Jurassic critters from China shed light on mammal origins

An illustrated reconstruction shows one of the three newly described mammal species, Xianshou songae, at the American Museum of Natural History.

Newly discovered fossils in China indicate that mammals were tiny squirrel-like critters living in the shadows of the dinosaurs.

It may not have been the friendliest place for furry little creatures, but three newly identified squirrel-like mammals thrived in the trees of the Jurassic Period, with dinosaurs walking below and flying reptiles soaring above.