July 10, 2023
Ana M. Lopez

Why are orcas attacking boats and sometimes sinking them?

Researchers are still trying to understand why orcas, also known as killer whales, have been ramming boats and even causing some to sink along the Iberian Peninsula. Despite studying these incidents for four years and documenting hundreds of them, the origin of these interactions remains a "great mystery," according to Alfredo López, a biologist from the University of Santiago. However, López believes that the behavior of orcas is not aggressive. He points out that orcas are large dolphins and suggests that the events could be a result of their curious and playful nature, possibly trying to race the boats. López, along with his team called Grupo de trabajo Orca Atlántica (GOTA), has been tracking these encounters since 2020. Their recent study suggests that the orcas might also be displaying cautious behavior due to some previous traumatic incident.

GOTA has observed over 350 occurrences of interaction solely on the Iberian Peninsula since 2020. The majority of these incidents have taken place near the Strait of Gibraltar, but it is possible that the mischievous orcas or their acts of self-defense are spreading northward. In June, there was a reported incident in the Shetland Islands in Scotland.

The most recent occurrence took place on June 19. According to a report from retired Dutch physicist Dr. Wim Rutten in the Guardian, an orca repeatedly collided with a 7-ton yacht near the Shetland Islands in Scotland.

Orcas have caused three boats to sink this year, with the most recent incident occurring in May, off the coasts of Portugal and Spain. However, whale expert Anne Gordon reassured USA TODAY that these incidents should not raise concerns about the whales.

According to Gordon, although killer whales are predators in the ocean, there is absolutely no threat to humans in a boat under normal circumstances.

López suggests that the interactions may be a behavior that individuals create and repeat. This behavior is common among young individuals. He also mentions that it could be a response to a negative situation. One or more individuals may have had a bad experience and are trying to prevent it from happening again. This behavior is typical among adults.

Fifteen different killer whales from at least three separate communities have been identified, according to López. It is likely that they are teaching this behavior to others or that others are imitating them. Orcas definitely learn by imitating, López confirmed. Most of the culprits are young whales who touch, push, and sometimes turn the boats. It seems that adult males are not involved in these actions.

Tara Stevens, a marine scientist at CSA Ocean Sciences Inc, stated that killer whales are highly intelligent creatures that learn behaviors by observing other individuals. Usually, these unique behaviors are learned within a specific group, meaning that individuals within the group learn from each other and participate. However, this does not necessarily mean that the behavior is shared outside the group with other individuals.

Orcas live in a social group called a pod. These pods usually consist of multiple generations of related orcas. Within these groups, hierarchies are established and they communicate and learn from each other, according to the study.

The location of the main food source for orcas, bluefin tuna, determines their movements. The movements of tuna are constantly changing, making it difficult to predict where interactions between orcas and tuna will occur, according to the report. These tuna are known for their extensive migrations, traveling thousands of miles across entire oceans.

Orcas, also known as killer whales, are the biggest type of dolphin. They belong to a group of marine mammals that includes whales, dolphins, and porpoises. The Iberian orca is a specific subgroup of orcas that live in the Atlantic Ocean. These orcas can be found in the Strait of Gibraltar and the Gulf of Cádiz. Compared to other Atlantic orcas that can grow up to almost 30 feet long, Iberian orcas are relatively small, measuring between 16 to 21 feet.

In terms of speed, orcas are quite fast, reaching speeds of up to 27.6 mph. For comparison, a sailboat that is 39 feet long travels at approximately 9.2mph.

According to López, it is a frequent occurrence for dolphins to engage with boats and come closer to them. Prior to 2020, orcas also used to do this quite often, but it was not considered as attacks. Nowadays, there are instances where orcas make contact with boats, and these encounters are mistakenly labeled as attacks. López suggests that they should be evaluated based on social behavior rather than assuming malicious intent.