Hollywood has produced depictions of animals banding together against humans – now some orcas seem like they’re turning fiction into reality.

Earlier this month, a boat was sunk after an attack by orcas off Europe’s Iberian coast, the third recent attack.

Three orcas, also known as killer whales, struck the yacht on the night of May 4 and pierced the rudder; Spanish coast guards rescued the crew and towed the boat to Barbate, but it sank at the port entrance.

“There were two smaller and one larger orca,” skipper Werner Schaufelberger told the German publication Yacht.

“The little ones shook the rudder at the back while the big one repeatedly backed up and rammed the ship with full force from the side.”

Mr Schaufelberger said he saw the smaller orcas imitate the larger one.

“The two little orcas observed the bigger one’s technique and, with a slight run-up, they too slammed into the boat.”

Attacks could be a learning curve

The sinking came just two days after a similar attack near Morocco in the same Strait of Gibraltar, where orcas repeatedly slammed into the hull of a boat, attempting to damage the rudder.

The orcas eventually lost interest, and the boat made it safely back to port with thousands of dollars of damage to the rudder and helm chains.

Sailor Greg Blackburn told Nine News the event didn’t feel malicious; instead, it looked like a learning experience.

“You can see in one of the videos the matriarch coming up and attacking the rudder with [a] calf at [the] side of her, then she drops back and then the little calf gets in to have a go,” he said.

“It was definitely some form of education, teaching going on.”

His experience echoed that of a French sailor on a boat that was attacked off the coast of Lisbon in 2022, leaving one of its two rudders destroyed.

Yann Krzemien thinks orcas were playing with his boat’s rudder. Photo: Facebook/Yann Krzemien 

“At the beginning, I was frightened because I thought they broke something on the hull,” French sailor Yann Krzemien said.

“[But] they were eating the rudder, quite softly … I realised they were not going to break anything.

“They were very calm, not aggressive. For me, it was like they were playing with the rudder. It was like a Chupa Chups for them.”

Motives under scrutiny

While some boat crews might not feel the orcas are being aggressive, scientists think the strange behaviour that has been on the rise since 2020 may have been sparked by a trauma response from a female orca known as White Gladis.

It’s believed White Gladis was left traumatised after suffering a painful collision or entrapment during illegal fishing, and has since been attacking boats, with other orcas copying her behaviour.

Assaults seem to be mainly directed at sailing boats and follow a clear pattern; orcas approach from the stern to strike the rudder, then lose interest once the boat has stopped.

The theory lines up with Mr Krzemien’s experience, as he noted in a Facebook post that the orcas left after the initial attack, but returned when the crew switched the boat engine back on. They only calmed down when the boat stopped again.

Alfredo López Fernandez, a biologist at the University of Aveiro, told Live Science he doesn’t think orcas are deliberately teaching their young to attack rudders, but the young are likely to imitate the adults’ behaviour.

Other scientists think the behaviour could just be a short-term fad, as seen with other orca pods that have been seen carrying dead salmon on their heads, or vocally mimicking sea lions.

Uprising is not imminent

While attacks are rising, they are still fairly rare.

“In more than 500 interaction events recorded since 2020 there are three sunken ships,” Dr López Fernandez said.

“We estimate that killer whales only touch one ship out of every hundred that sail through a location.”

There is some concern that the behaviour is dangerous both for sailors and the critically-endangered Iberian orca subpopulation.

A 2011 census recorded just 39 Iberian orcas, and four have died since the boat attacks began in 2020, although their deaths have not been directly linked with the boat encounters.