Were polar bears feasting on fish in Scotland 30,000 years ago?

Thousands of years ago, a roar echoed through the Highland caves of Scotland. It was the roar of bears. But, were these the average brown bears or something more “polar” in nature?

Using advanced methods to analyze Scottish bear fossils, researchers from the University of Aberdeen and National Museums Scotland have made a fascinating discovery.

Analyzing the bear fossils

The study was led by Professor Kate Britton, an expert known for her insightful approach to ancient fauna.

The experts reevaluated fossils collected from the Inchnadamph “Bone Caves” in Sutherland. What they found was evidence of fish in the diet of bears that had been identified as brown bears.

Working closely with masters student Holland Taekema from the University of Edinburgh, the team used a technique known as “stable isotope data” to dig deeper into the diets of the fossilized bears.

The evidence they unearthed pointed to a marine diet dating back to 30,000 to 50,000 years ago. This means that the bears were feasting heavily on seafood long before human footprints graced Scottish lands.

Could the fossils belong to polar bears?

As exciting as it sounds, this revelation required a fair bit of head-scratching. After all, it’s a hard shift from the grisly diet of modern brown bears.

The research suggests an intriguing possibility – could these have been polar bears frolicking in Scottish terrain amidst the Last Ice Age?

“We have identified several samples which stick out like a sore thumb both from the diets of other bears living in Scotland thousands of years ago and from what we’d expect of today’s brown bears. These bears appear to have lived almost exclusively on seafood,” said Professor Britton.

A polar perspective

Indeed, the frosty north is the only homeland we associate with polar bears today, but our researchers remind us that the Last Glacial Maximum brought down the seasonal sea ice limit in the North Atlantic, allowing these majestic creatures to roam further south than their current territories.

A similar theory was hinted at in the 1990s, revolving around a bear skull with polar bear-like features. However, lack of further evidence and questions about the skull’s radiocarbon dating have put a pause on accepting this interesting possibility.

Dr. Andrew Kitchener is the Principal Curator of Vertebrates at National Museums Scotland.

“As we know that polar bears and brown bears can successfully interbreed today where their ranges overlap, it presents interesting questions about the ancestry of bears that later roamed our islands,” noted Dr. Kitchener.

The Ice Age connection

To shed light on the intriguing genetic links between modern polar bears and Ice Age European brown bears, the research team is embarking on an ambitious journey.

By analyzing the DNA of brown bears from different regions and comparing it to the genetic makeup of present-day polar bears, they aim to uncover the ancestral ties that bind these species together.

This comprehensive genetic analysis, coupled with the isotopic evidence from the bone caves, may hold the key to unraveling the mysteries surrounding the enigmatic fossil bears.

Preserving the past

The bears fossils, now meticulously curated by the experts at National Museums Scotland, will continue to serve as invaluable resources for ongoing research.

The team plans to go deeper into the fossil record, exploring additional bone caves and collecting further samples for analysis.

By employing state-of-the-art techniques and collaborating with multidisciplinary experts, they hope to unlock new insights and unveil more secrets about the ancient bears that once roamed our lands.

Future research directions

The plot only thickens as the team sets out to further explore the mystery.

The researchers plan to unearth the connections between brown bear DNA in modern polar bears and polar bear DNA in Ice Age European brown bears.

The challenge is to understand how this genetic data links to the isotopic evidence from the bone caves.

The fossil bears will be the subject of ongoing research by a newly-appointed research fellow, Dr. Alicia Sanz Royo, at the University of Aberdeen in 2025.

The study is published in the journal Annales Zoologici Fennici.

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