Mosasaurus: 15-Meter Marine Lizard, Not a Dinosaur
Mosasaurus reached 15 to 18 meters in Late Cretaceous seas 82 to 66 million years ago, a giant lizard.
Giant lizard of the seaway
Mosasaurus measured 15 to 18 meters long and weighed up to 14 tonnes, living in the Late Cretaceous 82 to 66 million years ago. It was a giant monitor-lizard relative, not a dinosaur, hunting in the warm Western Interior Seaway.
Its double-hinged jaws opened extremely wide and held a second row of teeth on the palate. This trap gripped slippery prey, while forward teeth pierced 10-centimeter-thick shells and bones of large marine animals.
Birth, growth and hunting
Mosasaurus gave live birth in open water, babies emerged tail-first and swam at once. Fossils show fast growth to 10 meters within years, with adults ruling seas 16 million years until the asteroid impact.
Powerful trunk muscles drove ambush attacks at 30 kilometers per hour in short bursts. Scarred bones and stomach contents reveal sharks, birds and smaller mosasaurs eaten whole, making it the top Cretaceous marine predator.
- Length 15 to 18 meters, weight 14 tonnes.
- Giant monitor-lizard relative, not dinosaur.
- Lived 82 to 66 million years ago.
- Double-hinged jaws plus second teeth row.
- Gave live birth in Western Interior Seaway.