More than half of all mammal species are rodents, a group that includes squirrels, hamsters, mice and guinea pigs. Rodents have long, sharp front teeth that they use for biting and gnawing.

The new research is the first to look back at early mammals in full color. Using advanced fossil imaging methods and a thorough examination of the pigment-producing cells present in living mammals, ...

During the age of dinosaurs, early mammals probably lacked the stripes and spots of their modern relatives, having uniformly dark, drab coats.