Residents of Los Angeles and Washington, D.C., could be forgiven for glancing over their shoulders when out for a stroll: Both cities have recently received reports of mountain lions living a whisker away from humans.

"It was really scary," Linda Miley told the Washington Post after seeing what she reported was a mountain lion in her backyard. "I got the shock of my life." Several other residents of Washington's southeastern area have also called 911 to report sightings of a mountain lion.

Though some officials remain skeptical of the Washington reports, there's no doubt that a fully grown mountain lion is now living in the hills and canyons of Griffith Park in the center of Los Angeles. Given the (rather ungainly) name P-22, the big cat was fitted with a GPS collar in 2012 and was tracked crossing two major freeways to get into the park, where deer, raccoons and other prey are plentiful. [Photos: Rare and Beautiful Amur Leopards]

"He has it quite easy for a young lion in Griffith Park," Jeff Sikich, a National Park Service biologist tracking P-22, told the Los Angeles Times. "There's no competition, and there seems to be plenty of prey for him."

The mountain lion (Puma concolor), also known as the cougar, puma or panther, was once common throughout North America, but was largely wiped out in the eastern United States by hunting and habitat loss — the U.S. Fish and Wildlife Service officially declared the eastern cougar extinct in 2011. A subspecies, the Florida panther, is listed as endangered.

But mountain lions appear to be staging a tentative comeback in some unlikely places: An adult male, believed to be from South Dakota's Black Hills, traveled east about 1,800 miles (2,900 kilometers), only to be struck and killed by a car on a Connecticut highway in June 2011.

"While the distance the Connecticut cougar traveled was rare, we found that cougars are roaming long distances and are moving back into portions of their historical range," Michelle LaRue, a University of Minnesota researcher, said in a 2012 statement.

In 2008, a mountain lion was shot and killed by police in the Roscoe Village neighborhood of Chicago, according to a report in National Geographic News.

Though mountain lion attacks on humans are rare, they are not unheard of (particularly in the western United States), and in most of the confirmed cases of cougar attacks, the victims are young children or solitary adults.

Police and other officials are continuing to respond to reports of the alleged Washington cougar, though some experts don't expect to find a cougar, and no tracks, droppings or other conclusive evidence have been discovered.

"I'm 99 percent sure it's not real," Ken Miller, co-founder of the nonprofit group Cougar Network, told the Post.

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