Orcas Are Killing Great White Sharks And Eating Their Livers

Three great white shark, likely killed by orcas, have washed ashore in South Africa in the past week. SharkwatchSA.com

Great white sharks, one of the most feared animals on the planet, are not without their own predators. In the past week, three great white sharks have been killed by orcas off the coast of South Africa and had their livers removed, researchers have concluded. Prior to this shocking finding, there were no records of killer whales going after great white sharks in this region, though it has been documented elsewhere in a few rare incidents. Orcas are one of the most versatile and fearsome predators in the world, known to eat various types of sharks, seals and whales. But they usually avoid great whites.

Since May 3, all three great white carcasses have washed ashore in the region of Kleinbaai, a small harbour town in the Western Cape of South Africa. In the prior five years, only four sharks had been found on the beaches in this region, considered one of the best places in the world to dive with and see great whites, according to a blog post by Marine Dynamics, a shark cage diving company.

A team of scientists from the area dissected all three of the sharks, and concluded that orcas were responsible for killing the great whites and removing their livers. (One also had its heart removed, likely by a hungry killer whale.) This organ has a high level of squalene, a hydrocarbon that's an important for producing steroids and hormones.

"Obviously this is a very sad time for us all, 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," writes Alison Towner, a white shark biologist for the Dyer Island Conservation Trust who led the dissections, in the Marine Dynamics blog.

The orcas removed the great white's liver, and not much else. SharkwatchSA.com

Orcas are very smart, and have different behaviors for hunting different animals around the world. It is possible that the creatures have now learned to go after killer whales. In 1997, whale watchers off the coast of San Francisco, near the Farallon Islands, filmed a killer whale attacking a great white, after flipping it over.

When turned upside down, many sharks become nearly comatose, and thus easy prey. Samuel Gruber, a researcher at the Bimini Biological Field Station in the Bahamas, said orcas could develop and spread new such hunting tricks. "Their learning abilities are so great, that if one of them happened to" flip over and stun a shark, "and see that [sharks freeze up] in this state, they could communicate it to the other ones," Gruber says in a National Geographic film.