Dans une étude publiée vendredi, des chercheurs déclarent qu'un groupe de 49 orques avait été observé en train de chasser des cachalots au large des côtes américaines de la Californie et de l'Oregon.

In a study published Friday, researchers said a pod of 49 killer whales had been observed hunting sperm whales off the U.S. coasts of California and Oregon.

Lead author Josh McInnes wrote in a statement that in one case, killer whales were seen chasing a herd of nine adult sperm whales, “only to leave with one.”

Mr McInnes said this would be the first time killer whales have attacked sperm whales on the west coast.

The master’s student at the University of British Columbia’s Institute of Oceans and Fisheries says other “encounters” with killer whales include an attack on a pygmy sperm whale and predations on a boreal elephant seal and on a Risso’s dolphin.

Researchers say the killer whales seen in nine encounters between 1997 and 2021 could belong to a subpopulation of coastal killer whales, or to a unique ocean population.

The article says researchers have been able to identify the killer whales as perhaps a new group, in part because of bite scars on their bodies caused by the ferocious squalelet, a small parasitic shark that lives in the depths of the ocean.

Mr McInnes points out that almost all orcas had scars, while others had no scars. “But the big question is where do these orcas fit (in the classification)? We don’t know (…), but what we do know is that they represent a population that seems to be spending more time on the high seas,” Mr McInnes said in an interview.

Study co-author Andrew Trites of UBC’s Institute of Oceans and Fisheries said it was “quite unusual” to find a new population of killer whales, given the time it took to take photos and identify animals. recognize as different from already known populations.

The researchers said they also observed physical differences in the orcas, such as spots on their fins and backs.

They now hope to document more observations and data on the new population to study exactly how different these killer whales are from other known populations.

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