Shark teeth found in 5-million-year-old whale skulls provide direct evidence of ancient feeding behavior and predator-prey relationships in the North Sea.
Researchers studying two fossilized whale skulls discovered pieces of shark teeth lodged inside the bones, providing rare physical evidence of prehistoric feeding behavior in northern European waters.
The research, led by the Royal Belgian Institute of Natural Sciences (RBINS), used detailed CT scans to examine the skulls. These scans revealed broken shark teeth that became embedded in the whales’ skulls during feeding, allowing scientists to better understand how these predators interacted with their prey.
Dr. Olivier Lambert, a paleontologist at the Institute of Natural Sciences who examined the fossils, said, “Our knowledge of past marine mammal assemblages in the North Sea remains rather fragmentary, so any new fossil may prove informative. In this case, the studied skulls revealed some unexpected and fascinating clues about the way these whales’ lives ended.”
CT Scans and Fossil Discoveries in Belgium
The skulls date back to the Early Pliocene period, about 4–5 million years ago, and were both found in Belgium. One skull, belonging to a small extinct right whale species, was discovered in the 1980s by Professor John Stewart, an evolutionary paleoecologist at Bournemouth University, while fossil hunting with his father in the Antwerp docks.
The second skull comes from a monodontid, a relative of today’s beluga and narwhal, and was found by fossil enthusiast Dr. Paul Gigase, a pathologist, along with his son Pierre.
Decades after the first discovery, modern imaging technology has revealed new details hidden inside the fossils. Dr. Lambert, lead author of the study, said, “The CT scans revealed the shape of the teeth, allowing the sharks’ identification without having to damage the skulls. The position of the bite marks in the upper part of the right whale skull tells us that the animal had probably already died when the shark scavenged its carcasses and that it was in a belly-up position, which is common for deceased whales.”
One of the tooth fragments, found in Professor Stewart’s specimen, came from a cow shark. The other belonged to a species related to the modern great white shark. Neither of these sharks, nor their close relatives, inhabit the southern North Sea today.
Prehistoric Predator-Prey Dynamics in the North Sea
Together, these fossils provide a rare look at interactions between large marine predators and whales off the coast of Northern Europe millions of years ago.
Professor Stewart said, “Paleontologists often have to make assumptions about the interactions between many of the species from this period. This study provides them with actual evidence they can work with—not just bite marks, but fragments from the predators who made the bites.”
Today, the idea of whales and large predatory sharks sharing the same waters in Northern Europe may seem unusual. However, fossil evidence is helping scientists reconstruct a time when these species coexisted in the region.
Dr. Lambert said, “These whale skulls provide a rare glimpse into the relationship between large predators and their prey off the coast of Northern Europe 5 million years ago. These findings are a first step towards understanding changes through time in the availability of prey in the southern North Sea and the loss of large predatory sharks in this area. Given that ongoing climate change is altering the distribution of marine mammals, including in the North Sea, it is likely that the distribution of their predators will also change. Could great white sharks return to the North Sea to feed on local seal populations?”
Reference: “Evidence for different shark species feeding on a diminutive right whale and a relative of the beluga in the Early Pliocene of the southern North Sea” by Olivier Lambert, John R. Stewart, Stephen Louwye, Luc De Coninck, Mark Bosselaers, Lucile Crété, Stijn Goolaerts, Christophe Mallet and Frederik H. Mollen, 18 March 2026, Acta Palaeontologica Polonica.
DOI:10.4202/app.01297.2025
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