In March 2019, researchers off the coast of southwest Australia witnessed a horrifying scene as a dozen killer whales swooped down to kill one of the largest creatures on Earth. Killer whales ate huge chunks of meat from the sides of an adult blue whale, which died an hour later. This was the first documented case of killer whales attacking blue whales, but not the last.
In recent months, killer whales (Orcinus killer whale) were also noticed abduction of pilot whale cubs and tear sharks apart to eat their livers. And off the coast of Spain and Portugal there is a small population killer whales began to ram and sink boats.
They have parts of the brain associated with memory and emotion that are significantly more developed than even the human brain.
It's unlikely that killer whales' brains change at an anatomical level, he says. Josh McInnesmarine ecologist who studies killer whales at the University of British Columbia. “Behavior Change Maybe influence the anatomical changes of an animal or population,” but only over thousands of years of evolution, McInnes told Live Science.
But killer whales are quick learners, which means they can teach each other some terrifying tricks and thus become “smarter” as a group. However, some of these seemingly new tricks may actually be ancient behaviors that people are only now documenting. And, just like with humans, some of these learned behaviors become trends, ebb and flow in the social waves.
Frequent interaction with people during boating and fishing may also encourage killer whales to learn new behaviors. And the more their environment changes, the faster orcas must react and rely on social learning to survive.
Hunting Strategies Training
There is no doubt that killer whales learn from each other. Many of the skills these animals learn and share relate to their roles as advanced predators.
Scientists have described killer whales kill and eat blue whales (Balaenoptera musculus) for the first time in study published last year. In the months and years following the first attack in March 2019, killer whales preyed on blue whale calves and juveniles in two additional incidents, pushing the juvenile blue whales below the surface and suffocating them.
This recently documented hunting behavior is an example of social learning, in which strategies are shared and passed on from adult killer whales to their young. Robert Pitmana marine ecologist at Oregon State University's Marine Mammal Institute, told Live Science in an email. “Whatever the adults learn will be passed on” from the dominant female in the herd to her offspring, he said.
Killing the blue whale “requires cooperation and coordination,” Pitman said. Killer whales may have learned and honed the skills needed to deal with such huge prey. in response to whale population recovery from whaling. This know-how was then passed on until killer whales became highly skilled at hunting even the largest animals on Earth, Pitman said.
Old tricks, new observations
Some of the murderous behavior that researchers have recently observed may actually be long-standing habits.
For example, during blue whale attacks, observers observed that killer whales inserted their heads into the mouths of live whales to feed on their tongues. But this probably isn't new behavior—just a case of people finally taking a closer look at it.
Killer whales are similar to humans in that they have “preferred cuts of meat,” Pitman said. “When hunting large whales, they almost always grab the tongue first, and sometimes that’s all they eat.”
Tongue is not the only delicacy that killer whales seek out. Two males, nicknamed Port and Starboard, have been off the coast of South Africa for several years now. killing sharks to remove their livers.
Orcas are similar to humans in that they have “preferred cuts of meat.”
Although behavior first surprised the researchersIt is unlikely that killer whales have recently started eating liver due to social learning, Michael Weissbehavioral ecologist and director of research at the Center for Whale Research in Washington State, told Live Science.
Connected: Killer whales attacked a great white shark to eat its liver in Australia, crushed carcasses show
That's because this year scientists also caught Footage of killer whales swallowing the liver of a whale shark off the coast of Baja California, Mexico. The likelihood that Port and Starboard transferred their know-how across thousands of miles of ocean is vanishingly small, meaning that liver-eating is likely a widespread and well-established behavior.
“As there are more cameras and boats, we're starting to see behavior that we haven't seen before,” Weiss said.
We share cleaning methods
Orcas learn and share more than just hunting secrets. Several populations around the world have learned to poach fish caught for human consumption from longlines used in commercial fisheries and have passed on this information.
In the southern Indian Ocean, around the Crozet Islands, there are two populations of killer whales. more are being caught on longlines since fishing in the region expanded in the 1990s.. By 2018, the entire population of killer whales in these waters had taught each other to feast on the longline buffet, and entire groups that previously fed on seals and penguins had developed a taste for human-caught toothfish.
Sometimes, killer whales' ability to quickly learn new behaviors can have fatal consequences. In Alaska, killer whales have recently begun feeding on bottom-dwelling fish caught by bottom trawlers, but many end up becoming entangled and killed in fishing gear.
“This behavior may be common across individuals, which may be why we see an increase in some of these deaths“McInnes said.
Playing creepy games
Orcas' impressive cognitive abilities extend to playtime.
Giles and her colleagues are studying endangered population of salmon-eating killer whales off the northern Pacific coast. These killer whales, called the southern resident population, do not eat mammals. But over the past 60 years they developed a unique game in which they search for young porpoises, sometimes with their umbilical cords still attached, and play with them to death.
Connected: “A huge mass of flesh, armed with teeth”: how killer whales gained a reputation as “killers”
According to Giles, there have been 78 recorded cases of these killer whales bouncing porpoises around each other like a ball, but not a single documented case of them eating small mammals. “In some cases you will see teeth marks where [killer] the whale was clearly holding the animal tenderly, but the animal was trying to swim away, so it scratches the skin.”
Researchers believe the games could teach young orcas how to hunt salmon, which are about the same size as baby porpoises. “Sometimes they'll let the porpoise swim away, stop and then go after it,” Giles said.
Are people chasing killer whales to become smarter?
McInnes said humans may be indirectly encouraging orcas to become smarter by changing ocean conditions. Killer whales' forays into longline and trawl fisheries show, for example, that they are inventing and learning new techniques in response to human presence at sea.
Human-caused climate change may also force killer whales to rely more heavily on each other to learn.
In Antarctica, for example, the killer whale population typically preys on Weddell seals (Leptonychotes Veddelii), washing them off the ice floes. But as the ice melts, they adapt their hunting methods to catch leopard seals (Hydrurga leptonyx) and crabeater seals (Lobodon carcinophagus)—two species that don't rely as much on ice floes and are “a little feistier”—require killer whales to develop new skills, McInnes said.
While human behavior can stimulate new learning in orcas, in some cases we also damage the connections that underlie social learning. For example, overfishing of salmon off the coast of Washington has destroyed the social glue that holds killer whale populations together.
“Their social bonds become weaker because you can't be in a large hanging group of killer whales if you're all hungry and trying to find food,” Weiss said. As killer whale groups break up and shrink, so too does the opportunity to learn from each other and adapt to their rapidly changing ecosystem, Weiss said.
And while the killer whales likely don't know that humans are to blame for changes to their ocean habitat, they are “acutely aware that humans are out there,” McInnes said.
Fortunately for us, he added, killer whales don't seem interested in training their deadly skills on us.
