Long ago, before the dinosaurs, there was a time when protomammals prospered. These early ancestors of ours were some of the most ecologically-significant animals on the planet, filling landscapes to the brim with various herbivores, carnivores and omnivores during what paleontologists know as the Permian Period.
A mass extinction changed all that.
About 252 million years ago, intense volcanic activity sparked Earth’s third mass extinction. Roughly 70 percent of known species quickly perished, including most protomammals. Reptiles fared better during the aftermath, the early relatives of crocodiles, dinosaurs, and other scaly creatures diversifying into a spectacular array of shapes and sizes.
Now paleontologists are starting to understand how the Age of Reptiles got its start.
