On the night of June 11th, in 2011, a young cougar (Puma concolor) was struck and killed by an SUV on the Wilbur Cross Parkway near the coastal town of Milford, Connecticut (Kerwin, 2012).  At the time of death, the necropsy report indicated that this lean, two- to four-year old, sub-adult male had an empty stomach and porcupine quills embedded into his subcutaneous tissue.  Without any evidence of a captive lifestyle (not neutered or microchipped), genetic analysis confirmed that this cougar’s DNA matched that of the expanding wild cougar population in the Black Hills region of South Dakota.  Camera trap videos, paw print comparisons, and also a genetic trail of fur, scat, and leftover carcasses revealed that this cougar traveled throughout Minnesota, Wisconsin, Michigan, into Canada through southern Ontario, and then down into New York (approximately 30 miles from Manhattan) before his abrupt demise in southern Connecticut.  On the search for a mate and his own home territory, this big cat’s two-year journey covered a distance of nearly 2,000 miles. This more than doubled the previous, longest-known distance of 640 miles that was ever recorded by a dispersing cougar (Velsey, 2011). Male cougars disperse much further away from their natal ranges as compared to females but rarely do they ever travel more than a few hundred miles.

     This cougar’s incredible cross-country trek is also the longest known migration of any land mammal ever documented in the United States (Platt, 2011).  What made it even more remarkable was the fact that it was the first confirmed cougar sighting in the state of Connecticut in more than 100 years.  Cougars have historically occupied the entire expanse of the United States at a time when Native Americans both revered and peacefully coexisted with them (LaRue and Nielsen, 2011)(Fig.1).  However, that harmony shifted when early European immigrants began to perceive these big cats as major threats to human life and property (Glick, 2014).  By the turn of the twentieth century, these apex predators were ultimately hunted to extinction in virtually all areas east of the Rocky Mountains (Fig.2).  Records confirm that the last remaining eastern cougar was killed in 1938 near the Maine-Quebec border (Wright, 1961).  The only viable cougar population left in the eastern United States is now found in South Florida (Jacobs et al., 2015).  This small Floridian population was saved from the brink of extinction in 1995 through a highly controversial reintroduction of wild cougars from the state of Texas.  However, this population of only 80-100 breeding-aged adults continue to struggle and survive in less than 5% of their historic home range (Elbroch, 2018).

Insert Fig.1 map of “Historic home range of cougars (Pre-1900s)” 

Fig.2 map of “Cougar range post European settlement (Early 1900s)”.


     As cougars and other large carnivores help stabilize populations of potentially disruptive prey (Ripple et al., 2014), the 80-year cougar absence in the eastern United States has had an adverse rippling effect throughout the entire eastern area.  The East is now above the carrying capacity with the cougar’s preferred prey, the white-tailed deer (Odocoileus virginianus).  This unbalanced predator-prey relationship has brought about severe ecological disruptions and huge socioeconomic consequences to many parts of the East.


Ecological Disruption

     Deer have become the most prevalent and influential large herbivore in the eastern United States and are increasingly exceeding the environmental limits to many forested ecosystems (Cote et al., 2004).  The chronic browsing pressure by deer results in tremendous biodiversity loss and produces a negative cascading effect on the health and function of entire forests (Bressette et al., 2012). Overfeeding by excess deer prevents forests from naturally regenerating since individual plants, shrubs, and herbaceous layers are damaged and cannot recover.  Additionally, the openness to the forest floor alters the habitat composition of the forest and causes a shift in the colonization of non-native plant species (Horsley et al., 2003). These dramatic ecosystem changes interfere with normal food web interactions and greatly impact the livelihood and survival rates of many animal species found in the forest. The animals most affected are the ground-nesting bird species such as the wood thrush (Hylocichla mustelina), the Eastern towhee (Pipilo erythrophthalmus), and the hooded warbler (Wilsonia citrina) (McShea and Rappole, 2000).  Other affected animals include small mammals like the Allegheny woodrat (Neotoma magister) and the Tuckahoe masked shrew (Sorex cinereus nigriculus) (Van Clef, 2004).  Additionally, numerous reptiles, amphibians, and invertebrates are also greatly impacted.  Some examples include the bog turtle (Glyptemys muhlenbergii), the blue-spotted salamander (Ambystoma laterale), and the Appalachian tiger beetle (Cicindela ancocisconensis) (Heilferty, 2019).


