Killer Whale Boat Attacks 'Getting Worse and Worse,' Scientist Says

The attacks on boats by three killer whales are "getting worse and worse," a scientist studying this unusual behavior has said.

Since the summer, sailors along the coasts of Spain and Portugal have reported killer whales ramming their boats, sometimes for hours on end. Other than a handful of reports, this behavior had not been reported before. Why they were targeting boats was unclear.

After more and more reports emerged of boats being rammed by orcas, Spanish authorities banned boats smaller than 49 feet from sailing through an area where attacks were being recorded. Footage from one attack can be viewed in the video above.

To better understand the killer whale behavior, several scientists came together to form an informal group looking at the events. They found most of the attacks were being carried out by three young orcas. After identifying these animals, which they named Gladis Black, Gladis White and Gladis Grey, they noticed the animals had suffered from injuries.

Whether these were from their encounters with boats, or if they were sustained before the attacks started, is not known.

Regardless, the encounters have continued. "It's getting worse and worse," Renaud de Stephanis, a biologist who is part of the team investigating, told the BBC.

Researchers say they do not think the killer whales are intending to cause damage or harm people on board, or that they are going after boats as a type of "revenge." Instead, they think it may be related to play.

Ruth Esteban, a researcher with the Coordinator for the Study of Marine Mammals (CEMMA), also involved in the investigation, told the BBC that the killer whales "always seem to go for the rudder." She said this may be because it is a mobile part of the boats.

"In some cases they can move the whole boat with it. We see, in some of the videos, the sailing boat turning almost 180 degrees," she said. "If they see that they have the power to move something really big, maybe that's really impressive for them."

"I've seen them hunting," Renaud said. "When they hunt, you don't hear or see them. They are stealthy, they sneak up on their prey. I've seen them attacking sperm whales. That's aggressive. But these guys, they are playing."

He said that from his observations of the encounters between these orcas and boats, it is mostly two of the three killer whales identified. "It's mainly two of those guys...that are just going crazy," he told the BBC. "They just play, play and play. And the game is getting worse and worse."

He said the behavior is concerning because of the impact it is having on vessels. "They love it," he is quoted as saying. "And don't know why. It just seems to be something they really like and that's it."

The working group is currently sharing information on the encounters and working with crews of boats to find out more about their experiences. They try to check vessels to understand how the killer whales are interacting with them, and looking out for sightings of the three culprits.

In October, Esteben told Newsweek the injuries the killer whales sustained appear to be healing. "I don't think they are causing them any major complications," she said. Killer whales normally stay in the Strait of Gibraltar over spring and summer. Whether the three juveniles will remain in the region or where they might go next is unknown, she said.

killer whale
Stock image showing killer whales. Scientists are studying the behavior of three orcas that have been ramming boats off the coasts of Spain and Portugal. iStock