A woman swimming in the lake at Bear Creek Village was the victim of an attack so rare that wildlife officials aren't certain on a cause.

She was swimming in the lake on the evening of Aug. 17 when she was bitten three times on the legs by a river otter, according to Game Commission wildlife conservation officer Phil White, who investigated the incident.

The otter followed and bit the swimmer as she made her way to shore and then left once she exited the lake, White said.

White, who declined to release the victim's name, said the swimmer sought treatment for her injuries and received a rabies vaccination as a precaution. Otters aren't uncommon in the area, White said, and the primarily aquatic animals travel through Bear Creek Village on their way to the Francis E. Walter Reservoir.

What is unusual, White added, is for an otter to attack a human.

"This is not normal behavior for an otter," he said. "It just goes to show how unpredictable wildlife can be."

Tom Hardisky, a wildlife biologist with the Game Commission, said he is aware of just two other otter attacks on people — one in 2002 in the southeast part of the state and another in Florida in the 1980s. The otters in both instances tested positive for rabies.

"These unprovoked attacks are almost unheard of," Hardisky said. "It's very strange, abnormal behavior for an otter. Maybe it was rabies or a mother with young ones. I can't explain it."

According to statistics from the state Department of Agriculture, there have been only two confirmed cases of an otter with rabies in Pennsylvania since 1944 — one in 1992 and another in 2002.

While it isn't known if the otter that attacked the swimmer in Bear Creek Village was rabid, there was discussion about trapping the animal to have it tested.

Paul Updike, president of the Bear Creek Association, said he spoke to three trappers about the feasibility of capturing the otter, and they all said there was no way to specifically target the animal responsible for the attack.

"They said it's an unusually rare occurrence and the odds are very low it would happen again," Updike said. "The trappers said if the otter or otters are removed, others would take its place."

Updike said the association doesn't regulate or control the lake itself so it's not an issue they would address, but he added the group was never in favor of removing otters from the lake.

He said the swimmer reported being attacked by a single otter, but the following weekend a group of three otters was spotted in the lake.

"It's been quiet since then. There hasn't been a lot of activity with otters," Updike said, adding the incident hasn't had a major impact on people using the lake.

"I swam in the lake that weekend. You just have to be aware."

Kevin Wenner, a Game Commission biologist for the northeast region, agreed that attempting to trap the otter wasn't feasible because there's no way to determine if any animals removed were responsible for the attack.

He said other than a beaver with rabies that attacked several people in Philadelphia in 2011, conflicts with aquatic mammals are extremely rare.

Wenner added the incident is no reason for people to avoid using the lake.

"Just use caution. There's always been otters in that lake for decades and there hasn't been an issue until now," he said.