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scientists have seen orcas Juvenile nursery hunting shark For the first time, turn them over Reverse and feeding on their energy-rich liver, a discovery that suggests changing seasonal diets killer whales,
orcas have previously seen only hunting on adult great White shark In South Africa, one shark provides enough food for an entire pod.
Now, researchers have documented a pod of orcas in the Gulf of California after a special hunting techniques Repeatedly targeting teenage great whites, turning them over, and taking out their livers to share among themselves.
Scientists say in a new study that orcas may be taking advantage of local nurseries of less experienced juvenile sharks, which are easier to capture and tame.
Researchers suspect that these orcas, called “Moctezuma’s pod,” are taking advantage of the warmer waters in the bay, altering shark nursery areas.
Study shows Orcas may be hunting great white sharks More often than previously thought.
“I believe that orcas that eat elasmobranchs – sharks and rays – could, if they wanted, eat a great white shark wherever they go looking for one,” said marine biologist Eric Higuera Rivas, author of the study published in the journal Nature. Frontiers in Marine Science.
“it Behaviour “This is a testament to the advanced intelligence, strategic thinking and sophisticated social learning of orcas, as hunting techniques have been passed down for generations in their pods.”
Researchers described two hunts by orca pods, during which they killed three white sharks.
The first hunt in August 2020 involved five orcas chasing a juvenile white shark.
Researchers observed that the orcas pushed the shark to the surface and worked together to turn it upside down.
The pod carried the shark underwater and resurfaced with its liver in their mouths.
The pod was later found hunting another juvenile shark in the same manner.
In August 2022, researchers found orcas following a similar pattern of pushing a juvenile white shark onto its back and then to the surface. Orcas were observed eating shark liver.
Flipping a shark upside down is believed to cause a condition called tonic immobility, which means paralyzing the shark by altering its awareness of its surroundings.
“This temporary state leaves the shark defenseless, allowing the orcas to extract their nutrient-rich liver and possibly other organs before discarding the rest of the carcass,” Dr. Rivas explained.
The latest findings indicate that orcas may have developed a special technique to induce this state of immobility, which reduces the chance of being bitten by a shark. “Adult white sharks respond immediately to orca predation, completely evacuating their seasonal gathering areas and not returning for months,” said another study author, Salvador Jorgensen, of California State University. “But these juvenile white sharks may be naive to orcas.”
“We don’t yet know whether white sharks’ anti-predator flight responses are innate or need to be learned.”
Researchers also suspect that climate events such as El Niño have altered white shark nursery areas and increased their presence in the Gulf of California. This may expose the sharks to this pod, and each new generation of juveniles may be a vulnerable seasonal target.
“Future studies should continue to monitor the shifting ranges and aggregation sites of juvenile white sharks driven by ocean warming,” the study said.