Hippopotamus Survival in Ice Age Europe

Until recently, scientists believed that the common hippopotamus (Hippopotamus amphibius) disappeared from Central Europe around 115,000 years ago, at the end of the last interglacial period. However, a new study by researchers from the University of Potsdam and other institutions has shown that hippos continued to exist in the Upper Rhine Graben region of southwest Germany for tens of thousands of years after that, up until the mid-last glacial period.

Rewriting Extinction History

The Upper Rhine Graben is an important record of ancient climatic conditions. Animal bones buried for thousands of years in layers of gravel and sand provide rare windows into the past. Dr. Ronny Friedrich, an expert in age determination at the Curt-Engelhorn-Center for Archaeometry, commented on the well-preserved condition of the bones, noting that suitable samples for analysis were obtainable from many skeletal remains, which is not guaranteed after such a long time.

Genetic and Radiocarbon Evidence

Researchers examined several hippopotamus fossils using genetic and radiocarbon dating methods. Ancient DNA sequences showed that Ice Age hippos were closely related to modern African populations and were part of the same species. Radiocarbon dating confirmed their presence during a warmer phase of the Middle Weichselian glaciation, when conditions temporarily allowed animals to survive in Central Europe.

Broader genetic analysis revealed that the European hippo populations had extremely low genetic diversity, indicating they were small and geographically isolated. Fossil evidence also showed that these warmth-loving hippos lived alongside cold-climate animals like mammoths and woolly rhinos, an unusual ecological mix that highlights the complexity of Ice Age environments.

Rethinking Europe’s Ice Age Ecosystem

Dr. Patrick Arnold, the study’s lead author, explained that the findings show hippos did not vanish from Central Europe by the end of the last interglacial period as previously thought. Therefore, other European hippopotamus fossils traditionally attributed to the last interglacial period should be re-examined.

Professor Dr. Wilfried Rosendahl, General Director of the Reiss-Engelhorn-Museen and the “Ice Age Window in the Upper Rhine Graben” project, expressed confidence that Ice Age research still holds many intriguing questions: “The current study provides important new insights that impressively demonstrate the Ice Age was not uniform everywhere, but that local characteristics combined to form a complex overall picture, like a puzzle. It will now be important and necessary to examine other warmth-loving animal species that have so far been attributed to the last interglacial period.”

Conclusion

The research was conducted as part of the “Ice Age Window in the Upper Rhine Graben” project, supported by the Klaus Tschira Foundation Heidelberg. This multidisciplinary effort aims to shed light on the climate and environmental evolution of the Upper Rhine Graben and southwest Germany over the past 400,000 years. The study focused on Ice Age bones from the Reiss collection, preserved at the Reiss-Engelhorn-Museen, which continue to reveal fascinating insights into the dynamic prehistoric world of Europe.