Orcas are attacking boats near Europe. It might be a fad.

Scientists don't know why Orcas are snapping the rudders off boats.

There have been strange encounters from the coast of Portugal to France. Several boats have been damaged by the orcas, but no one has been injured or killed.

A group of orcas rammed a sailboat belonging to a woman and her father off the coast of France. The pair were going to Madeira as part of a round-the-world sailing attempt when they were surrounded by killer whales. The cetaceans left behind a quarter of the sailboat's rudder. The father and daughter traveled to the French coast for repairs.

Scientists don't know why the orcas are going after rudders, but the incident near France was farther north than previous encounters, which have occurred near Spain and Portugal. According to a cetacean research group based in Spain, this suggests that more than one orca has picked up the behavior.

Orcas are similar to human fads in that they pick up behaviors from one another. Orcas in the Puget Sound began to wear dead salmon like hats. The trend was started by one female orca and spread through two other Pods. The orcas stopped putting salmon on their heads after about six weeks, but a few tried to bring it back the next summer.

The facts about killer whales are related.

Dolphins and orcas have fads as well. According to a study in the journal Biology Letters, a dolphin that was temporarily housed in a rehabilitation center as a calf may have led to the new trend of "tail walking". While being cared for by humans, the dolphin wasn't trained to tail walk, a move in which a dolphin raises most of its body out of the water vertically and skims backwards using its tail fin. The dolphins in the area spontaneously started tail walking a few years after the dolphin was tagged and released.

The director of Bay Cetology told NPR that orcas in the Pacific are playing with crab pots. Scientists don't know what attracts the European orcas to rudders. According to de Stephanis, it could be that they like the feeling of water being moved by a boat propeller.

De Stephanis said that when a boat's propeller isn't moving they break the rudder.

One boat-orca encounter occurred while the propeller was running. Maybe the orcas are interested in moving boat parts? De Stephanis thinks that the boat attacks are the work of some mischievous adolescents because juvenile males are often very curious and playful. The orcas will probably change their behavior if that is the case.

De Stephanis said this is a game. It will most likely stop when they have their own life.

It was originally published on Live Science