Before dinosaurs vanished, a hamster-sized mammal was already shaping what survived next on the Pacific Coast

Mammals and dinosaurs coexisted on Earth until a catastrophic event 66 million years ago killed 75% of life on the planet. Despite the devastation, some animals survived, including rodent-like mammals in the Cimolodon genus. These creatures are part of the multituberculates, a group that arose during the Jurassic Period and survived over 100 million years before going extinct. Studying these animals helps researchers better understand how mammals survived the mass extinction event and then diversified into the variety of mammals around today.