Killer whales teach their brethren to sink ships

Scientists believe that a wounded female killer whale initiated the attack on the boat and led smaller individuals to follow suit.

Female killer whales teach their younger calves to aim at the rudder. Photo: Chase Dekker — Female killer whales teach their younger calves to aim at the rudder. Photo: *Chase Dekker*

Killer whales have attacked and sunk a third cruise ship off the coast of Iberia, Europe. Experts believe the behavior is learned by other members of the group. Three killer whales ( Orcinus orca ) rammed the cruise ship on the night of May 4 in the Strait of Gibraltar, Spain, breaking the rudder. "There were two small killer whales and one larger one," said Captain Werner Schaufelberger. "The two smaller killer whales were aiming for the rudder at the back while the larger one kept charging at the side of the boat with all its might." Schaufelberger said he saw the smaller killer whales mimicking the larger ones. They observed the techniques of their fellows and also rammed the boat.

The Spanish coast guard rescued the crew and towed the boat to Barbate, but the vessel sank at the entrance to the harbor. Two days earlier, a pod of six killer whales had attacked another sailboat passing through the strait. Greg Blackburn, a sailor on the boat, saw the mother killer whale apparently teaching her calf how to aim at the rudder.

Reports of encounters with killer whales in the Iberian coast began in May 2020 and have become increasingly frequent, according to a study published in June 2022 in the journal Marine Mammal Science. The attacks are mainly on sailing vessels and follow a clear pattern: the pods approach from the stern to attack the rudder and lose interest after successfully stopping the vessel. The interactions have been ongoing since 2020 in areas where the killer whales live, including Galicia and Gibraltar, according to Alfredo López Fernandez, a biologist at the University of Aveiro in Portugal and representative of the Atlantic Orca Working Group.

Most encounters are harmless. Of the more than 500 interactions recorded since 2020, only three have resulted in sinkings. The spike in aggressive behavior toward boats is a recent phenomenon. Researchers believe that a traumatic event may trigger a behavioral change in killer whales, and the rest of the population may learn to imitate it. Experts suspect that the female killer whale, White Gladis, experienced a traumatic moment, a collision with a boat, or was trapped by illegal fishing, which led to the behavioral change. She was the one who initiated the direct contact with the boat.

Killer whales are highly social animals that can easily learn and imitate the behavior of others, according to a 2022 study. In most cases, killer whales will line up to the rudder of a boat and bite, bend, or break it. They appear to perceive this behavior as beneficial, despite the risk of crashing into a moving structure. Since the unusual interactions began in 2020, four killer whales from a small population in the Iberian Sea have died, although their deaths were not directly related to ship collisions.

Orca's unusual behavior can also be playful. They are extremely curious and playful animals, so interactions can be more like play than aggressive behavior, says Deborah Giles, a killer whale researcher at the University of Washington and the nonprofit Wild Orca.

As the number of accidents increases, experts are increasingly concerned about the safety of mariners and the Iberian killer whale population. In a 2011 survey, only 39 Iberian killer whales were recorded. “If this situation continues or worsens, it will pose a real threat to the safety of seafarers and the conservation of the endangered killer whale,” the team said.

An Khang (According to Smithsonian )

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