Socioeconomic Costs

     Human health and safety are also greatly impacted by the overabundance of deer in the East.  Deer are statistically the most dangerous wild animal to people in the United States (Conover, 1997).  Deer serve as hosts to vectors to several zoonotic diseases such as Lyme disease and other tick-related illnesses (Levi et al., 2012).  If left untreated or undiagnosed, Lyme disease can have severe symptoms that include recurrent arthritis, memory loss, and neurological issues (O’Brien, 2015).  Documented occurrences of these tick-related diseases have reached an all-time high in every eastern state. Additionally, the number of deer-vehicle collisions have skyrocketed to an unprecedented rate of 1.2 million a year (Dickman et al., 2011).  These collisions in the East have resulted in more than 200 human fatalities, 29,000 injuries, and $2.3 billion dollars in damage costs. Lastly, deer cause the most damage to agricultural operations and private property residences than any other animal in the eastern United States (Maslo and Wehman, 2013).  Extensive crop damage results when deer feed, travel, or rest in agricultural fields. Crop damage costs eastern farmers a combined annual revenue loss of more than $3.5 billion dollars (Hewitt, 2011). The crops that experience the most damage are grains, soybeans, corn, lettuce, and tomatoes (Maslo and Wehman, 2013).


Cougar Range Expansion

     Despite the cougar’s intentional extermination in the midwestern and eastern regions of the United States, the cougar numbers in the western United States have rebounded as a result of hunting regulations imposed by most western states throughout the mid-1960’s (Sweanor et al., 2000).  However, cougars still only exist in a fraction of their historic home range as they are heavily impacted by human-caused activities such as habitat loss, habitat fragmentation, trophy hunting, poisoning, and predator control (Riley et al., 2014).  Current data indicate that some western cougars are now dispersing eastward as these anthropogenic stressors continue to increase throughout their western ranges (Thompson and Jenks, 2010). This movement is crucial for maintaining genetic diversity within populations and is essential for their long-term survival.  This long-distance natural dispersal has already facilitated new breeding populations in the Great Plain states of North Dakota, South Dakota, and Nebraska (LaRue and Nielsen, 2011)(Fig.3).

Insert Fig.3 map of “Current home range of cougars”



Coexistence Benefits

     Based on cougar predation rates from western source populations in the United States, the average cougar appears to kill between 30-40 deer a year (Laundre, 2013).  Based on this information, it was estimated that cougar restoration in the East would reduce the deer density by as much as 22% over a 30-year period. This could lead to 700,000 fewer deer-vehicle collisions and result in 155 fewer deaths, 21,400 fewer injuries, and a savings of more than $1.6 billion dollars (Gilbert et al., 2016).  Another study found that if the deer density were to stabilize in the eastern United States, the most damaged eastern forests could regenerate within two to three decades (Pendergast IV et al., 2016).  Just the predation threat alone affects herbivore behavior by reducing their overall feeding time, altering their forage movements, and limiting successful reproduction by increasing their stress hormone levels (Creel et al., 2009).  Cougars and other large carnivores also promote healthier herbivore herds by eliminating weak, disease-susceptible individuals. This ensures optimal genetic herd health by restoring the social order of dominance and allowing only the most fit males to breed (Van Clef, 2004).


High Risk Perception

     Although science has proven that living alongside cougars would actually save far more people from death and injury, cougars (and all large carnivores) are continuously stigmatized as “bloodthirsty” animals with malicious intentions.  A huge injustice occurs when these misunderstood animals, such as big cats, wolves, sharks, and others, are villainized in media outlets such as in Hollywood movies or in news reports. A substantial overestimation of risk is often associated with these animals and it causes most people to have an irrational fear of them.  Cougars, however, have much more to fear from us than we do from them because humans are by far the largest causes of cougar mortality (Guillain, 2014).

    Cougars have repeatedly proven that they are not a substantial public threat as there were only 29 human fatalities and 171 nonfatal attacks that occurred in the United States and Canada between 1890-2017 (Chester, 2017).  Although these incidents during the past 127 years are extremely serious, they come nowhere close to the 4.5 – 4.7 million Americans that are attacked by domestic dogs (Canis lupus familiaris) each year in the United States (United States Dog Bite Fatalities, 2017).  Statistics indicate that approximately 20-30 people die every year from domestic dog attacks, making people ten times more likely to be killed by a domestic dog than by a cougar.  

