Lynnette Bellin’s personal mission is to teach what she says is a “critical life skill”: swimming. She found out just how critical that skill was when desperately trying to escape a violent sea otter.

On Sunday, the infant swimming resource instructor was swimming along the east shore at Hidden Beach, a secluded public beach within Lake Tahoe-Nevada State Park, she posted on social media.

Bellin had been swimming for about 30 minutes when she felt something grab her leg.

The Times reached out to Bellin for comment but did not get a response before publication.

“I thought it was a person until I saw the otter, and then it kept coming at me with teeth and claws,” she said on Instagram. “I tried to push it away, but this thing was relentless.”

Video of the instructor after the attack shows her wearing a bright pink sun shirt, swim cap and swimsuit bottoms, and she is heavily splattered with blood.

Bellin has visible bloody lacerations to her nose, face, hand and legs.

During the attack, the woman swam toward a rock to get away from the animal, but she said the otter climbed onto the rock and continued to strike her.

“I finally climbed up on a bigger rock and got away from it, but it kept circling the area, so I knew I couldn’t get back in the water,” Bellin said on social media.

After successfully climbing over some large rocks and a fence, Bellin made her way to the East Shore Bike Trail and walked barefoot and injured back to the beach.

The Nevada Department of Wildlife was alerted of the attack just before 10 a.m., said Kenzie Margiott, a spokesperson for the agency.

Department staff searched for the otter to assess whether the animal was still in the area or displaying any abnormal or concerning behavior, Margiott said. But it had vanished from the area.

“Without locating and examining the animal,” she said, “we can’t determine what may have caused the reported aggressive behavior.”

Officials say otter attacks on people are uncommon.

River otters are native predators and found in Lake Tahoe and connected waterways all the way down to Pyramid Lake via the Truckee River, Margiott said.

Otters generally avoid people. But “an otter may act defensively if it feels threatened [or] cornered, protecting their pups and/or defending their hunting territory,” she added.

In a video on Instagram on Tuesday, Bellin said she was unsure of how to respond when people in her life asked if she was OK.

She said she felt the experience robbed her of her sanctuary. She is scratched and bruised and has had a total of 38 stitches, 22 of those in her right foot, which is swollen. But it seems to have cemented a core belief: Being a good swimmer can be a lifesaving skill.

Water, she said, can be unpredictable and unforgiving, and unexpected situations can arise.

“So being a competent, confident swimmer is really something everyone should know,” Bellin said.

She told KRON4 in San Francisco, “As I was being attacked, being a confident swimmer, I didn’t have to consciously think about my breath control or how to stay above water.

“[A]ll I had to do,” she said, “was think about fending off this animal.”