Transient Killer Whale Facts
Transient killer whales (Orcinus orca), also known as Bigg’s killer whales, are unlike the Southern Residents, exclusively eating marine mammals, including harbor seals, harbor porpoises, and Steller sea lions. They can be found from southern Alaska to central California, but despite their name implying frequent movement, they often call the Salish Sea home.
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The vocal behavior of Transient killer whales is significantly different from that of Southern Resident killer whales. While fish-eating Southern Residents call to one another during foraging, Transient killer whales remain silent in order to successfully surprise and catch their marine mammal prey. Once they catch their prey, they vocalize more readily with one another.
Transient killer whales use a wide range of habitats and some pods spend a significant amount of time in shallow waters less than 5 meters deep, hunting for food in intertidal waters during high tide. One group of transients in the Salish Sea called the T065A matrilineal group, have been recorded intentionally stranding to scare seals they are hunting into the water.
Transient and Southern Resident killer whales avoid one another. The two different ecotypes do not interact, do not interbreed and are genetically distinct. From 2011 to 2017, there was a steady increase in the number of Transient killer whales coming to the Salish Sea. At the same time, likely due to salmon declines, there was a decrease in the number of Southern Residents in the region.
Breaching transient killer whale by Ken Rea. Banner photo by Arial Brewer.