For more than a decade, researchers have been scratching their heads at strange results from genetic studies of late ice age bison bones and teeth that have hinted at an undiscovered extinct species. They call this elusive beast the “Higgs bison” after the Higgs boson particle that was finally discovered after 48 years of speculation. In the genetic studies, researchers noticed that some sections of ancient steppe bison genomes seemed out of place, as if they belonged to another species. But the evidence was never strong enough to declare the Higgs bison’s existence. Now, French cave scientists have pointed these researchers to what might give them the answer—early cave art in the Lascaux and Pergouset caves in France. There, cave art from between 18,000 and 22,000 years ago shows animals with distinct steppe bison features: long horns and hefty, robust forequarters (above). But about 5000 years later, that depiction changes to show bison with balanced body proportions and smaller, thinner horns. That shift in features could signify that an entirely different species was roaming the chilly European grasslands at that time, the researchers write today in Nature Communications. To confirm this, they sequenced the mitochondrial and nuclear DNA from bison bones and teeth from 20 sites across Europe, the Urals, and the Caucasus dating to between 12,000 and 22,000 years old. They were astounded to find that not only did a separate species appear between 13,000 and 17,000 years ago, but that it was the hybrid offspring of the steppe bison—whose descendants include today’s American bison—and another extinct cowlike mammal called the aurochs. And the new hybrid seems to have had an evolutionary advantage over its parents: The scientists speculate that the Higgs bison outlived both groups to itself give rise to today’s European bison.