New orca population found preying on Sperm Whales

California - A new study has revealed that a group of orcas occasionally sighted off the coast of California and Oregon over the last two decades may be a new and unique orca population.

Orcas are rarely seen off the coast of California.
Orcas are rarely seen off the coast of California.  © IMAGO/SuperStock

A new population of orcas discovered in the Pacific Ocean near the coast of California has shocked scientists with unique characteristics and hunting habits that target the world's largest predator.

The discovery comes just weeks after critically endangered Gray Whales were spotted for the first time in 200 years off the coast of Martha's Vineyard.

While that sighting was attributed to the impacts of climate change, a new orca population is a very different discovery.

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Important to the discovery is that the orcas were found in the open ocean, a habitat unusual for the animals. Also unusual, they were found hunting sperm whales and seemed to have been nibbled on by cookiecutter sharks.

New orca population highly unique and unusual

In a peer-reviewed study published in the journal Aquatic Mammals last week, scientists from the University of British Columbia identified a group of 49 orcas that have been hunting sperm whales, dolphins, and elephant seals 200 miles off the Californian coast.

While orcas are found in all oceans, they generally populate colder waters around the poles and are rarely discovered in deep oceans so far from the coast. On top of that, it is highly unusual for them to be hunting large animals like sperm whales.

The orcas have been observed nine times from 1997 to 2021, and while they carry many unusual characteristics, the study's lead author, Josh McInnes, made a point of stressing that they are a subpopulation, not a new species.

"The open ocean is the largest habitat on our planet, and observations of killer whales in the high seas are rare," McInnes explained in a press release. "It is the first time killer whales have been reported to attack sperm whales on the West Coast."

Another curiosity is that the killer whale population has odd scaring not usually seen in any other killer whale population. The small-to-medium-sized circular marks indicate cookie-cutter shark bites.

"A key clue to the new population's presumed habitat range lies in cookie-cutter shark bite scars observed on almost all the orcas... This parasitic shark lives in the open ocean, meaning the new population primarily inhabit deep waters far from land."

Impressively, the group of orcas managed to take on a herd of nine adult female sperm whales, killing and feeding on one of them. It is the first time that such a thing has been observed, and extraordinary considering the size and nature of sperm whales.

"They were observed taking on a herd of nine adult female sperm whales, eventually making off with one," McInnes said. "It is the first time killer whales have been reported to attack sperm whales on the West Coast."

Cover photo: IMAGO/SuperStock

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