Scientists have discovered a 75,000-year-old ecosystem preserved in a Norwegian cave, revealing a lost Arctic world of surprising biodiversity. The findings, published in the Proceedings of the National Academy of Sciences, detail a coastal community of 46 different animal species that thrived during a brief, warmer period of the last ice age. This ancient snapshot, unearthed from the Arne Qvamgrotta cave, is the oldest faunal assemblage ever discovered in the European Arctic and provides critical insights into how life responds to major climate shifts. Researchers believe these insights are directly relevant to understanding the challenges that cold-adapted species face from climate change today.

The discovery fills a significant void in the fossil record, as organic remains older than 10,000 years are exceptionally rare in previously glaciated regions. Using techniques such as ancient DNA analysis and radiocarbon dating, the team identified a mix of marine and terrestrial life, including polar bears, walruses, Atlantic puffins, and migratory reindeer. The collection also contained a significant first: the remains of collared lemmings, a species now extinct in Europe that had never been found in Scandinavia before. These fossils date to a time known as Marine Isotope Stage 5a, a warmer “interstadial” when glaciers had temporarily retreated from the coast.

The variety of animals allowed scientists to reconstruct the ancient environment with remarkable detail. The presence of species that require sea ice, such as bowhead whales and walruses, alongside those that avoid it, like harbor porpoises, suggests that the ice was seasonal. The discovery of freshwater fish suggests the presence of unfrozen lakes and rivers on the nearby tundra. “The cave has now revealed a diverse mix of animals in a coastal ecosystem representing both the marine and the terrestrial environment,” said senior author Professor Sanne Boessenkool of the University of Oslo in a Bournemouth University press release.

This once-thriving community ultimately serves as a stark warning. DNA analysis revealed that these specific animal lineages did not survive when colder conditions and massive ice sheets returned. “This highlights how cold-adapted species struggle to adapt to major climatic events,” said lead author Dr. Sam Walker. The study suggests that as the ice advanced, these populations were unable to migrate to suitable habitats and died out locally. Professor Boessenkool noted that if these species struggled to cope with a shift to colder conditions, they would likely find it even harder to adapt to today’s rapidly warming climate.

References

• Bournemouth University. (2025, August 4). Scientists uncover 75,000-year-old Arctic animal remains in Norwegian cave. Phys.Org; Bournemouth University. https://phys.org/news/2025-08-scientists-uncover-year-arctic-animal.html

• Walker, S. J., Boilard, A., Henriksen, M., Lord, E., Robu, M., Buylaert, J.-P., Beijersbergen, L. M. T., Halvorsen, L. S., Cintrón-Santiago, A. M., Onshuus, E. K., Cockerill, C. A., Ujvari, G., Palcsu, L., Temovski, M., Maccali, J., Linge, H., Olsen, J., Aksnes, S., Bertheussen, A., … Boessenkool, S. (2025). A 75,000-y-old Scandinavian Arctic cave deposit reveals past faunal diversity and paleoenvironment. Proceedings of the National Academy of Sciences, 122(32), e2415008122. https://doi.org/10.1073/pnas.2415008122