Researchers have long known that many dinosaurs had bold patterns and bright, sometimes flashy feathers—far from the grayish, scaly monsters we often see in movies. Now, a new study of Chinese fossils published today in Science reveals the coloration of some of the early mammals that coexisted with dinosaurs. They were clad in dark brown or grayish fur—a trait that may have played a key role in their survival up to the present.

The new finding also reinforces the idea that “mammals were living in the shadow of the dinosaurs, quite literally” and likely lived nocturnal lifestyles to avoid unwanted attention.