The findings, detailed in The Journal of Wildlife Management, showed 178 cougar confirmations in the Midwest and as far south of Texas between 1990 and 2008. While confirmed sightings of Midwest cougars were sporadic before 1990, when there were only a couple, that number spiked to more than 30 by 2008, the study shows.
Researchers said the study poses fresh questions about how humans and livestock can co-exist with the re-emerging predators, whose movements appear to be following natural dispersal instincts.
The study sorts through various reported sightings and affixes a number to those it could confirm, which is significant because no government agency tracks the number of large cats across the country. And wildlife officials for years have said it's unclear how many of the animals may be in the Midwest, where they are not federally protected and, in some states, are subject to being hunted.
"We (now) know there are a heck of a lot more cougars running around the Midwest than in 1990," said Clay Nielsen, a Southern Illinois University wildlife ecologist who co-authored the report while heading the nonprofit Cougar Network's scientific research. "We've got an interesting and compelling picture to talk about now.
"For those who are excited about the notion of living with large carnivores, this is great," Nielsen added. "For those worried about livestock degradations, there's going to be division in the ranks in the Midwest. It's going to be interesting to see how the public responds if this colonizing continues."
In the study, researchers relied on carcasses, cougar DNA from scat and hair samples, animal tracks, photos, video and instances of attacks on livestock across 14 states and Canadian provinces to measure the number of cougars east of the Rocky Mountains.
Scientists long had suspected that cougars were migrating from the West or South Dakota's Black Hills mountain range, where populations of the big, long-tailed cats have been so abundant that the state has staged a yearly hunting season targeting mountain lions since 2005. The study excluded confirmations from the Black Hills, given that state's bounty of puma-breeding populations.
Of the cougar confirmations by researchers, roughly 62 percent took place within some 12 miles of habitat considered suitable for the animals' populations. Sixty-seven of the confirmations were in Nebraska, 31 in North Dakota, 12 each in Oklahoma and Texas, 11 in South Dakota and 10 in Missouri. Single-digit tallies were in Arkansas, Louisiana, Minnesota, Iowa, Illinois, Wisconsin, Kansas and Michigan.
Researchers theorize cougars are inhabiting the Midwest again following a "stepping stone" dispersal pattern -- moving out of a dense population, stopping at the closest patch of available habitat and examining it for mates and prey before moving on. One male cougar made its way as far as Connecticut, where it was hit and killed by a vehicle.
Such cougar dispersal "is what they're programmed to do. Young mammals, even young humans, tend to move away from home," said Paul Beier, a Northern Arizona University conservation biology professor who studies cougars. "They once occupied the mid-western U.S. There's still some appropriate habitat, and this is how they'll find it."
Cougars are known to be largely secretive and mostly keep to riverbanks and wooded areas, usually avoiding humans while feeding on deer, turkeys and raccoons.
But at times, the predators have drifted into populated areas. Police in Santa Monica, Calif., last month killed a 95-pound mountain lion that roamed into a downtown area -- the first such sighting in that city in more than three decades -- and Chicago police in 2008 shot and killed a 150-pound cougar in an alley on the city's North Side.
The study's findings come as little surprise to Bill Jorgenson, a North Dakotan who came face to face in January of last year with a 130-pound female cougar and her three cubs in a storage barn on property where he has 20 horses and some 1,000 head of cattle.
Jorgenson, fearing for his safety, shot and killed the animals.
"They're so thick out here, it's unbelievable," Jorgenson, 58, said of the mountain lions he blames for "wiping out" the deer population around his home near the 1,700-resident town of Watford City. "Two years ago, it'd be nothing to see 200 to 300 mule deer out there; this past winter, we never saw more than 20. We have carcasses all over where they've been killed."
Missouri's Department of Conservation said recently the 14 confirmed cougar sightings in that state this year compares to a dozen cougars confirmed there over the previous 16 years.
Since 1996, Missouri has deployed a specially trained, evidence-collecting "Mountain Lion Response Team" of wildlife experts, law enforcers and biologists whenever there's a credible sighting of cougars.
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