A black bear has been bounding through back yards in Germantown for the last two days, bringing suburban life to a halt wherever it has turned up--even at the local swim club.

Lauren Erb, coach of the swim team at the Water's Landing pool B, said she first encountered the rare visitor on Thursday.

"We started getting these calls from parents in the neighborhood saying, 'Get the kids inside, there's a bear out there,' " Erb said. No sooner had she herded the children into the pool building and closed the doors than one of the swimmer's mothers came running in.

"She said, 'I just saw a bear in the parking lot!' She told me a minivan of kids in the parking lot saw it too," Erb recalled in a phone interview yesterday.

Erb, 20, went out to get a look: "I saw something about three feet tall and black, moving--it was retreating into the bushes," she said. "It wasn't that impressive at the time. Then I thought about it and realized, 'I just saw a bear!' "

Local police and state wildlife officials, who say such sightings have become more frequent in communities north and west of Washington in recent years, were urging calm yesterday, noting that the bear has not been aggressive toward people and that it is not likely to be.

"Leave it alone, don't try to corner it--it will probably find its way through the area, head over to Sugarloaf Mountain or down towards the Potomac," said Steve Bittner, a forest game biologist for the Maryland Department of Natural Resources.

Experts say the Germantown bear seems to fit the profile of bears that typically venture into residential areas in late spring and early summer: a young male, about 200 pounds, 1 1/2 to 2 1/2 years old, sent out by its mother and seeking a habitat of its own.

During the last 10 years, officials say, there has been a mini-boom of reports of bears in the region, as the animals move from their traditional habitats in the mountains to new territory to the south and east on the fringes of Washington and other cities.

State officials estimate that 300 bears live in Maryland, primarily in Garrett and Allegany counties. Outside Garrett County, 82 bears were spotted in the state last year, just three of them in Montgomery County. They stopped counting in Garrett because bears were so numerous there.

"We've had sightings in Frederick this spring and in the last couple of weeks in Baltimore County," Bittner said. Last year, a black bear was spotted in Gaithersburg. The Ursus americanus, or black bear, by nature avoids people and tries to stay clear of civilization, Bittner said, though it has the capability of inflicting lethal injury.

The first bear sighting was phoned in to Montgomery County police on Thursday at 9:43 a.m., according to spokesman Derek Baliles. The bear was spotted by a motorist in a back yard on Water's Landing Drive between Anndyke Way and Spinning Wheel Drive. Homes there have back yards adjacent to Black Creek State Park.

The second call came from the swimming pool shortly after 10 a.m.

Before touring the pool area, the bear apparently made its way through other back yards. "My next-door neighbor's dog was going crazy," said Barbara Wallick, whose house is behind a community playground.

Wallick arrived at the pool moments after the bear had left but said she heard about it from the children and other parents.

"There's a fence around the pool and beyond that is the playground and [the bear] was right in there, next to the swings and the slide," said Wallick, who said no children were in the playground at the time.

Lifeguards sent the children home, and three Montgomery County police officers combed the bushes for the bear, to no avail.

A motorist saw the bear again yesterday about 7:30 a.m., roaming through front yards on Clarksburg Road near Little Seneca Lake.

Officials say they have no plans to pursue the animal. Unless he causes a problem, said Lauryn McNeil, of the Montgomery County National Capital Parks Police, "we're gonna let the bear be a bear."