RYAZANOV S.D., FOMIN S.V., ATOPKIN D.M., ELISEIKINA M.G.
Океанология 2026; 66(2): 368-379
There are three ecotypes of killer whales divided in the North Pacific Ocean: R-type, T-type and offshore. It is believed that the basis of the diet of T-type killer whales, currently considered as a separate subspecies (or species), are marine mammals, but there is not much data on the content of the gastrointestinal tract (GIT) of these animals. The Commander Islands inhabited by a local population of Steller sea lions, which is declining for unknown reasons. In 2021, a T-type killer whale carcass was found in the archipelago, and the first report of a killer whale eating a Steller sea lion off the Commander Islands was published. We performed a detailed analysis of the GIT of this killer whale. The GIT contained the fur of a true seal (Phocidae), most likely the bearded seal, but not a Steller sea lion, and the beaks of a large squid species of the family Ommastrephidae. The estimated total weight of the squids swallowed by the killer whale reaches tens of kilograms. The obtained data clarify and supplement the known information about the diet of T-type killer whales and show that in addition to marine mammals, squids make up a significant part of their diet.
