Why do killer whales attack boats?

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Last week, media reported that killer whales collided with a boat, causing it to sink in the Strait of Gibraltar between Spain and Morocco.

This incident is the latest in a series of attacks on boats by killer whales in recent years.

The accident occurred on May 12, and saw the sinking of a yacht called Alborán Cognac, according to the Spanish newspaper El País, and the crew members were rescued by a passing oil tanker.

In fact, attacks by killer whales, also known as orcas, on boats began around 2020, when a female killer whale known as “White Gladys” had a painful encounter with a boat, and then began to act defensively toward other boats.

This wave of killer whale attacks has scientists concerned about the animals' safety, and has led to speculation that these oceanic mammals may be trying to rise up against humans.

In a trend that some on social media have dubbed the “orca wars,” a group of killer whales recently collided with boats off the coast of Portugal and near the Strait of Gibraltar at a rate of about once a day.

According to researcher Rui Alves, who collects data on attacks, in June 2023 alone, there were 12 killer whale attacks on boats. In May, there were 21 attacks, according to his website orca.pt.

Researchers do not know exactly why these attacks occur, and how this behavior evolved, but they proposed two main hypotheses: The first is that killer whales, which are highly social and intelligent creatures, developed this new behavior, which is something that younger members are known to do.

The other, more worrying, possibility is that it is in response to a boat-related shock, as Dr. Alfredo Lopez Fernandez, of the Grupo Trabajo Orca Atlántica Foundation, or GTOA for short, said in a statement to the British newspaper The Guardian.

"It could be a response to a negative situation," he explained. "One or several whales have had a bad experience and are trying to stop the boats so it doesn't happen again." Pointing out that this behavior may have started with individual adult killer whales, but appears to be spreading through social learning.

If the latter possibility is correct, there is one prime suspect in starting this trend, a white orca named White Gladys (Gladys Blanca), who is believed to have been involved in a traumatic collision with a ship in 2020 when she was pregnant.

Lopez added that other killer whales in the area also suffer from injuries resulting from collisions with boats. “All this should make us think about the fact that human activities, even indirectly, are the origin of this behavior,” he said.

Back in 2020, a pod of killer whales was seen chasing boats in the area, in an aggressive act that was previously thought to be extremely rare. Since then, it has become more common. During attacks, killer whales' tactic is to damage or break the ship's rudder with their teeth, making it impossible to steer the boat and continue sailing.

Despite all the fears of continued killer whale attacks, researchers are more concerned that boat owners will attack the whales, or that killer whales will hurt themselves during collisions, as this group of Iberian orcas is threatened with extinction, according to the GTOA, with only 39 animals remaining. The last time a complete census was conducted was in 2011.