Three women were attacked by an otter in Montana on Wednesday evening, leaving one victim so seriously injured that she needed to be airlifted to the hospital, authorities said. The incident took place at around 8:15 p.m. as the women floated down the Jefferson River on inner tubes. The group spotted “one or two otters” before one of the animals swam over and attacked them. It wasn’t until the women got out of the water that the otter left them alone, Montana Department of Fish, Wildlife and Parks said in a statement. All of the group needed medical treatment, and one was flown to a hospital by helicopter. “While attacks from otters are rare, otters can be protective of themselves and their young, especially at close distances,” the statement added. Authorities also advised people to give “all wildlife plenty of space.”