Large reptiles were successful predators, snapping up fish, mollusks and smaller reptiles.
Ancient sea monsters had more than just sharp teeth and fearsome size on their side. They were able to chase down prey thanks to an even, warm body temperature that kept their muscles humming even in cold water, a new study finds.
Researchers analyzed fossilized teeth of three groups of reptiles that lived from 251 million to 65 million years ago in the Mesozoic era. The chemical makeup of the teeth differed subtly from those of cold-blooded fishes that lived during the same times and places, suggesting the reptiles retained heat like modern tuna and some species of shark (and unlike today’s crocodiles and alligators).
"The only way to maintain a constant and high body temperature is that the animal is able to produce internal heat by its organs," said study researcher Christophe Lecuyer of the University of Lyon in France. "It was probably very useful for them to dive in deep waters to track prey and also to have access to environments where normal reptiles cannot go."
IN PICTURES: Monsters of the deep
The finding helps explain why these large reptiles – dolphin-shaped icthyosarus, sea lion-like plesiosaurs and elongated mosasaurs – were such successful predators, snapping up fish, mollusks and smaller reptiles. By maintaining a relatively warm body temperature, the biochemical reactions powering their muscles would have operated more efficiently.