According to most experts, the first mammal was Morganucodon, a small, shrew-like rodent that appeared during the Jurassic Period, approximately 200 million years ago. It weighed a few ounces and ...

Earth's earliest mammals spent their lives at a more leisurely pace than their modern counterparts, but they lived a lot longer, analysis of some 200-million-year-old teeth has shown. Earth's earliest ...

You can say this about mammals: We've had a good run. Over the 250 million years since the first mammals diverged from reptiles and birds, we hairy, warm-blooded vertebrates have come to dominate the ...

More than 220 million years ago, as early dinosaurs were just getting their legs under them, the first mammals evolved from a group of tiny, weasel-like reptiles called cynodonts. New research hints ...

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, ...

(CNN) — Before dinosaurs walked the Earth and tens of millions of years before the first mammals appeared, distant mammal relatives with long, serrated canine teeth were the dominant carnivores on ...