Why the attacks may have started
A recent paper in the journal Marine Mammal Science found that the attacks involved nine whales in two groups: a trio, sometimes a quartet, of juveniles; and a mixed-age group led by a mature female named White Gladis. Given that White Gladis was the only mature female involved, the paper’s authors speculated that she had been involved in an accident with a boat and engaged in retributive behavior, which was then copied by the younger whales.
When it started happening, I did think that maybe a female or her calf had been nicked by a propeller or rudder on a boat, because every single time they seem to go for the rudder. And it’s all on sailboats.
However, not everyone is convinced that the orcas’ actions have any malevolent intent. Notably, the orcas’ focus is very specifically on the boats; none have shown any interest in the people on board, even when those people have had to scramble into lifeboats when their vessels started sinking. Some think it’s just as reasonable to suggest that they’re doing this because they can, because it’s fun.
A new form of play
Strager spoke to a biologist who was on board the boat that sunk in November, “and he said, ‘We didn’t feel any aggression.’ And, to me, that’s actually a strong testimony. Because I think when you are interacting regularly with animals, and you’re used to reading them, you can feel an aggressive intent, and they didn’t.”
If the orcas are indeed playing, it may suggest that, in time, the boat attacks could end when the whales get bored. Orca populations around the world have been observed engaging in a new behavior for no obvious reason than that they appear to enjoy it and then, just as suddenly, dropping it and moving onto something else. Orca researchers call these play routines “fads.”
Olsen, for example, has observed killer whales off Alaska playing with a piece of kelp for an hour: dragging it around on their fins, dropping it, circling back around and then picking it up in their teeth and swimming around with it some more. Strager has observed similar behaviors in orcas off the coast of Norway.
“For a while we saw them playing around with jellyfish,” she says. “They would swim with them on their snouts and would try to keep them on for as long as possible.”
There’s no benefit from this behavior, and the orcas were not eating the jellyfish, Strager notes.
“Sometimes we also see them whack little auks … small Arctic birds, they just lie on the surface of the sea to rest, and the orcas will come and whack them,” which she thinks is also a form of play.
Olsen questions whether we will ever truly understand the motivation behind the behavior, or whether we even really have the capacity to figure it out.
The whale brain has been evolving separately for 50 million years. It’s hard to get a whale into an MRI, we don’t even know which parts of the brain are dedicated to which activity. It’s hard enough for us to explain behavior in humans and in primates that are closely related to us.
Facing retaliation
Only this population has shown any interest in attacking boats, and it is a small one: the Marine Mammal Science paper cited an estimate of just 39 individuals.
The population in this region is under threat from tuna fishing, pollution, noise and, indeed, ship strikes. They are among the most polluted marine mammals in the world, so their breeding success is not good. It’s a very stressful environment for them..
And now, added to the existing stressors is the prospect of retaliation. Now they are becoming feared in the area, and there are reports of people suggesting you should pour diesel on top of them if they attack your boat, that you should put firecrackers in the water or ignite dynamite. I understand if people are afraid. But it’s really a very dangerous situation for the killer whales.
One local group, the Atlantic Orca Working Group, catalogues interactions between whales and boats so that sailors can learn which areas to avoid.
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Watch orcas team up to hunt great white sharks in rare video
The killer whales ripped the liver out of a shark and passed it around—only the second time orcas have been seen engaging in this behavior.
A pod of killer whales chased a young great white shark, immobilized it and then bit its liver out of its body. Researchers documented this rare interaction in the journal Frontiers in Marine Science, representing what they say is the first example of this behavior in the Gulf of California and the second worldwide.
The study adds to a growing body of research on killer whales, also called orcas, hunting great white sharks.
“The footage that they’ve gotten for this study is incredible,’’ says Isabella Reeves, a predator biologist at Flinders University in Adelaide, Australia, who was not involved in the research. Especially is rare is the depiction of the whales sharing the prey with each other, she says: “There’s very few high-quality instances where we actually see that occurring, especially documented to this extent.”
In the Gulf of California, the body of water that separates the Baja California peninsula from Mexico’s mainland, marine biologists Erick Higuera, Francesca Pancaldi, and their team have closely studied a group of killer whales since 2018. They call it “Moctezuma’s pod,” after one of the individual whales that was first spotted in 1992 and was nicknamed for the Aztec emperor.
Over the years, they observed these orcas using diverse strategies to hunt a vast array of prey: from rays to whale sharks, stingrays and bull sharks.
Documenting the hunt
In August 2020, while the team was out at sea following the pod to conduct their research, the killer whales started hunting. Higuera quickly flew his drone to record the action.
Just days later, after downloading the footage, Higuera realized that the pod he recorded was hunting something unexpected: young great white sharks.
To hunt a juvenile great white shark—which is usually around 6.5 feet long—the killer whales would run it down, bite it and try to flip it on its back. In this position, the shark would become paralyzed, making it easier for the whales to bite their prey without being bitten back.
The members of the pod would take turns keeping the shark belly up, and toward the end of the attack they would bring it underwater. After about two minutes they would reappear, and one of the killer whales would hold the shark’s fatty, calorie-rich liver in its mouth.
The team recorded the Moctezuma’s pod again in August 2022, hunting one young great white shark in the same location where they spotted the first two predations. This time, the team didn’t see the orcas turning the shark upside down to kill it.
‘’The footage gives us a very clear look at how the interaction unfolds, which we’ve only been able to document directly in a few places globally,” says Alison Towner, a marine biologist at Rhodes University in South Africa who wasn’t involved in the new study.
(Why are these orcas killing sharks and removing their livers?)
