Research published in Current Biology moved the last known appearance of hippopotamuses in Central Europe forward by tens of thousands of years. An international team led by Patrick Arnold of the University of Potsdam and Wilfried Rosendahl of the Reiss-Engelhorn-Museen Mannheim found that Hippopotamus amphibius occupied the Upper Rhine Graben between about 47,000 and 31,000 years ago, squarely within the last Ice Age. Radiocarbon dating of 19 fossils, supported by paleogenomic data, overturned the long-accepted view that the animals vanished from the region roughly 115,000 years ago at the end of the Eemian interglacial.
“It’s amazing how well the bones have been preserved,” said Ronny Friedrich, whose laboratory produced the radiocarbon dates, according to Phys.org. Friedrich added that many remains still yielded material suitable for analysis even though conventional wisdom holds that radiocarbon dating rarely works beyond 60,000 years.
Genetic information extracted from one fossil linked the Ice Age hippos to modern African Hippopotamus amphibius and revealed very low genetic diversity, indicating a small, isolated population. At its widest range, the species stretched from the British Isles to Iberia, but climate shifts gradually confined it to scattered refuges.
“The results show that hippopotamuses did not disappear from Central Europe at the end of the last warm period as previously assumed,” said Arnold, according to Phys.org. He called for a fresh examination of other European hippo fossils traditionally assigned to the Eemian.
The gravel and sand deposits of the 350-kilometer-long Upper Rhine Graben have long preserved Late Pleistocene fauna. The Eiszeitfenster Oberrheingraben (Ice Age Window Upper Rhine Graben) project, funded by the Klaus Tschira Stiftung Heidelberg, uses that archive to reconstruct 400,000 years of environmental change.
Professor Rosendahl noted that the findings “demonstrate that the Ice Age was not the same everywhere, but that local peculiarities together form a complex overall picture—similar to a puzzle,” according to Phys.org.
Fossil layers show that hippos lived alongside cold-adapted woolly mammoths and woolly rhinoceroses during brief warm interstadials. Their presence signals pockets of humid, temperate conditions within the broader glacial landscape and underscores the climatic mosaic of Late Pleistocene Europe.
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