    Although the odds of encountering a cougar in the wild are very small and attacks are extremely rare, more cougar attacks have been reported in the western United States over the past 20 years than in the previous 100 (Guillain, 2014).  These attacks are directly related to the increasing human population and its encroachment into cougar habitat. There is, however, safety in numbers. Solitary hikers are three times more likely to be attacked by a cougar rather than people in a group.  Below is information on how to act when encountering a cougar (Anderson, 2006):


  • Make yourself look big.  Stay calm, face the cougar and raise your arms to look as large as possible.
  • Give it a chance to leave.  Most big cats try to avoid confrontation.  Back up slowly but do not take your eyes off the cougar.  Always leave the animal an escape route.
  • DO NOT RUN.  This may trigger an attack.  Scoop up young children so they don’t panic and run.
  • If approached, get aggressive.  DO NOT PLAY DEAD. Try to look threatening – wave your arms, yell, and be assertive.  Cougars can often be intimidated.
  • Throw rocks and sticks.  If bluster does not scare off the approaching cat, demonstrate that you are in charge.  The idea is to convince the cougar that you are not prey but a potential danger.
  • Fight back.  If the cougar attacks, fight back with anything you can get your hand on, such as rocks, sticks, shovels, even your bare hands.  Try to stay on your feet. If you are aggressive enough, a cougar will most likely flee realizing that it has made a mistake.
  • Report the attack.  Report the incident to local authorities immediately.


Coexistence Strategies

     Since 2005, there have been a total of 466 cougar confirmations in the midwestern United States and five confirmations in the Northeast (Cougar Network, 2019).  Most of these confirmations have gone unnoticed since cougars typically try to avoid contact with people. This was demonstrated by the Connecticut cougar who remained virtually unseen and undetected for two years until that fateful summer night.  However, as these big cats are steadily advancing past the Rocky Mountains, they are increasingly sharing more of the same space with humans in areas where they have long been absent. These dispersing cougars will need the full support and acceptance of the public if they are to have any chance of recolonization back into their former home territories (Davenport et al., 2010).

    The fear of human-cougar conflict plays a major role in anti-predator sentiments towards these large carnivores (Casey et al., 2005).  Overcoming the societal challenges and the “not in my backyard” mentality will ultimately determine if people have the ability and the desire to coexist with them.  Solutions to help foster positive public attitudes are essential, and significant investments into age-appropriate educational and public awareness programs should be a top priority.  Children should be a primary focus for the purpose of creating future generations of conservation-minded individuals.

    Knowledge of the cougar’s long-term valuable impact can also help diminish the negativity and fear that are associated with these apex predators (Prokop and Kubiatko, 2008).  Information about permanent human influences on the landscape, such as roads and urban developments, should be assessed to gain an understanding of how successful cougars are in avoiding these human disturbances.  Research into potential dispersal corridors should also be encouraged to help cougars safely facilitate their eastward expansion. Lastly, actions to reduce cougar encounters should be recommended by each eastern state’s wildlife agency with the interests of all stakeholders in mind (Table 1).  With more tolerance, insight, and some changes to our lifestyle, perhaps one day our long-lost eastern cougars will once again recover and unobtrusively roam the lands in which they formerly lived.


Table 1.

Actions to Reduce Cougar Encounters (Anderson, 2006):

  • Do not feed wildlife (deer, raccoons)
  • Remove plant, or protect gardens, that attract wildlife
  • Use garbage cans with tight-fitting lids to not attract wildlife
  • Bring pet food inside to not attract wildlife
  • Keep pets inside from dusk until dawn
  • Close off open spaces under structures (areas beneath porches and decks) that can provide shelter for wildlife
  • Keep outdoor areas well lit
  • Prune dense vegetation near your house
  • Provide sturdy and secure pens to protect livestock



    The cougar’s important predatory influences were not yet recognized when they were successfully eradicated from the eastern United States over a century ago.  Without any natural enemies, the ecological and socio-economic evidence is quite compelling that the deer population has become overabundant in the East. Methods such as sport and recreational deer hunting have not proven effective in the management of white-tailed deer and demonstrate that the cougar’s predation pressure in controlling such populations is unmatched (Williams et al., 2013).  Now that science has proven the value and worth of these big cats, the restoration of a natural predator-prey relationship in the East could be the much-needed solution for deer control. However, this will be for the public to decide. Whether or not cougars will be “allowed” back into the eastern United States, they are incredibly important animals that deserve protection. Not only for their valuable services to both the environment and to society, but also for the intrinsic value that they have in their own right.


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Jennifer Robertson works as a big cat keeper at the Philadelphia Zoo.  She completed this project as part of her graduate work with Project Dragonfly at Miami University in Oxford, Ohio.  (Contact info: rober162@miamioh.edu; Robertson.Jennifer@phillyzoo.org and 561-628-9683).

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