Hippos are the ultimate party animals of the animal world– follow them, and you’ll find heat and water. Today, they live primarily in the lakes and rivers of Africa, where they wallow as the second-largest land animal in the world. According to a brand-new research study, these large animals once roamed north into Europe and adapted to changes in the continent’s glaciers.
The fact that modern hippos, Hippopotamus amphibius, once lived in Europe is established science. What scientists still don’t know is how they migrated from Africa and their relationship to the long-extinct Hippopotamus antiquus, which may have inhabited Europe at the same time.
Scientists also debate when modern hippos first arrived, but the reconstruction and dating of a crucial hippo skull discovered in Rome, Italy, offers a new answer.
In restoring the skull and jaws, researchers found some ancient dirt attached to the teeth and mandible of an ancient hippo. They traced the dirt’s composition to the local Valle Guilia geological formation, which contains sediment between 560,000 years and 460,000 years old.
Therefore the hippo would have lived about 500,000 years ago, during the Early-Middle Pleistocene Transition.
At this time, the world’s climate underwent significant changes that resulted in longer glacial periods that put the world into deep freeze and created very thick ice sheets. When these glaciers advanced, hippos likely sought refuge in modern Spain, Italy, and the Balkan Peninsula where conditions were relatively mild. According to research, the last hippos to live on the Italian Peninsula likely died between 128,000 years and 73,000 years ago.
When the scientists began working with the hippo fossils, they were lacking some crucial information– where they had originated from. The original label attached to the specimen had been lost, and the catalog held by the Earth Science University Museum at the Sapienza University of Rome contained no location information nor the date of acquisition.
The group used previous research along with old maps and photographs to narrow the location to a former gravel quarry, Cava Montanari, that had operated during the second half of the 19th Century. Today, a riding school sits near the area, which is surrounded by the Tor di Quinto district of Rome.
Closeby runs the Tiber River, which is the modern expression of an ancient waterway that likely produced the sediment collected from the hippo skull.
