Video Catches Orca Pod Chasing a Great White Shark Near Seal Island

Great white sharks (Carcharodon carcharias) have earned a formidable reputation but while they may be apex predators and can claim to be the world's largest known predatory fish, they do have one powerful adversary—orcas, or killer whales (Orcinus orca).

Orcas were dubbed killer whales (or, in Spanish, asesina ballenas) after ancient sightings of the animals ganging up on, and killing, other (frequently larger) whale species. Their scientific name "Orcinus" literally translates to "belonging to Orcus," Orcus being a Roman god of the underworld. More recently, orcas have also been known to attack and kill great white sharks.

New footage captured at Seal Island in Mossel Bay, South Africa, on November 7, 2019, shows a group of orcas hounding a great white. The video was taken by Oceans Research, a marine research, education and conservation organization based in South Africa, which posted the clip on its Facebook page last week.

"Orcas were spotted chasing a white shark, and a few other white sharks were in the vicinity at the time," Oceans Research wrote in a Facebook post.

"One white shark appears to be unnerved by the presence of the orcas, but another shark didn't seem too perturbed."

One reason for these attacks is a penchant for shark liver. Biologists also believe orcas might choose to pursue great whites near hunting grounds to drive away competition and leave more prey for themselves.

The first documented incident of orcas attacking a great white shark happened as recently as October 1997, when two cetaceans were caught pursuing a shark before eating its liver near the Farallon Islands, off the coast of San Francisco, by tourists in a whale watching boat.

More recently, conservationists working in South Africa have noticed an increasing number of orca-on-shark attacks taking place there. This follows a rise in orca observations in the area since 2009.

When five great white sharks were found washed up in Gansbaai, South Africa, with suspicious-looking wounds in 2017, orcas were the suspected culprits.

"There were distinct bite marks on the pectoral fins of the dead sharks. These evenly spaced, circular tooth impressions were identified as most likely being from a "flat-toothed" killer whale, which is rare in coastal waters," biologists Alison Kock and Tamlyn Engelbrecht wrote in an article for Newsweek.

"There were no bites anywhere else on the body, indicating that the killer whale (or whales) had likely pulled on the pectoral fins to open up the body cavity, to remove the liver. The sharks' liver accounts for up to a third of its weight and is rich in fat, a nutrient that killer whales seek out."

Studies suggest great white sharks are so fearful of orcas that they will desert their preferred feeding grounds if there is an orca sighting or attack—and sometimes will not return for a year.

Oceans Research says they will monitor any orca and white shark activity over the coming days to determine whether or not the incident has caused any behavior changes.

great white shark
Great white sharks have one powerful adversary—orcas. Orcas have been known to kill white sharks for their liver. Whitepointer/iStock