All killer whales are currently categorized as a single species, but a new study may change that. Researchers suggest in the journal Royal Society Open Science that two populations of killer whales, resident and Bigg’s killer whales, should be recognized as separate species, distinct from both each other and the rest of killer whales.
The study, which reviewed previous research and conducted new analyses, looked at a number of characteristics of the two populations, including their social structures, diets, shapes, sizes and DNA.
“These two types are genetically two of the most distantly related types in the whole world,” Phillip Morin, a co-author of the study and geneticist at the Southwest Fisheries Science Center at the National Oceanic and Atmospheric Administration (NOAA), tells the New York Times’ Emily Anthes. “They’re not just behaving differently. They really are on these evolutionary trajectories which we consider to be different species.”
John Ford, a killer whale researcher at Fisheries & Oceans Canada who did not contribute to the findings, tells Hakai Magazine’s Craig Welch that the paper is thorough and definitive. “There’re just pieces of the story that have fit together to build, I think, a compelling case,” he says to the publication.
Killer whales (Orcinus orca) are apex predators that are found in oceans all around the world. Different groups live in diverse climates, make a variety of sounds and have a wide range of diets. A number of previous studies have argued that O. orca is actually made up of more than one species.
Researchers going back to at least 1970 have noticed differences in behaviors in different groups of killer whales, per Hakai Magazine. Today, scientists recognize multiple types of killer whales, called “ecotypes,” according to the new study.
