Gator Breath May Explain How Dinosaurs Ruled The Earth

New insights into the breathing habits of alligators may explain how the dinosaurs' ancestors thrived after a Permian-Triassic extinction that eradicated 70% of all land life and 96% of all sea life some 251 million years ago.

A University of Utah study published in tomorrow's Science discusses how the structure of alligators' lungs may have allowed the dinosaurs' archosaur ancestors to survive Earth's low oxygen environment after "The Great Dying," a massive extinction which killed off most of the synapsids, reptilian precursors to the dinosaurs that eventually evolved into mammals. According to Utah researcher C.G. Farmer,

"A few of the synapsids survived the mass extinction to re-establish their dominance in the early Triassic, and the lineage eventually gave rise to mammals in the Late Triassic," says Farmer. "However, the recovery of life in the aftermath of the extinction involved a gradual turnover of the dominant terrestrial vertebrate lineage, with the archosaurs supplanting the synapsids by the Late Triassic."

From then until the dinosaurs died out 65 million years ago, any land animal longer than about 3 feet was an archosaur, says Farmer, while mammal-like synapsid survivors "were teeny little things hiding in cracks. It was not until the die-off of the large dinosaurs 65 million years ago that mammals made a comeback and started occupying body sizes larger than an opossum."

Had the Permian-Triassic extinction not occurred (and oxygen levels dipped to 12% as opposed to 21% today), it'd be intriguing to see what sort of proto-mammalian forms could've evolved. Heck, had "The Great Extinction" never occurred, I'm betting we'd be sitting pretty with some Kryptonian-grade superpowers by now.

[via The University of Utah]