"I've been thinking about this possibility for 15 years": Killer whale experts make new discovery off North American coa

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“I've been thinking about this possibility for 15 years": Killer whale experts make new discovery off North American coast
New research has revealed that West Coast transient killer whales – found from south-eastern Alaska to southern California – are two distinct communities that rarely encounter each other.



Daniel Graham
Published: November 10, 2025 at 3:55 am


West Coast transient killer whales have long fascinated marine scientists with their impressive mammal-hunting techniques. Now, new research by the University of British Columbia (UBC) is shedding more light on these large ocean predators, confirming them to be two distinct subpopulations: inner and outer coast transients.

Analysing 16 years of data covering more than 2,200 killer whale encounters, the study, published in PLOS One, reveals that these two groups are split along an east–west divide and rarely mix.

“I've been thinking about this possibility for 15 years,” says first author of the study Josh McInnes from UBC’s Institute for the Oceans and Fisheries (IOF).

“Now our findings show the West Coast transients are two distinct groups. They eat different things, hunt in different areas and very rarely spend time with each other.”

West Coast transient killer whales are one of six populations of transient killer whales worldwide. Found from south-eastern Alaska to southern California, the group was previously thought to be split in a north-south divide, but the new research confirms a distinct east–west (or inner–outer) divide. ...................(more)

https://www.discoverwildlife.com/animal-facts/marine-animals/west-coast-transient-killer-whale-subpopulations