Overview
- Two torn dorsal fins with killer-whale tooth marks were recovered on Bering Island in 2022 and 2024 roughly two kilometers apart.
- Genetic analysis identified the remains as resident, fish-eating orcas that are socially and reproductively segregated from mammal-eating transients.
- Authors conclude transient (Bigg’s) orcas most likely predated the residents, while noting that scavenging cannot be ruled out because definitive proof is lacking.
- Dead killer whales typically sink quickly, making scavenging less likely, and the fins’ condition fits a pattern in which predators discard low-energy parts; one discovery followed a large resident gathering that can increase risk.
- Published in Marine Mammal Science, the study presents these incidents as rare and explores how predation pressure and long-term ecotype divergence could underlie residents’ tight matrilineal structure, with outside experts urging caution on broader conclusions.