Emily Chan
In the eastern North Pacific, there are two populations of orcas with qualities that make them stand out from others.
These differences may be enough to justify classifying them as separate species, according to a study published in Royal Society Open Science.
Currently, all killer whales are regarded as a single species. They live in oceans around the world. Different groups are found in diverse climates, have varying diets, and make a range of sounds.
The new study looks at the traits of two populations of orcas—resident and Bigg’s killer whales. Bigg’s are also known as transient killer whales.
“These two types are genetically two of the most distantly related types in the whole world,” Phillip Morin, a geneticist with the Southwest Fisheries Science Center at the National Oceanic and Atmospheric Administration (NOAA) and co-author of the study, said.
“They’re not just behaving differently. They really are on these evolutionary trajectories which we consider to be different species.”
Resident and transient killer whales inhabit the waters of the eastern North Pacific. Residents feed on fish and live near the shore, while transients eat marine mammals and swim farther out in the ocean.
Additionally, residents tend to gather in large, stable communities. On the other hand, transients form smaller groups of orcas that are maternally related and hunt silently with each other.
Residents hunt in larger groups using echolocation, producing sonar clicks more often than transients.
Sign up for Chip Chick’s newsletter and get stories like this delivered to your inbox.
