Killer Whales Filmed Attacking Yacht in 'Scary' Encounter Lasting Two Hours

A video of killer whales attacking a yacht off the coast of Portugal has been released by the company delivering the vessel. Footage shows the killer whales, also known as orcas, ramming the boat in what the narrator calls "quite an ordeal."

Pete Green, from U.K.-based yacht delivery company Halcyon Yachts—International Yacht Delivery, said two crew members and the two owners of the 45-foot boat were on board when the attack took place on October 4.

They were sailing off the coast of Porto on their way to Gibraltar when they saw what they initially thought were dolphins jumping from the water. However, as the animals got closer, they realized they were killer whales.

"They got closer and closer," Green, who was not on board but whose company was delivering the yacht, told Newsweek. "You can hear in the film them ramming the rudder and hitting the boat."

"It was fairly playful, just bumping the rudders. No serious damage was done. It lasted about two hours in total. It was more harassment, several bumps, sometimes they'd hit the rudder that would affect the steering so they'd start going in circles."

Killer whales have been attacking boats off the coast of Portugal and Spain in recent months, with reports of attacks dating back as early as July. Most of the attacks are believed to have been carried out by three juvenile killer whales, scientists analyzing their behavior have said.

What has prompted the behavior is unknown. Researchers say the three animals show signs of injury, but it is unclear whether this was the result of interactions with the boats or whether they were hurt before the attacks began.

Green said this is the second yacht his company has been delivering that has been involved in an attack, with the first having taken place on September 11. In this event, the boat lost its steering and had to be towed in. Footage from this attack can be seen below.

In the latest incident, the crew contacted the coast guard, who told them to turn off the boat's systems and just sail. "They were lucky for the rudders not to break," Green said. "The orcas are pretty powerful. If they'd wanted to do some damage they could've done far worse.

"I don't think [those on-board] ever felt under true threat. They were OK. It was definitely a scary experience."

Ruth Esteban, a researcher with the Coordinator for the Study of Marine Mammals (CEMMA), who is analyzing the killer whale behavior, told Newsweek it is still unclear why the killer whales are targeting boats along this stretch of coastline. She said the attacks are ongoing, although since Spain banned smaller boats from sailing in high-risk areas, incidents have become less frequent.

"Either is just simple curiosity of young individuals, or it was something that was triggered by some adverse situation with a vessel," she said. The researchers do not have evidence to show whether the wounds were caused before the behavior began, or whether the wounds were caused by the behavior.

Green, who has worked in the industry for 20 years, says they are still moving boats along this coast and they do not consider the killer whales to pose a serious risk. "The worry is if more pods start doing it," he said. "I've never heard of this happening along this coast. Even seeing orca is rare, never mind them attacking. This is the worrying thing, if it's a new behavior they've developed for some reason. I think people are thinking there is one pod in particular doing this, but we don't know why."

Stock image showing two orcas. One of the latest attacks by killer whales on boats off the coast of Spain and Portugal was filmed by the crew on board. iStock