Dinosaurs have been fearsome and fascinating — but tragic? When science said dinosaurs were pea-brained and cold-blooded, humans took their demise as proof of the superiority of warm, clever mammals.

Scientists still debate the purpose of this dinosaur's iconic horns and spiky head plate. Find out what we’ve learned about how Triceratops lived and why it went extinct.

Dinosaurs dominated Earth for more than 160 million years, evolving into countless forms and becoming the planet's most successful land animals. But despite their incredible success, they disappeared ...