Scientists have uncovered possible evidence that some killer whales may hunt and consume members of their own species in waters near Russia, according to a recent study.
The finding emerged after two severed killer whale fins were discovered on a remote Russian island. According to a recent study, both fins carried clear tooth marks from other killer whales, raising concerns that some orcas may be attacking members of their own species.
Olga Filatova, an associate professor at the University of Southern Denmark, said she first saw photographs of the fins sent by her long-time collaborator Sergey Fomin. She said the discovery came as a surprise.
“When he found the first one, it was very surprising,” Filatova told BBC Science Focus, adding that scientists never expected to witness such behaviour in their lifetime.
Genetic analysis showed that the fins belonged to resident killer whales, a population that primarily feeds on fish and lives in tightly knit family groups spanning several generations.
Researchers suspect the attackers were transient killer whales, another group inhabiting the same waters but known for hunting marine mammals such as seals, sea lions and even other whales.
From a scientific perspective, the incident may be classified as cannibalism because all killer whales belong to a single species, Orcinus orca.
However, Filatova explained that resident and transient killer whales rarely interact, do not interbreed and may not even recognise one another as the same kind of animal.
Scientists believe the attacks could have taken place during large gatherings when multiple resident whale families come together for breeding. During such events, young whales can become separated from their family groups, leaving them more vulnerable to mammal-hunting orcas.
Both fins recovered from the island belonged to young whales. Researchers also pointed out that predators often remove fins during an attack to access the flesh beneath.
Although the conclusions are based on only two fins, scientists say the evidence may help explain why resident killer whales maintain strong family bonds, possibly as a defence against predators from other killer whale groups.
