Killer whales are said to be teaching one another how to sink boats after a British couple were attacked on holiday.
The shocking marine attacks seemingly began in May 2020, in the Mediterranean.
Scientists are said to believe that a single traumatised orca began the vicious assaults on boats.
This was said to happen after a “critical moment of agony” but the behaviour is now spreading through the killer whale population as they learn from one another.
Just this week a British couple from Cambridge had been enjoying sailing in the Mediterranean near Morocco when they were set upon by six killer whales.
Janet Morris and Stephen Bidwell, both 58, had been taking sailing lessons when the incident occurred.
Similar to other attacks, the raucous orcas slammed into the boat during an attack that lasted around an hour in choppy conditions.
Earlier this month, a mirror attack took place in the Strait of Gibraltar.
Three orcas set upon a yacht and struck and damaged the rudder - something that’s been seen across other attacks.
Skipper Werner Schaufelberger told the German publication Yacht: "There were two smaller and one larger orca.
"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."
But then what happened chilled the skipper as he saw the smaller orcas imitate and copy the larger one.
He added: "The two little orcas observed the bigger one's technique and, with a slight run-up, they too slammed into the boat.
Spanish coast guards rescued the terrified crew and tried to get the boat too but it sank as they towed it into port.
Then, just two days before that, a pod of six orcas sprung a sudden attack on a sailboat in a similar area.
Greg Blackburn,an experienced sailor from Leeds, was on board at the time and looked on as a mother orca seemingly taught her calf how to take out the rudder.
Speaking to 9news, he said: ""You can see in one of the videos the matriarch coming up and attacking the rudder with calf at side of her, then she drops back and then the little calf gets in to have a go.
“It was definitely some form of education, teaching going on."
Reports of aggressive orcas trying to sink ships seemingly began to become more frequent around early 2020, a study published in the journal Marine Mammal Science, warned.
The study outlined how the attacks are generally directed at sailing boats and follow a clear pattern.
Orcas approach from behind and strike the rudder until it breaks, but have no interest in the people on board seemingly.
In the paper, entitled ‘Killer whales of the Strait of Gibraltar, an endangered subpopulation showing a disruptive behavior’ co-author Alfredo López Fernandez, a biologist at the University of Aveiro in Portugal, said: "The reports of interactions have been continuous since 2020 in places where orcas are found, either in Galicia or in the Strait.”
Speaking to Live Science, he added: "The orcas are doing this on purpose, of course, we don't know the origin or the motivation, but defensive behavior based on trauma, as the origin of all this, gains more strength for us every day.
Experts believe that a female orca they call White Gladis suffered a "critical moment of agony".
This could be a collision with a boat or getting trapped during illegal fishing and it that flipped a behavioural switch "that traumatised orca is the one that started this behaviour of physical contact with the boat.”
Orcas are incredibly social creatures that can easily learn and reproduce the behaviours of others.
Lopez said that orcas weren’t teaching the young directly but the behaviour was spreading by imitation.
