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A modern-day giant hippo (Hippopotamus amphibious) in water. Source: jwjarrett / Adobe Stock

Discovery of Tooth Reveals When Giant Hippos Roamed Britain

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Hippopotamus antiquus , or the European hippopotamus, is a now extinct species of giant hippo that once roamed Europe much before the last glacial period. In the much explored Westbury Cave, in  Somerset, a fossilized upper molar of the  hippopotamus antiquus  has been discovered, dated to between 1 and 2 million years ago. This discovery is the subject of a recently published open-access study in  The Journal of Quarterly Science .

Up until now, the earliest  fossil example of ancient giant hippo discovered in  Britain dated back 750,000 years, so this find at least doubles that figure, claims Neil Adams, the lead author of the study and PhD student at the University of Leicester. "The tooth closely matches other fossils belonging to the extinct species  Hippopotamus antiquus ,” wrote Adams on his  Twitter page.

The fossilized giant hippo (Hippopotamus antiquus) tooth discovered in Somerset. (Neil Adams / University of Leicester)

The fossilized giant hippo (Hippopotamus antiquus) tooth discovered in Somerset. (Neil Adams /  University of Leicester )

Europe Before the Last Ice Age and Continental Drift

With an average weight of 3 tons, or 3200 kilograms (7040 lbs), the  antiquus was double the size of the modern hippopotamus, known as the  hippopotamus amphibius . Previous examples of this species’  fossils have been found in France, Greece, and Germany, keeping in mind that at this time, Britain was connected to mainland Europe as a consequence of the Continental Drift.

"It is not only the first record of a hippo from the site, but also the first known hippo fossil from any site in Britain older than 750,000 years,” explained Adams. “The new hippo dates to a previously unrecognized warm period in the British fossil record”. Previously, the oldest records of hippos in Britain came from the East Anglian Crag Basin, where hippo remains have been recorded from numerous sites.

"Hippos are not only fabulous animals to find, but they also reveal evidence about past  climates," explained University of London paleontologist Danielle Schreve, co-author of the study. "Many  megafaunal species (those over a tonne in weight) are quite broadly tolerant of temperature fluctuations, but in contrast, we know modern hippos cannot cope with seasonally frozen water bodies,” she explained on the  University of Leicester  website.

The palaeoclimate at the time of the European hippopotamus was warm and humid, which is the general trajectory of the global climate right before the last  Ice Age . The authors of the study wrote that “… hippo may have been part of an early colonization of north-west Europe by these mega-herbivores… it evidences a currently cryptic northward migration during an even earlier temperate phase. In either case, the Siliceous Member is likely to represent a warm period that has not been recognized previously in the British Quaternary record.”

Map showing biogeography of giant hippos in western Europe during the late Early Pleistocene. (Adams et. al. / The Journal of Quarterly Science)

Map showing biogeography of giant hippos in western Europe during the late Early Pleistocene. (Adams et. al. /  The Journal of Quarterly Science )

The Challenges of Pre-Historic Reconstruction

The evidence of this period has been particularly difficult to reconstruct because of ice, water, and wind based erosion, caused by the coming and going of glacial cover and sheets both prior and after to the glacial period. It also takes the imagination to a time when the UK had warm and humid weather, a far-cry from the modern patterns of rain, wind, and cold, with occasional splatter of sunshine.

By studying the anatomy, and other evidence of the bodily structure and anatomy, experts can tell that  H. antiquus  lived an aquatically dominant lifestyle, much more than even its modern avatar. This is backed a larger body mass, on shorter legs, making it ideal for floating, with eyes for spying on the surface of the water – its eye sockets were positioned higher on the skull. It did not spend as much time wobbling around on grass trying to graze, which the modern hippo does, concludes  Science Alert .

The other logical conclusion that was drawn from the  H. antiquus’  aquatic habits was that frozen water bodies were obviously not a part of the general scenery. These would have prevented the ancient hippo from migrating and from floating in the water in order to feed on aquatic plants, keeping in mind that the hippopotamus is a mega-herbivore. This also implies that winters were mild, again contrary to modern-day winters in  Britain.

“Our research has demonstrated that in the  fossil record, hippos are only found in Britain during periods of climatic warmth, when summer temperatures were a little warmer than today but most importantly, winter temperatures were above freezing,” concluded Professor Schreve on the  University of Leicester  website.

Top image: A modern-day giant hippo (Hippopotamus amphibious) in water. Source:  jwjarrett / Adobe Stock

By Sahir Pandey

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