Cretaceous Fur Ball: Ancient Mammal With Spiky Hair Discovered

The fossilized remains of a furry critter that once roamed the Earth alongside dinosaurs suggests that mammals have been growing hair the same way for at least 125 million years. The Spinolestes specimen is special because it was fossilized with so many of its parts intact, Luo told Live Science in an email. Before the fossil was unearthed by paleontologists in Spain, the oldest mammalian bones containing similar, hair-related microstructures dated back just 60 million years.