Marine scientists have been documenting something highly unusual over the past three years: numerous incidents of killer whales attacking small boats. As reported by Stephanie Pappas for Scientific American, these incidents have all occurred in the same general vicinity, off the Portuguese and Spanish southern coasts.
A trio of orcas attacked a boat in the Strait of Gibraltar earlier this month, damaging it so badly that it sank soon afterward.
The May 4 incident was the third time killer whales (Orcinus orca) have sunk a vessel off the coasts of Portugal and Spain in the past three years. The subpopulation of orcas in this region began harassing boats, most often by biting at their rudder, in 2020. Almost 20 percent of these attacks caused enough damage to disable the vessels, says Alfredo López, an orca researcher at the Atlantic Orca Working Group (GTOA), which monitors the Iberian killer whale population. “It is a rare behavior that has only been detected in this part of the world,” he says.
As Pappas reports, the GTOA has documented 505 incidents where killer whales were seen in this region either approaching or, more rarely, making physical contact with watercraft, often disabling them by biting off their rudders. 24 boats have been badly damaged in the Strait this year alone. Significantly, however, in those incidents where the boat actually sank there have been no “clean-up” attacks on the floundering passengers or operators themselves. As reported by LiveScience:
Assaults seem to be mainly directed at sailing boats and follow a clear pattern, with orcas approaching from the stern to strike the rudder, then losing interest once they have successfully stopped the boat.
It almost appears the orcas may be collectively performing some type of organized protest on boatowners, one designed to vent their displeasure more than anything else.
Researchers aren’t sure why the orcas are going after the watercraft. There are two
hypotheses, according to López. One is that the killer whales have invented a new fad, something that subpopulations of these members of the dolphin family are known to do. Much as in humans, orca fads are often spearheaded by juveniles, López says. Alternatively, the attacks may be a response to a bad past experience involving a boat.
The Iberian orca population is small and endangered, made up of about 39 animals as of the last census count (in 2011), which allows for fairly comprehensive observation of them (other sources report 63 recorded orcas migrating regularly into the Strait). And in fact, there is evidence that these attacks are being orchestrated by a gleeful gang of young orcas, possibly at the behest of an older female who may have trained them. In 2020 attacks were observed by a group consisting of a “trio of juveniles, occasionally joined by a fourth” and another group involving an adult female possibly disgruntled by a prior bad experience (in which she was injured by a fishing net), along with “two of her young offspring and two of her sisters.” The orcas migrate to the area from the coast of Portugal to hunt bluefin tuna. All of them have apparently had plenty of time to nurse their grievances at the intrusive vessels floating above their territory.
One of the passengers from a boat recently sunk by the orcas provided a colorful description of the incident to the Daily Mail:
One of the crew of four who survived the relentless two-hour attack, April Boyes, a 31-year-old sailor from Manchester, saw the orcas at such close quarters, she tells me, that she could see into their dinner plate-sized eyes and hear them snorting through their blowholes as they disabled the yacht with mighty headbutts and bites, then swam around it as if admiring their work.
Still, as David Jones (yes, that’s his name!) writing for that publication, observes, “Beyond the cruel confines of the grim marine parks to which some are consigned, these supreme predators — which can hunt and devour a great white shark — have seldom injured anyone, and wild orcas are never known to have killed a human being.”
Even with this comforting knowledge, however, pleasure craft and yacht owners are now re-thinking their ventures into the straits of Gibraltar, lest they be left bobbing haplessly in their lifejackets while scenes like this unfold around them:
'When the attack was over, the orcas started playing with a broken-off piece of rudder, throwing it around between them.
'Then one of the bigger orcas balanced the rudder on top of a baby's head and baby swam off with it, like it was a trophy.
Scientists speculate that the injured female (nicknamed “White Gladis” by local fishermen and whale watchers, though not by scientists) may have trained her own young and immediate relatives in the to attack boats following her own injury. Others have dismissed the idea that the incidents are rooted in some type of retaliatory motivation, pointing out that young orcas may just be “playing around.”
Because orcas have their own unique type of “social media.” As reported by Dino Grandoni for the Washington Post:
After learning a new behavior, juvenile orcas often keep repeating it ad nauseam. (In that way, they are a lot like human youngsters.) Playing around is just a part of learning how to be an apex predator.
Under either theory, however, once the kids got the message that it was “cool” to attack boats, all hell apparently broke loose.
Orcas, like humans, also get hooked on fads. They learn behaviors from each other, specifically from younger orcas. That learned behavior can spread around a pod and even between pods; three separate pods of orcas carried dead salmon on their heads for a few weeks in 1987.
Apparently, even for killer whales, once an idea goes viral, there’s not much you can do to stop it.