Scientists rethink why giant insects once ruled the skies, finding oxygen may not explain their size or disappearance.

Three hundred million years ago, dragonfly-like creatures with wingspans stretching 70 centimeters patrolled the skies of a ...

Learn how ancient oxygen levels in the Paleozoic era were linked to giant insect size, and why that theory is now being ...

Millions of years ago, oversized insects such as griffinflies boasting wingspans comparable to today's hawks scuttled across (and fluttered above) the planet. But why these jumbo jets of the insect ...

Three-hundred-million years ago, Earth was very different. The continents had coalesced into Pangea, which was dominated in its equatorial regions by vast coal-swamp forests. With high atmospheric ...