Three women were injured, with one woman needing to be airlifted to hospital, after an otter attacked them while they floated down a river on inner tubes.

The incident occurred on Wednesday evening at approximately 8:15 p.m. when the three friends were floating on inner tubes about three miles upstream from the Sappington Bridge in Montana, some 75 miles south of the state capital city of Helena, according to a statement released by Montana Fish, Wildlife & Parks on Thursday afternoon.

The women say they observed one or two otters while they floated down the river when one of them suddenly approached and attacked, causing the women to flee the water and the otter to swim away, authorities said.

“The women then called 911, and several agencies responded, including Montana Highway Patrol, Jefferson County Sheriff’s Office, Jefferson Valley Ambulance, and Montana Fish, Wildlife & Parks, Life Flight and a local landowner,” Montana FWP said.

All three women were injured in the sudden attack and received medical treatment in Bozeman, Montana -- approximately 45 miles east from where the incident took place.

One of the women was injured so seriously that she was airlifted by helicopter for emergency treatment after the animal attack, Montana FWP confirmed.

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

FWP staff have posted signs at several access sites to the river advising people in the region of otter activity. No further management action is planned at this time, authorities said.

“FWP advises recreationists to keep a wide distance, giving all wildlife plenty of space,” Montana FWP said. “In drought conditions, low water levels can bring recreationists closer to water-dwelling wildlife. Being aware and keeping your distance can help avoid dangerous encounters, reduce stress for wildlife, and promote healthy animal behavior.”

Said Montana FWP in a final warning to the public: “If you are attacked by an otter, fight back, get away and out of the water, and seek medical attention.”