Male Gray Seals Killed 765 Sable Island Pups, Solving 40-Year Death Mystery

3 articles · Updated · Livescience.com · May 22

Researchers directly observed an adult male gray seal attacking a pup on Sable Island in 2024, tying the colony’s long-mysterious corkscrew wounds to cannibalism rather than sharks or ship propellers.
Reanalysis of 2023 drone footage and fieldwork through 2025 found adult males feeding on pups, with bite and claw marks matching the spiral lacerations seen across the island.
The team counted 765 pups with corkscrew injuries during the 2024 breeding season and 359 deaths from those wounds on a single day in 2025, though improved searches may explain part of the jump.
Fisheries and Oceans Canada estimates fewer than 1,000 such deaths among roughly 75,000 gray seal pups on Sable Island, suggesting little effect on the overall gray seal population.
The finding still matters for conservation because harbor seal pups on Sable Island are scarce and declining, and researchers say male gray seals may also prey on them; the cause of the cannibalism remains unknown.

What is driving Sable Island's massive male seals to cannibalize their own young?

A seal mystery is solved, but does this discovery spell doom for another vulnerable island species?