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When a dead great white shark washed up on an Australian beach in October, authorities immediately suspected foul play.
The shark’s belly was torn open, a rare turn for one of the ocean’s most feared predators.
Now scientists have confirmed who killed the giant predator: a killer whale or, more likely, a pod of killer whales.
Cleaning bite wounds has revealed traces of killer whale DNA, Dr. Adam Miller of Deakin University announced this week.
The great white shark washed up on the beach, with its head and spine intact, but its liver missing. Signs pointing to orcas
“We effectively took genetic samples, a swab from the bite wounds,” said Miller, associate professor of aquatic ecology and biodiversity. told ABC Radio Melbourne.
‘We were able to confirm that those bite marks were simply loaded with killer whale DNA. So it is irrefutable proof.”
The shark in question was nearly 16 feet long, Miller said.
That’s relatively large by great white standards, with the largest individuals growing to about 20 feet long and weighing up to about 4,400 pounds.
Great white sharks may be giant, but killer whales are even bigger: They measure 20 to 26 feet long and weigh more than 13,000 pounds.
The mangled remains were found washed up on Bridgewater Bay beach in Victoria, opposite Port Phillip from Melbourne.
The carcass of the great white shark was found in October, washed up on Bridgewater Beach in Victoria, Australia. It was destroyed, but the liver seemed to be the only part that was eaten.
A different large white corpse, seen after the killer whales precisely ripped out its liver.
Bite marks were found on the pectoral girdle, the portion of the belly between the fins on the underside of the shark.
This is also where orcas are known to bite other shark species, including blue sharks and makos.
“They effectively suck out the liver,” Miller said. These things are very picky eaters.
Orcas had been sighted in the area in the days before the attack, including a pair of well-known males named Bent Tip and Ripple, Miller said.
“We can determine individuals” by their distinctive markings, he added.
“They were corralling and releasing what appeared to be a small whale, according to some of the public reports we received, which was interesting,” Miller said.
Because whales were actively hunting in the area shortly before the dead shark was found, observers speculated that mammals might have been to blame, Miller said, “which is something that hasn’t really been documented before in Australian waters.
Scientists and other observers have seen killer whales harassing great white sharks in Australian waters, but have not seen them killing any giant fish.
However, orcas have been recorded hunting and killing great whites and other shark species in California and in large numbers off the coast of South Africa.
In fact, the number of great whites has decreased significantly in South African waters due to increased orca hunting, Miller said.
Earlier this year, a pair of killer whales appeared to have killed a whopping 17 sharks in just 24 hours.
Last year, scientists captured stunning footage of killer whales chasing a great white shark.
We may be familiar with great white sharks as the ocean’s most fearsome predator, but for the first time, this video reveals how they behave when they become prey.
The shark swam in tight circles, trying to evade the larger orcas that were chasing it.
Unfortunately for the shark, this maneuver was not enough to save it from the whales, which hunt in groups.
And scientists suspect that “cultural transmission” may occur between orcas.
In other words, they seem to teach each other how to hunt.
Great white sharks also appear to be learning, as the 2022 report found that surviving sharks abandoned their hunting grounds after killer whales killed others.
“When you remove a top predator, it can actually have a pretty measurable impact on the structure of marine ecosystems,” Miller said.
Superpredators, such as great white sharks, keep their prey populations in check, and when they leave or are killed, the balance of the ecosystem is upset.
“It’s something we just want to monitor because white sharks in Australia are a vulnerable species.”