After four years and hundreds of incidents, researchers remain puzzled why orcas, also known as killer whales, continue to ram boats – sinking a few of them – along the Iberian Peninsula.
The origin of these interactions remain a “great mystery,” said Alfredo López, a University of Santiago biologist, but he does not believe the behavior is aggressive. Orcas are large dolphins, López said. And like dolphins, the events could stem from the orcas’ curious and playful behavior, such as trying to race the boats.
López, who specializes in orcas, and his team, Grupo de trabajo Orca Atlántica (GOTA), have tracked these encounters since 2020. The team’s recent study theorizes the orcas could also be exhibiting cautionary behavior because of some previous traumatic incident.
Where have killer whales interacted with boats?
GOTA has tracked more than 350 interactions just on the Iberian Peninsula since 2020. Most have taken place along the Strait of Gibraltar, but the orcas’ mischief or self-defense may be spreading north. An incident was reported in June in the Shetland Islands in Scotland.
GOTA defines interactions as instances when orcas react to the presence of approaching boats, such as:
- Interaction without physical contact.
- Some physical contact without damage.
- Contact that causes serious damage that could prevent the navigation of the boat.
Recent incidents when orcas attacked boats and sank them
The most recent incident occurred on June 19 when an orca rammed a 7-ton yacht multiple times off the Shetland Islands in Scotland, according to an account from retired Dutch physicist Dr. Wim Rutten in the Guardian.
“Killer whales are capable of traveling large distances, so it is not out of the ordinary that an animal could travel that far,” said Tara Stevens, a marine scientist at CSA Ocean Sciences Inc. “To my knowledge, this data is not available, so we cannot confirm at this time if these are the same animals.”
Orcas have sunk three boats this year, one as recently as May, off the coasts of Portugal and Spain, but whale expert Anne Gordon told USA TODAY in May that the incidents shouldn’t heighten concerns about the whales.
“Yes, they’re killer whales. And yes, their job is to be predators in the ocean, but in normal circumstances there is absolutely zero threat to humans in a boat,” Gordon said.
Most of the interactions have involved sailboats, but fishing boats, semi-rigid boats and motorboats haven’t gone unscathed.
Are these the same killer whales attacking boats or unrelated incidents?
López hypothesizes that the interactions could be a self-induced behavior where you’re “inventing something new and repeat it. This behavior coincides with the profile of the juveniles.” He said it could also be response to an aversive situation: “One or several individuals had lived a bad experience and tried to stop the boat so as not to repeat it. This behavior coincides with the profile of adults.”
“Fifteen different orcas from at least three different communities” have been identified, López said. And they are probably teaching the habit to others, or the others are mimicking the behavior. “Without a doubt orcas learn by imitation,” López said. The majority of the culprits are juveniles that touch, push and sometimes turn the vessels. He noted that adult males don’t appear to be involved.
“Killer whales are incredibly intelligent animals that do learn behaviors from observation of other individuals,” Stevens said. “Typically, very unique behaviors such as this are learned ‘within’ group, meaning individuals of the group may learn from each other and participate, but that does not necessarily mean that the behavior is shared outside the group with other individuals.”
Which pods of killer whales are battering the boats?
Orcas operate in a social structure called a pod. These pods generally are a group of several generations of related orcas. Hierarchies are established within them, and they communicate and learn from one another, the study reads.
GOTA researchers have identified the individuals responsible for the interactions. One large pod is made up of three generations. It starts with grandmother Gladis Lamari, her daughter, grandchildren and a few other relatives.
Another pod comprises siblings Gladis Negra and Gladis Peque. Both have been photographed interacting with boats. Their mother, Gladis Herbille, has generally just watched her children at a distance from the boats, the study said.
A third group in the study are siblings and a cousin.
Orcas often tracking bluefin tuna
The movements of orcas depend on the location of their main food source, bluefin tuna. The migratory movements of tuna are very dynamic and predicting exactly where interactions will take place is very difficult, the report said. According to NOAA, Atlantic bluefin tuna are the largest in the tuna family and can reach a length of 13 feet and up to 2,000 pounds. They are a highly migratory species and can migrate thousands of miles across an entire ocean.
About the Iberian orcas
While they are called killer whales, orcas are actually the largest member of the dolphin family. This aquatic marine mammal family includes whales, dolphins and porpoises.
The Iberian orca is a subpopulation of the Atlantic orca population. These orcas are from the Strait of Gibraltar and the Gulf of Cádiz. Iberian orcas are small: 16 to 21 feet compared with Atlantic orcas that measure almost 30 feet.
Orcas in general are fast, reaching speeds up to 27.6 mph. By comparison, a 39-foot sailboat travels at about 9.2 mph.
What should you do if your boat is attacked by killer whales
The study recommended these tips to reduce the the duration and intensity of the interaction.
- Stop the boat.
- Leave the rudder loose.
- Keep calm.
- Radio for help.
According to the GOTA study, most of the vessels involved in interactions are medium-sized (less than 49 feet) sailboats, with a paddle rudder, sailing at an average of 6.9 mph, under both sail and motor.
The interactions have been mostly concentrated in the spring and summer months and have been concentrated in the midday hours. They’ve lasted on average for 40 minutes, but several last less than 30 minutes.
Types of rudders Iberian orcas have approached
“It is very common for dolphins to interact with the boats and approach,” López said. “Before 2020, the orcas did it with frequency but they weren’t classified as attacks. Now, sometimes they touch the boat and the encounter is unfairly classified as an attack. They judge socially before understanding what (orcas) do.”
