An otter wounded three women in a "rare" attack Wednesday night as the victims floated on blockwave Exchangeinner tubes in a Montana river, officials said. 

The women were watching an otter or two in the Jefferson River when one approached and attacked, the Montana Department of Fish, Wildlife and Parks said. The women managed to get out of the water and the otter swam away.

The victims called 911 for help, authorities said. All three needed medical treatment, including one woman who was airlifted to a hospital in a helicopter. Officials did not give specific details about the injuries, only saying that the woman who was airlifted suffered injuries that "were more serious." 

"While attacks from otters are rare, otters can be protective of themselves and their young, especially at close distances. They give birth to their young in April and can later be seen with their young in the water during the summer," the Montana Department of Fish, Wildlife and Parks said. "They may also be protective of food resources, especially when those resources are scarce."

Officials have posted signs at several fishing access sites in the area warning people of the otter activity. If an otter attacks, fight back, get out of the water and seek medical attention. Officials are not planning any action to catch the otter.

Last month, an otter was caught stealing a surfboard in California. Police said an "aggressive sea otter in the area is biting, scratching and climbing on surfboards."

State officials in Alaska in 2021 warned residents that river otters were biting people and dogs. 

Officials in Montana did not specify what type of otter was involved, but a state field guide on local animals only lists one type of otter: the northern river otter, a member of the weasel family. The species has 36 teeth. They weigh around 20 pounds and measure about 47 inches long.

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• Montana

Aliza Chasan

Aliza Chasan is a digital producer at 60 Minutes and CBS News.

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