Mammals May Explain Why Tiny Dinosaurs Were Rare

The Story in Brief

Dinosaurs appeared about 230 million years ago and became the dominant land animals before an asteroid struck Earth 66 million years ago, causing a mass extinction. A report by NDTV examines whether mammals played a role in the scarcity of tiny dinosaur species. The question concerns how dinosaurs and early mammals shared ancient ecosystems, although the available account does not establish that mammals were the cause.

Dinosaurs held sway on land for most of their history, but their reign ended with the asteroid impact. The report presents the mammal theory as a possibility, not a settled explanation for dinosaur body sizes.