authors even “went back in time” to assess how well it predicted the timing and location of recolonization events that occurred between 1995 and 2023. 

Panthera Puma Program Director, Dr. Mark Elbroch, stated, “We set out to estimate the timing of natural recolonization, and surprisingly, our results suggest that we’re unlikely to see the species successfully recolonize the eastern seaboard by the end of the century. That means that if we want to see cougars in the East, we may have to reintroduce them.”

With State Wildlife Action Plans across the U.S. under revision, the findings are well-timed to provide northeast wildlife authorities with greater rationale to include cougars, which would support discussions about potential species restoration, as well as provide avenues for leveraging federal funds to do so. 

Covered in a New York Times opinion editorial, a 2023 Panthera study identified over a dozen landscapes bordering or just east of the Mississippi River that are large enough to support cougar populations, but they still need to get there. Cougars interact with nearly 500 species and their reintroduction could lead to healthier forests, less zoonotic disease and more benefits. Previous research showed cougar recolonization in the eastern U.S. could reduce deer-vehicle collisions by 22 percent over 30 years, averting 21,400 human injuries, 155 human fatalities and over $2 billion in costs. These findings are supported by the cougar’s return to South Dakota in the 1990s, which reduced deer-vehicle collision costs by an estimated $1.1 M annually.

Panthera’s Puma Program works on five priorities: 1) ensuring connected puma populations from Canada to southern Argentina, 2) facilitating peaceful coexistence between humans and pumas, 3) developing tools and future leaders to ensure long-term conservation impact, 4) changing and creating policies that increase conservation of pumas and their landscapes, and 5) facilitating puma range expansion into former range where they were extirpated..

Additional contributors include Audubon Canyon Ranch, USFWS, University of California and Victoria University of Wellington.