Evolution and extinction
The ammonites came to an end 66 million years ago, during the planet's most recent mass extinction event. In the final days of the Cretaceous, a 7.5-mile-wide asteroid slammed into Earth and killed off more than three-quarters of all species on the planet.
When did ammonites become extinct?
The Jurassic Period began about 201 million years ago and the Cretaceous Period ended about 66 million years ago. The ammonites became extinct at the end of the Cretaceous, at roughly the same time as the dinosaurs disappeared.
Did ammonites go extinct with the dinosaurs?
Most ammonites died out at the same time as the non-avian dinosaurs, at the end of the Cretaceous Period, 66 million years ago.
