Europe's largest land mammal may be a hybrid of two extinct species.

Credit: Carole Fritz

Julien Soubrier and Alan Cooper at the University of Adelaide in Australia and their colleagues analysed mitochondrial DNA from 65 fossil specimens of bison, including the threatened European bison (Bison bonasus), ranging from 14,000 to more than 50,000 years old. They conclude that B. bonasus is a hybrid of two animals: the steppe bison (Bison priscus), the Eurasian ancestor of the American bison that became extinct more than 11,000 years ago, and the aurochs (Bos primigenius), the ancestor of modern cattle. The team estimates that the hybridization occurred at least 120,000 years ago.

Cave art seems to support the replacement of one species by another. Drawings dating to roughly 30,000–36,000 years ago showed animals resembling steppe bison (pictured), whereas art about 17,000–12,000 years old depicts animals similar to the European bison.

Nature Commun. 7, 13158 (2016)