Don't let the cat out. The wily coyote is making himself at home inside the Beltway.

Once a marquee image of the American Southwest, coyotes are no longer strangers to these urban parts. Their numbers are on the rise in every jurisdiction of Virginia and Maryland, and they have most recently been spotted in Falls Church, state and local wildlife biologists say.

While they have yet to move into the District, the long-snouted, furry-tailed creatures have been sighted as close as Arlington County and Silver Spring. Laura Illige, chief ranger of Rock Creek Park, said that "it's only a matter of time" before coyotes will be seen howling with Washington's famed monuments as a backdrop.

In Falls Church, where several pets have been attacked, city animal control officer Rebecca Keenan is advising residents not to allow cats or small dogs to roam, especially at night.

At the West Falls Church Metro station, a Lhasa apso was set upon by a coyote as the dog was being walked by its owner Monday night. The man was able to protect the dog by throwing rocks at the coyote to scare it off, Keenan said.

Nearby, a cat was killed in front of its owner in late May by a pair of coyotes. The woman screamed and thought she had scared them off, but they circled around the house and went after her other two cats in the back yard. She was able to get those pets inside.

Since then, the city's animal control office has received reports of coyote sightings almost every day, Keenan said.

The population growth of the coyote, an animal Native Americans call the Trickster, will likely force humans to adapt to the presence of the animals rather than the other way around, local and state officials say.

"We feel like citizens should be aware that they are here to stay," Keenan said. "We have extraordinarily diverse wildlife in this area. You'd be surprised at what's running around."

Bill Brew, who lives on the border of Falls Church and Arlington, said he was brushing his teeth in his downstairs bathroom one morning last week when he saw a pair trot right up to the window.

"One was 10 feet away looking in the window right at me, and I was thinking, 'Hello,' " he said. "They looked like a couple of scrawny dogs."

People are rarely the targets of coyotes, although rabid coyotes will attack. They usually contract rabies from hunting infected raccoons and bats. The only known human assault in Virginia in the past five years was in New Kent County in January 2003. In that case, a man riding a lawn mower was attacked by a rabid coyote weighing about 50 pounds, large for a coyote. After kicking it away several times, the man was able to get his shotgun and shoot the animal as it chased him to his front porch, state records say.

State wildlife biologists say the coyotes in the Washington region are nearly twice the size of their cousins in the Southwest and can run up to 35 mph. Virtually nonexistent in this area 20 years ago, they already seem to be losing their fear of humans.

"It does appear they have adapted to urban environments," said Dan Lovelace, a Virginia wildlife biologist. He added that residents should be careful not to leave pet food outside and should be sure to secure garbage can lids "to prevent that acclimation to humans."

Coyotes possess a wealth of hunting skills. They look like wolves, are much stronger than foxes and can silently sneak up on their prey and then pounce, like a cat. Wildlife biologists say they are highly adaptable and can eat up to 100 kinds of food, including insects, pets, grass, fruits and even shoe leather.

Some local residents view them as vermin and are calling for their eradication. That, though, might be impossible, Keenan said. Coyotes are too smart for leg traps, and it would hardly be safe to allow hunters to shoot them in city streets, she said.

"It would be like saying you need to get rid of all the raccoons in the area," she said. "I mean, how do you do that? It's hard."

Coyotes, which are active at night, are encroaching on residential areas at an increasing rate. They pose a threat to pets but rarely attack people.