An international research team, led by the University of Potsdam, the Reiss-Engelhorn Museums Mannheim, and the Curt-Engelhorn Center for Archaeometry, has demonstrated through new bone analyses that hippopotamuses inhabited this region as recently as about 47,000 to 31,000 years ago. The findings, published in the journal Current Biology, challenge earlier assumptions regarding the extinction of these animals in Europe.
Hippopotamuses in the Upper Rhine Graben: Unexpected Discoveries
Until now, it was assumed that common hippopotamuses (Hippopotamus amphibius) went extinct in Central Europe around 115,000 years ago, at the end of the last warm period. However, the current study—with contributions from researchers at ETH Zurich and other international partners—reveals that hippopotamuses lived in the Upper Rhine Graben in southwestern Germany during the middle of the last Ice Age.
What the Bones Reveal: Dating and Analyses
The Upper Rhine Graben serves as an important continental climate archive. Animal bones preserved in gravel and sand deposits provide valuable insights into the past. “It is remarkable how well the bones have been preserved. We were able to extract meaningful samples from many skeletal remains—no small feat after such a long time,” emphasizes Dr. Ronny Friedrich, an expert in age determination at the Curt-Engelhorn Center for Archaeometry.
The team analyzed numerous hippopotamus finds using paleogenetic methods and radiocarbon dating. Sequencing of ancient DNA revealed that European Ice Age hippopotamuses are closely related to today’s African hippopotamuses and belong to the same species. The datings confirm their presence during a milder phase of the Middle Weichselian Ice Age.
A genome-wide analysis indicated very low genetic diversity, suggesting a small, isolated population in the Upper Rhine Graben. These results, together with other fossils, demonstrate that warmth-loving hippopotamuses lived alongside cold-adapted species such as mammoths and woolly rhinoceroses.
New Insights for Ice Age Research
“Our results show that hippopotamuses did not disappear from Central Europe at the end of the last warm period as previously thought,” summarizes lead author Dr. Patrick Arnold. “Therefore, other hippopotamus fossils traditionally assigned to the last warm period should be re-examined.”
Prof. Dr. Wilfried Rosendahl, General Director of the Reiss-Engelhorn Museums Mannheim and head of the “Ice Age Window Upper Rhine Graben” project, adds: “The study provides important insights and shows that the Ice Age was not uniform everywhere. Local variations combine to form a complex picture—much like a puzzle. It is both exciting and important to study other warmth-loving animal species, previously attributed to the last warm period, more closely.”
The study was conducted as part of the “Ice Age Window Upper Rhine Graben” project, funded by the Klaus Tschira Foundation Heidelberg. This interdisciplinary initiative investigates climate and environmental changes in the Upper Rhine Graben and southwestern Germany over the last 400,000 years. The research draws on Ice Age bone finds from the Reis collection, which is housed at the Reiss-Engelhorn Museums.
The full article in Current Biology can be found here.