A newly discovered prehistoric mammal may hold clues to how life survived the dinosaur-killing extinction. The tiny species, Cimolodon desosai, lived 75 million years ago and had traits—like a small body and varied diet—that likely boosted survival odds. Found in Baja California, the fossil includes rare skeletal remains that reveal how it moved and lived. Researchers believe its lineage helped mammals endure one of Earth’s deadliest events.