Ancient North Sea Predators Hint at Climate-Driven Return of Great White Relatives

Original publisher: The Conversation. A new palaeoecological study of two Early Pliocene cetacean skulls from the southern North Sea, preserved with shark tooth fragments, provides direct fossil evidence that relatives of today’s sharks fed on whales in this region when climates were warmer. The findings illuminate how ancient ecosystems reorganized in response to climate shifts and offer a warning about how current warming may reshape marine predator–prey relationships in modern North Sea waters between the UK, Belgium and Denmark.

• Two cetacean skulls with embedded shark teeth reveal direct predation by shark relatives in the Early Pliocene North Sea.
• Turnover in cetacean communities during the Pliocene–Pleistocene likely influenced the disappearance of large sharks from the North Sea.
• Contemporary warming could recreate conditions that attracted large predators to this shallow seascape again, with potential shifts in the distribution of porpoises, seals, and great-white shark relatives.
• The fossil record helps interpret today’s biodiversity crises by linking past climate-driven ecological changes to present-day marine ecosystems.

Introduction

The article discusses how the Earth’s shift toward climates not seen for hundreds of thousands of years may force us to consult ancient environments for clues about future ecological responses. A recent palaeoecology study examines two whalebone-bearing cetacean fossils from the North Sea that preserve fragments of shark teeth, providing direct evidence of sharks preying on whales in the Early Pliocene southern North Sea era. The research uses these fossil clues to infer past ecosystem dynamics and to inform our understanding of how modern marine communities might respond to current climate change.

Ancient North Sea Seascape

During the Pliocene to early Pleistocene epochs, the southern North Sea hosted a diverse assemblage of large marine vertebrates, including bluntnose sixgill sharks and relatives of the modern great white shark, Greenland sharks, small baleen whales, beluga relatives, and early dolphins. In contrast to today’s relatively low cetacean diversity in the area, this ancient seascape was a vibrant hub of predator–prey interactions that likely shaped community structure and energy flow in ways that differ markedly from the present day.

Fossil Evidence of Shark Predation

The study highlights direct evidence of past shark–whale interactions: two cetacean skulls bear shark bite marks, with embedded tooth fragments from bluntnose sixgill sharks and relatives of great white sharks. Such fossilised traces are relatively rare and offer tangible confirmation that ancient sharks fed on large whales in this region. While the sample consists of just two pairings, they document a predator–prey relationship that links behaviour to ecological context across deep time.

Pliocene–Pleistocene Turnover and Shark Biogeography

The fossil record indicates a large-scale turnover of cetacean species in the southern North Sea during the ice-age interval bridging the Pliocene and Pleistocene. The extinctions of many small baleen whales and the departure of cetacean families such as belugas may have altered the food web. With the decline of certain whale populations, large sharks (including relatives of the great white) would have faced different prey dynamics, potentially contributing to their disappearance from the North Sea over time.

Implications for Modern Climate Change

The ongoing biodiversity crisis is closely tied to climate change, and warming seas are expected to affect shallow marine environments most strongly. While modern baleen whales are larger and prefer deeper North Atlantic waters, warming conditions could attract smaller cetaceans, dolphins, and seals to the southern North Sea, thereby increasing opportunities for large predators to exploit these habitats. Contemporary observations include short-term shifts in the distributions of porpoises and seals along the southern North Sea coasts, along with rising numbers of stranded porpoises on Belgian beaches, suggesting dynamic biogeographic reorganisations in response to climate variability and ecosystems stressors.

Conclusion

The fossil record, including evidence of shark bite marks on extinct whales, underscores that the North Sea’s ecological community has long experienced climate-driven turnover. As today’s climate continues to warm, the region may once again resemble certain ancient configurations where large marine predators roamed the area. The study emphasizes that understanding past responses to climate change can illuminate present and future trajectories for marine biodiversity and conservation strategies in a rapidly changing ocean.