A small, isolated population of common hippos (Hippopotamus amphibius) was present in the Upper Rhine Graben in southwestern Germany during the middle Weichselian, a period spanning from 47,000 until 31,000 years ago, according to new research.
Radiocarbon dating reveals the mid-Weichselian presence of common hippos (Hippopotamus amphibius) in the Upper Rhine Graben in Germany. Image credit: Gemini AI.
Hippos colonized Europe from Africa in multiple waves, probably by multiple species of the genus Hippopotamus, including the common hippo that is only found in sub-Saharan Africa.
During their maximum geographic distribution in Europe, hippos ranged from the British Isles in the northwest to the Iberian and Italian peninsulas in the south.
Their presence in the fossil record generally implies temperate conditions with denser vegetation and open water bodies.
Their origin and relationships to living African common hippos and the exact age of their extinction in central Europe, however, still remain unclear.
“Until now, it was believed that common hippos became extinct in central Europe around 115,000 years ago, with the end of the last interglacial period,” said co-senior author Professor Wilfried Rosendahl, general director of the Reiss-Engelhorn-Museen Mannheim.
“Our study demonstrates that hippos inhabited the Upper Rhine Graben in southwestern Germany sometime between approximately 47,000 and 31,000 years ago.”
In the study, Professor Rosendahl and colleagues examined 19 hippo specimens from fossil localities of the Upper Rhine Graben.
“The Upper Rhine Graben is an important continental climate archive,” said study co-author Dr. Ronny Friedrich, a researcher at the Curt-Engelhorn-Zentrum Archäometrie.
“Animal bones that have survived for thousands of years in gravel and sand deposits are a valuable source for research.”
“It’s amazing how well the bones have been preserved,” he added.
“At many skeletal remains it was possible to take samples suitable for analysis — that is not a given after such a long time.”
The team’s analysis of ancient DNA showed that European Ice Age hippos are closely related to living African hippos and belong to the same species.
The radiocarbon dating confirmed their presence during a milder climatic phase in the middle Weichselian.
An additional genome-wide analysis indicated very low genetic diversity, suggesting that the population in the Upper Rhine Graben was small and isolated.
These results and further fossil evidence show that heat-loving hippos appeared in the same time frame as species adapted to cold temperatures, such as mammoths and woolly rhinos.
“The results demonstrate that hippos did not vanish from middle Europe at the end of the last interglacial, as previously assumed,” said study first author Dr. Patrick Arnold, a researcher at the University of Potsdam.
“Therefore, we should re-analyze other continental European hippo fossils traditionally attributed to the last interglacial period.”
“The current study provides important new insights which impressively prove that the Ice Age was not the same everywhere, but local peculiarities taken together form a complex overall picture — similar to a puzzle,” Professor Rosendahl said.
“It would now be interesting and important to further examine other heat-loving animal species, attributed so far to the last interglacial.”
The results were published on October 8, 2025 in the journal Current Biology.
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Patrick Arnold et al. Ancient DNA and dating evidence for the dispersal of hippos into central Europe during the last glacial. Current Biology, published online October 8, 2025; doi: 10.1016/j.cub.2025.09.035
