The mountain lion, Puma concolor, is a large, solitary predator known by many names, including cougar, puma, and panther. Historically, this species was the most widely distributed terrestrial mammal in the Western Hemisphere, ranging from the Yukon to the southern Andes. Today, its presence in the United States is concentrated in the West, a distribution shaped by ecological necessity and historical human interaction.
Current Geographic Range and Established Populations
Established, breeding populations of mountain lions are predominantly found in 14 to 16 Western states. These regions provide the expansive, rugged landscapes and abundant prey necessary to sustain stable populations. States with confirmed breeding populations include:
- California
- Colorado
- Utah
- Nevada
- Arizona
- New Mexico
- Texas
- Oregon
- Washington
- Idaho
- Montana
- Wyoming
- South Dakota
- North Dakota
The largest populations reside in states like California and Colorado, where thousands of individuals inhabit the mountainous terrain. The endangered Florida panther (Puma concolor coryi) is the only confirmed breeding population east of the Mississippi River. This small, genetically distinct subspecies is isolated in the pinelands and swamps of southern Florida.
Mountain lions sighted in Midwestern and Eastern states, such as Michigan or Connecticut, are typically transient individuals. These are usually young males dispersing from established Western populations to seek new territory. Since females rarely disperse as far as males, these sightings do not indicate a re-established breeding population.
Essential Habitat Requirements
The distribution of mountain lions is directly tied to specific ecological requirements. A primary necessity is a sufficient density of large ungulates, such as deer and elk, which constitute the majority of their diet. A single mountain lion typically requires enough prey to make a large kill approximately once per week.
The species is highly territorial and solitary, requiring vast areas to hunt and live without conflict. A male’s home range averages around 150 square miles, while a female’s territory is typically smaller, around 50 square miles. This need for extensive, low-density space limits the number of animals a region can support.
Mountain lions select for rugged, remote terrain that offers dense cover for stalking prey and establishing den sites for their young. They prefer areas characterized by steep, rocky canyons, forests, or scrublands. To maintain genetic diversity and prevent inbreeding, a population requires a contiguous habitat area of at least 10,000 square kilometers.
Historical Decline and Population Management
The disappearance of mountain lions from the eastern two-thirds of the United States resulted from human persecution beginning in the 17th century. Early European settlers viewed the animals as a threat to livestock and a competitor for game. This led to the widespread implementation of state-sponsored bounty systems, with states like Connecticut and Massachusetts offering rewards for cougar pelts as early as the late 1600s.
This systematic eradication effort, combined with habitat destruction and a decline in the white-tailed deer population, eliminated breeding mountain lion populations east of the Mississippi River by the early 1900s. When bounties were repealed in the West during the 1960s and 1970s, the cats were reclassified as game or trophy species, allowing populations to rebound.
Modern management in most Western states relies on regulated hunting, where state agencies use quota systems to control population numbers. These systems involve female harvest limits to protect the reproductive segment of the population and aim for sustainable harvest rates. This contrasts with California, which has classified the mountain lion as a “specially protected mammal” since 1990, banning sport hunting entirely.
One significant barrier to the natural re-establishment of the species in the East is human infrastructure. Large highways and urban sprawl prevent the movement of dispersing mountain lions, acting as physical and psychological barriers. This isolation fragments potential habitats and restricts gene flow between populations, preventing the formation of viable new breeding groups.