BERLIN (AP) — Scientists say they have unlocked the evolutionary origins of the European bison — and solved a riddle posed by Stone Age cave art in the process.

European bison, also known as wisent, first appeared seemingly out of nowhere almost 12,000 years ago and are distinct from their American counterpart. Previous genetic analysis indicated that both species descend from the steppe bison, which roamed throughout Eurasia and North America until becoming extinct about 9,000 years ago.

By analyzing DNA samples taken from ancient bison remains researchers discovered a previously unknown species that emerged when male steppe bison bred with female Aurochs, the extinct ancestors of modern cattle, at least 120,000 years ago.

"It is unexpected that such a hybridization event would give rise to a new species out-competing both its parent species, probably by adapting better to environmental changes at the time," said Julien Soubrier, a researcher at the University of Adelaide, Australia. Soubrier co-authored the study published online Tuesday by the journal Nature Communications.

The hybrid eventually evolved into the present-day wisent, the researchers concluded.

Filling in the gap in the wisent's evolutionary history also helped answer why ancient humans painted two distinct types of bison on the walls of European caves, said Soubrier. Stone Age hunters were painting long-horned steppe bison and an early, short-horned form of wisent, which coexisted in Europe for tens of thousands of years. The two species predominated at different times depending on climate.

Hans Lenstra, an animal geneticist at Utrecht University in the Netherlands who wasn't involved in the study, said its findings appeared sound and should serve to underline the importance of preserving even hybrid species.

These days wisent are found mainly in Poland, where they were saved from extinction in the early 20th century. Since then Europe's largest land animal has been slowly reintroduced to various parts of the continent.