Orcas sink another boat in Europe after a nearly hour-long attack

A pod of orcas has attacked and sunk another boat in southwestern Europe after relentlessly bombarding the vessel and its crew for almost an hour on Halloween. It is the fourth time that orcas from this region's population have sunk a vessel in the last two years.

On Oct. 31, the Grazie Mamma — a mid-size sailing yacht owned by Polish cruise company Morskie Mile — was attacked by an unknown number of orcas for around 45 minutes off the coast of Morocco in the Strait of Gibraltar, Morskie Mile representatives wrote in a Facebook post translated from Polish.

The orcas (Orcinus orca), also known as killer whales, repeatedly hit the yacht's rudder causing major damage and allowing water into the vessel's hull. Despite receiving aid from the Moroccan Navy and being towed toward safety, the boat eventually sank as it entered the port of Tanger-Med in Morocco. All passengers were safely evacuated to rescue boats before the ship sank.

The unusual attack is the latest example of one of many unnerving new orca behaviors that have highlighted the striking intelligence of these deadly predators. 

Related: 11 ways orcas show their terrifying intelligence 

Since 2020, orcas have been regularly harassing boats in the Strait of Gibraltar — a narrow strait between Spain and Morocco that connects the Atlantic Ocean to the Mediterranean Sea — and the surrounding waters off the coast of the Iberian peninsula. 

These nautical raids were likely started by a pod including White Gladis, a female orca who may have been traumatized by a past boat collision. The unusual behavior then spread among other individuals who seem to be becoming more daring and efficient with their attacks.

So far, at least three other boats have been sunk in the area, with the most recent incident occurring in May 2023 and the previous two both occurring in 2022. And in June, a yacht had its rudder ripped clean off with "ruthless efficiency" in a 15-minute attack. 

Researchers suspect that orcas are learning to attack boats from one another. Witnesses have also reported seeing orcas "teach" other individuals how to maximize the damage they cause, Live Science previously reported.

Related: How often do orcas attack humans?

So far, only one other boat has been attacked outside of the Strait of Gibraltar and its surrounding waters: A yacht in Scotland, more than 2,000 miles (3,200 kilometers) away, which was rammed by a lone individual. However, it is impossible to directly link this attack to the other orcas. 

Boat attacks are not the only unusual learned orca behavior that scientists have taken note of in recent years. 

Since 2017, a pair of orcas known as Port and Starboard have killed dozens of great white sharks in South Africa by ripping out their livers. And on Oct. 17 this year, this behavior was also documented in Australia for the first time, hinting it may also be spreading.