How and why are Orcas (theory) removing Great White Shark livers and other select organs with ‘surgical precision’ near South Africa?
Orca whales have claimed the life of another great white shark by eating its liver and leaving it for dead, making it the fourth such gristly death in less than two months.
During a four-day period in early May, researchers reported finding the bodies of three great white sharks (Carcharodon carcharias) that had washed ashore along South Africa’s Western Cape province. All of these sharks were mysteriously missing their livers, necropsies (animal autopsies) showed.
Now, a fourth dead, liverless shark has washed ashore, according to a post today (June 26) on the Marine Dynamics blog, a site hosted by a shark cage diving company. The newly discovered 13-foot-long (4 meters) male shark was missing its liver, testes and stomach, according to the blog post.
Are killer whales slaughtering great white sharks for their LIVERS? Orcas remove the organs with ‘surgical precision’ in a new spate of attacks
Nature can be so cruel and the dexterity these enormous animals are capable of is mind blowing… almost surgical precision as they remove the squalene-rich liver of the white sharks and dump their carcass.’
A massive shark autopsy effort followed. “It is no easy task to manoeuvre such a huge fish from a remote beach to an adequate site for autopsy,” Towner told Gizmodo. “This required a military vehicle and land rover along with lots of manpower and team work.” The autopsy on the largest shark took six hours and blunted twenty knives, she said. But then another smaller, liverless (and heartless) great white shark carcass washed up on May 4th. And another washed up just yesterday, with matching injuries.
Serial killer (whales) are on the loose! Three dead liver-less sharks washed up on the shores of South Africa’s Western Cape province in a span of four days. One was also missing its heart.
According to a report from Live Science, the bizarre phenomenon prompted scientists to perform necropsies on the three bodies. The animal autopsies revealed that orcas were behind the attacks, although no one actually witnessed the events.
“These observations are unprecedented,” white shark biologist Alison Towner wrote on the Marine Dynamics blog. “We don’t really know how long the sharks will stay away from the area as a result of predation pressure.”
Great white sharks is not the usual prey of killer whales, but it’s not totally unheard of specifically in places like southern Australia and San Francisco.
But why the liver? … Shark livers are particularly appealing because they are filled with fats, energy and nutrients.
“Bony fishes have a swim bladder that they can fill with gases, and those gases provide buoyancy for the fish,” Nosal said. “Sharks do not have a swim bladder. Instead, they have a very large liver.”
With their high metabolism and bloated nutrient needs, orcas could likely benefit from the fat provided by snacking on the livers.
According to Newsweek, an orca has once been observed attacking a great white shark near San Francisco, flipping it upside down before consuming most of the body. One researcher told Newsweek that killer whales are known to learn and spread new hunting tricks, but the distance and time between attacks would make that unusual.
According to the New Zealand Herald, these attacks are not just mystifying, they’re also scaring away sharks from an area of the western coast of South Africa that is normally considered one of the best in the world for seeing sharks, so much so that Gansbaai calls itself the Great White capital of the world. Local shark diving tours, which normally benefit from millions of dollars in tourism, report no sightings of the animals in recent expeditions.
A non-Orca motive might be to examine liver damage from radiation in the wild.