The largest mammal with a single central horn on its head that ever lived was a prehistoric rhinoceros known scientifically as Elasmotherium, but colloquially referred to as the giant unicorn. The size of a mammoth, with a total height exceeding 2.5 m, a length sometimes exceeding 5 m, and a weight estimated at 5 tonnes, based upon fossil skeletal evidence palaeontologists believe that this colossal rhinoceros bore a single massive horn at least 2 m long positioned centrally upon the paired frontal bones constituting its brow. It survived until at least as recently as 50,000 years ago, during the Late Pleistocene in the Black Sea region of southern Russia, extending as far west as Siberia, and may even have lingered into historic times there.