Researchers have noticed that killer whales in the Gulf of California have repeatedly attacked and eaten the livers of young individuals. great white sharks in first-of-its-kind observations.
killer whales (Orcinus killer whale) used a wild but cunning method to temporarily paralyze their prey, according to a new study. The technique involved turning small sharks upside down, thereby changing their perception of the environment and forcing them into a trance-like state known as tonic immobility.
“This temporary state leaves the shark defenseless, allowing killer whales to remove its nutrient-rich liver and likely consume other organs before abandoning the rest of the carcass,” says the study's lead author. Jesus Eric Higuera RivasThis is stated in a statement by the marine biologist and director of the non-profit research organization Conexiones Terramar.
On three separate occasions, killer whales were observed sharing a shark's liver. The attacks were carried out off the coast of Mexico by the Moctezuma pod, a group of killer whales named after the large male that made headlines last year. brutal killing of a whale shark (Rincodon type).
It was already known that killer whales hunt great white sharks (Carcharodon carcharias) in some regions, including South Africa And Australiabut records of such behavior in the northeastern Pacific are extremely rare, the last reliable sighting being observed off the west coast. documented in 1997. According to the study, sightings in South Africa and Australia mostly involved adult great whites, whose larger proportions and organs mean more food for the orcas.
There's only one previous report orcas that killed a juvenile great white shark. The attack took place in 2023 off the coast of South Africa by a notorious killer whale named Starboard; According to the report, the predator grabbed the juvenile great white shark's pectoral fin and thrust it forward several times before gutting the shark.
The new observations were published Monday (November 3) in the journal. Frontiers of Marine Scienceshow that killer whale attacks on young great whites are more common than scientists thought.
“This is the first time we have seen orcas repeatedly attack juvenile white sharks,” study co-author. Salvador Jorgensenthe marine ecologist at California State University, Monterey Bay, said in a statement. “Adult white sharks respond quickly to killer whale predation. completely evacuating seasonal gathering places and did not return for months. But these young white sharks may be naive about killer whales. We just don't know yet whether white sharks' anti-predator responses are instinctive or whether they need to be learned.”
According to the study, two of the three attacks occurred in August 2020. Five female killer whales from Moctezuma's pod chased one young great white shark until it tired, pushed it to the surface and flipped it onto its back. The orcas eventually forced the shark underwater, and when they reappeared, they were holding its liver in their mouths, the researchers said. Shortly after this kill, the killer whales chased and gutted a second young great white for several seconds.
The third attack occurred in August 2022 and followed a similar sequence. Five killer whales, including one adult male, flipped the young beluga whale like a pancake, pushing her to the surface and biting her to death. Blood gushed from the shark's gills, and its liver protruded from its abdomen just enough for the killer whales to grab it.
A closer look at where the sharks' injuries were found revealed that tonic immobility may minimize the killer whales' chances of being bitten when the orcas attempt to remove the liver. Selecting juvenile prey also limits risk to killer whales, but it is unclear whether killer whales in the Gulf of California only kill juveniles or whether they regularly attack adult great whites as well.
“This behavior is evidence advanced intelligence of killer whalesstrategic thinking and complex social learningsince hunting methods passed down from generation to generation in their capsules,” Higuera Rivas said.
One reason this behavior has been seen now may be that great whites have only recently begun breeding in Mexican waters. Rising ocean temperatures and climate events such as Child This appears to have altered the distribution of great white shark nurseries, and Moctezuma's school likely took advantage of the increased number of juveniles in the Gulf of California.
Other pods of killer whales in the area may become established, study co-author Francesca Pancaldithe marine biologist from the National Polytechnic Institute of Mexico said in a statement. “So far we have only observed this capsule feeding on elasmobranchs. [sharks and rays]”, she said. “It could have been more.”