Putting the behavior in context
Orcas have been documented hunting great white sharks in other parts of the world such as New Zealand, California and South Africa. They have mainly been seen hunting adults—which are 13 to 16 feet long—and studies in some areas showed that when one individual is hunted by killer whales, all the others move away from that area en masse to avoid the predators.
In this case, the Moctezuma’s pod seems to be targeting juveniles, say Higuera. ‘’They might be coming to this particular spot where we saw them just to hunt juvenile great whites,’’ which are probably easier to hunt, as “more naive than adult great whites,” he says, and might not know how to escape killer whales—which are their only predator. ‘’But I couldn’t doubt that they also hunt semi adults and adult great whites in this area, it’s just that we haven’t seen it yet.’’
Climate change may also be playing its part in this rare interaction. Scientists say that due to warming waters and other factors, the nurseries of these sharks might be moving—with great whites increasing their presence in the Gulf of California, presenting the orcas living there with a juicy opportunity to hunt them.
But Reeves notes that it’s too soon to draw conclusions on the effects that killer whales might have on the great white sharks living in that area. “It’s complex, and we can’t risk oversimplifying these interactions,” she says.
On the other hand, Towner, who wrote her doctoral dissertation on orcas displacing white sharks in South Africa, says the behavior could become a problem for great white sharks populations, especially if it becomes frequent.
‘’White sharks are slow to mature, long-lived, and produce few offspring, so they’re vulnerable to added pressures,” she says. In South Africa, for example, white sharks have left sites where they congregate in large numbers because of attacks from killer whales. ‘’That displacement can move them into areas where the risks from fisheries or shark control gear are higher—so the indirect effects matter as much as the predation itself.’’
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AN ORCA POD HUNTS A PYGMY SPERM WHALE
Whale watchers in Madeira captured the astonishing moment orcas took down the deep-diving marine mammal. The predatory behavior had never been documented in the region. A pygmy sperm whale was attacked by a pod of orcas off the coast of Madeira. Orcas preying on marine mammals are rarely seen in the region.
By Melissa Hobson
December 2, 2025 NATIONAL GEOGRAPHIC
As the whale watching boat slowly approached, the passengers saw something strange in the water—an 80-foot cloud of red-brown liquid. Just minutes later, an orca hurled a small whale into the air. Dark red fluid gushed from its body. A member of the three-orca pod forced the whale under the water, holding the thrashing animal below the surface.
One of the orcas then approached the boat with its prey in its mouth, and then she looks at us like, hey, look what I got? They never thought for a second it was going to be a mammal.
What Dávila Pardo didn’t know at the time was that she may have documented the first known instance of orcas hunting a marine mammal in Madeira, a Portuguese island territory in the northeast Atlantic Ocean. Dávila Pardo recently published her account of the whale attack in the journal Marine Mammal Science where she and her coauthors noted finding no other examples of such behavior in the region. However, it’s the fourth global record of orcas hunting pygmy sperm whales.
A unique self-defense strategy
When they saw the picture for the first time, they thought “oh my God, that’s blood. It was very dark,
But it wasn’t blood. When pygmy sperm whales feel threatened, they release a reddish intestinal fluid as a form of self-defense. Like a squid’s ink, this substance obscures the whale, giving it a chance to get away.
But it didn’t work on the orcas. With the killer whale’s sophisticated echolocation, it’s like having a military submarine tracking you.
Pygmy sperm whales are deep diving animals that live far from shore so are rarely seen by humans.
They prefer offshore habitats usually in waters of 400 meters (1,300 feet) or more. These orcas, as apex predators, have developed a coordinated foraging strategy that can efficiently target this deep-water species.
Killer whales are only seen around Madeira a handful of times each year, and not much is known about the local population. Although orcas had been recorded hunting whales and dolphins in the nearby Azores and the Canary Islands, the video of such a rare event in Madeira still surprised scientists.
Neither Lott nor de Stephanis are aware of previous records of killer whales hunting pygmy sperm whales in Madeira.
Understanding a mysterious predator
When they spotted the three individuals earlier that day, they thought they might start hunting. There’s no reason for these animals to stay this long. More clues soon started to emerge.
Dávila Pardo had never heard of pilot whales and beaked whales interacting, but she’d also seen the two species together earlier that same day.
“I said, ‘maybe there’s something bigger in the area, and that’s why the beaked whales are trying to defend themselves by finding shelter with the pilots’,” she says. Pilot whales have previously been seen swimming after orcas, perhaps to scare them off. The gruesome hunting scene followed shortly after.
Around the world, there are several distinct types of orcas—known as ecotypes—that have different appearances, behaviors, and prey. Many eat fish, offshore killer whales have been recorded hunting sharks, and orcas in the Pacific Northwest are best known for hunting and eating mammals like seals.
Evidence that the Madeira population also eats mammals is “just a fascinating discovery,” says de Stephanis. He had heard theories that orcas in the area might feed on marine mammals, but this confirmation, and that they attack deep diving species, was particularly surprising.
Lott was surprised that the three individual orcas weren’t found in photo identification databases from the Madeira Whale Museum and the citizen science program Happywhale, which might suggest they are a transient pod. “Adding these ‘mystery orcas’ to the literature will contribute to a larger scale understanding of orca movement,” he says.
If killer whales in Madeira are hunting mammals, it might also spell trouble for the island’s critically endangered monk seals of which there are fewer than 30 adults. Are we looking into something that could possibly be a problem for this population?
To answer this and additional remaining questions, she says she and other local experts need more observations of their behavior. By sharing her paper, she wants to get out the message: “these are our orcas. Have you guys seen them around? We need help.”