Corkscrew Wounds on Baby Seals: The Real Killer Has Been Caught

Sable Island is a 26-mile sliver of sand off the coast of Nova Scotia, and every winter it becomes the birthplace of roughly 80,000 gray seal pups. It has also, for nearly four decades, been the site of something nobody could explain: pups turning up dead with spiral wounds running from mouth to chest, the skin and blubber stripped off like a jacket. Scientists named them corkscrew wounds. They suspected Greenland sharks. They suspected boat propellers. Neither theory produced a single observed incident, and eventually the question just sat there, unresolved, while the bodies kept accumulating each season.

In January 2024, a researcher from the University of St. Andrews named Izzy Langley arrived at the island to study how seals track cod. What she documented instead was a large adult male gray seal approach a freshly weaned pup, bite it near the face, and slowly rotate his body, peeling away the skin and fat layer in a continuous spiral. The pup sat still the entire time. It had grown up surrounded by large seals and had no instinct telling it to be afraid of them.

Here's why the males do it: breeding season males don't eat for weeks, burning through fat reserves while guarding territory. The pups, meanwhile, are around 50% body fat after weeks on their mothers' milk, and they don't move much. A subset of males appear to have independently discovered the pups as a food source. In 2023, a single month of beach surveys turned up 765 corkscrew-wound carcasses on 20 kilometers of coastline. In 2024, one day produced 359.

The paper also suggests that the collapse of harbor seals at Sable Island, previously attributed to Greenland sharks, may warrant a fresh look.

Read the full story at Marine Mammal Science, February 4, 2026

Hot Take: The sharks have an alibi. The propellers have an alibi. The baby seals and their mothers now know the call was coming from inside the colony.