Orcas in the Gulf of California Are Attacking Great White Sharks

An orca pod that made headlines last year for gutting a whale shark has struck again, this time perfecting a technique that involves paralyzing young great white sharks to eat their livers.

Researchers have spotted the Moctezuma pod in the Gulf of California repeatedly attacking and feasting on the livers of juvenile great white sharks in first-of-their-kind observations.

The orcas temporarily paralyze their prey, according to a new study, by flipping the small sharks upside down, thereby changing their awareness of their surroundings and forcing them into a trance-like state known as tonic immobility.

"This temporary state renders the shark defenseless, allowing the orcas to extract its nutrient-rich liver and likely consume other organs as well, before abandoning the carcass," said study author Jesús Erick Higuera Rivas, a marine biologist and director of the nonprofit research organization Conexiones Terrama.

In 2015, researchers in Gansbaai, South Africa, noted that the population of great white sharks began to drop markedly, but they didn't know why. In 2017, they discovered orcas hunting adult great white sharks, two in particular, that skillfully attacked their undersides to pull out the animal's liver, leaving the corpse, otherwise intact, to wash up on the shore. Their predation was so effective that the great whites relocated elsewhere, effectively destroying the South African shark-watching industry.

However, "this is the first time we are seeing orcas repeatedly target juvenile white sharks," study co-author Salvador Jorgensen, a marine ecologist at California State University, Monterey Bay, said, adding, "Adult white sharks react quickly to hunting orcas, completely evacuating their seasonal gathering areas and not returning for months. But these juvenile white sharks may be naive to orcas. We don't know whether white shark anti-predator flight responses are instinctual or need to be learned."

Two of the three attacks took place in August 2020. Five female orcas from the Moctezuma pod pursued one young great white shark until it tired, pushed it to the surface, and turned it onto its back. They forced the shark underwater, and when they reappeared, they were holding its liver in their mouths. Shortly after this kill, the orcas chased and gutted a second young great white.

The third attack was in August 2022 and followed a similar sequence.

"This behavior is a testament to orcas' advanced intelligence, strategic thinking, and sophisticated social learning, as the hunting techniques are passed down through generations within their pods," Higuera Rivas said.

Great whites only recently started breeding in Mexican waters. Rising ocean temperatures and climate events such as El Niño appear to have shifted the distribution of great white shark nurseries.

You can see a video of how they do it here. www. iflscience.com/watch-orcas-use-tonic-immobility-to-suckan- enormous-liver-out-of-the-worlds-deadliest-shark-81418

This article, by Sascha Pare, was initially published by Live Science.