Chinchillas and cows don’t have a lot in common—or at least they don’t in their current incarnations. But 32.5 million years ago in the grasslands of the Chilean Andes they did, according to a new study of the tiny bones left behind by an extinct—but newly discovered—chinchilla species. Known formally as Andemys Termasi—or mouse of the Andes—the animal had to cope with the same challenge cows, goats, horses and other hooved animals do: how to chew the tough grasses that make up the principal food in their natural habitat without wearing down their teeth. The hooved beasts have always gotten credit for inventing the trait known as hypsodonty—or high, crowned molars that work like a powerful mortar and pestle. But new fossil analyses by a U.S. team led by the American Museum of Natural History revealed that the Andemys Termasi got there first. What’s more, the little animal figured out how to grow cow teeth in the back of its mouth without sacrificing its longer, more familiar rodent teeth up front. Versatility in all things—including dental work—pays off again.