Until now, it was believed that common hippos (Hippopotamus amphibius) became extinct in central Europe around 115,000 years ago, with the end of the last interglacial period. A new study, conducted by researchers from the University of Potsdam, the Reiss-Engelhorn-Museen Mannheim, the Curt-Engelhorn-Zentrum Archäometrie Mannheim, ETH Zurich and international partners, demonstrates that hippos inhabited the Upper Rhine Graben in southwestern Germany sometime between approximately 47,000 and 31,000 years ago, i.e. during the middle of the last ice age.
The Upper Rhine Graben is an important continental climate archive. 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. At many skeletal remains it was possible to take samples suitable for analysis – that is not a given after such a long time,” emphasizes Dr. Ronny Friedrich, expert in age determination at the Curt-Engelhorn-Zentrum Archäometrie.
The team examined numerous hippopotamus finds and combined paleogenomic and radiocarbon analyses. Ancient DNA sequencing showed that European ice age hippos are closely related to African hippos living today and belong to the same species. Radiocarbon dating confirmed their presence during a milder climatic phase in the middle Weichselian glaciation.
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,” summarizes first author Dr. Patrick Arnold. “Therefore, we should re-analyze other continental European hippo fossils traditionally attributed to the last interglacial period.”
Prof. Dr. Wilfried Rosendahl, general director of the Reiss-Engelhorn-Museen Mannheim and project leader of “Eiszeitfenster Oberrheingraben” is convinced that ice age research still holds many exciting questions: “The current study provides important new insights which impressively prove that ice age was not the same everywhere, but local peculiarities taken together form a complex overall picture – similar to a puzzle. It would now be interesting and important to further examine other heat-loving animal species, attributed so far to the last interglacial.”
The study was conducted within the framework of the project “Eiszeitfenster Oberrheingraben”, funded by the Klaus Tschira Stiftung Heidelberg. The interdisciplinary project contributes to understanding climate and environmental developments in the Upper Rhine Graben and southwestern Germany over the last 400,000 years. Objects of investigation are ice age bone finds from the Reis collection, located at the Reiss-Engelhorn-Museen.
The publication online: Arnold et al., 2025, Ancient DNA and dating evidence for the dispersal of hippos into central Europe during the last glacial, Current Biology 35, 1–9: https://www.cell.com/current-biology/fulltext/S0960-9822(25)01205-9
Photos:
2025_091_NK24_Hippo_Mandible_rem: Left mandible fragment of a female hippopotamus from Reiss-Engelhorn-Museen Mannheim, Slg. Reis Hippopotamus sp. Age dating: Between 46,000 and 48,300 years ago. Location: Bobenheim-Roxheim, Rhine-Palatinate district. Photo: Rebecca Kind
2025_091_EISZEIT300_Flusspferd_rem: Hippos lived at the Upper Rhine in the same time frame as mammoths. In the Reiss-Engelhorn-Museen a hippo reconstruction meets a mammoth skeleton. Photo: Rebecca Kind
Contact:
Dr. Patrick Arnold, Institute of Biochemistry and Biology, University of Potsdam
Tel.: 0331/977-5437
E-Mail: patrickarnolduuni-potsdampde
Prof. Dr. Wilfried Rosendahl, Reiss-Engelhorn-Museen Mannheim
Tel.: 0621/293-3172
E-Mail: wilfried.rosendahlumannheimpde
Dr. Ronny Friedrich, Curt-Engelhorn-Zentrum Archäometrie
Tel.: 0621/293-3835
E-Mail: ronny.friedrichucezapde
Media Information 09-10-2025 / Nr. 091