SAN FRANCISCO -- A sea lion bit a swimmer in the waters of San Francisco's Aquatic Park early Thursday -- the fourth such attack in those waters in less than a month, CBS SF Bay Area reports. The woman suffered a non-life threatening bite to the leg, the San Francisco Fire Department said.

She was taken to a local hospital by ambulance after the attack, which happened just before 7 a.m., according to a spokeswoman at the Dolphin Swim and Boat Club.

In mid-December, three swimmers were attacked by sea lions in separate incidents in the span of a week, and officials with the San Francisco Maritime National Historical Park temporarily prohibited swimming in the popular cove.

The December attacks sent a chill through the well established community of swimmers who take to the cold-water cove daily. Among them was Rick Mulvihill, who suffered a severe bite in December.

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"I was just swimming along and whatever it was -- everybody's thinking it's a sea lion now; I never saw him -- came up from underneath me and hit me. It's like being in a car accident," Mulvihill said last month.

The large sea mammal clamped its teeth down onto Mulvihill's groin area. When it finally let go, he put pressure on the wound as he backstroked 1,000 yards to his swim club, using one arm.

His friend and fellow swimmer Joe Boone helped him onto the beach.

"So I looked and I said, 'We're gonna call 911.' Because I could see ... there was no blood whatsoever, but I could just see there were deep wounds there," said Boone.

Mulvihill was rushed to the hospital to have his wounds checked and he was treated to prevent rabies. He believes the cold water saved him from massive blood loss. He's shaken, knowing that if the bite had hit his femoral artery, it could have killed him.

While sea lions are occasionally seen in Aquatic Park, swimmers there are alarmed by the recent aggressive behavior of the animals living nearby.

"We've seen sea lions come through Aquatic Park. We've never seen them consistently swimming around," said Boone. "So that's a new thing, and that's an issue. And I think sea lions at Pier 39 are a problem."