If you think great white sharks are scary, you definitely wouldn’t have liked the Jurassic crocodiles that roamed the oceans 170 million years ago.
Up to 33 feet in length with large teeth, thalattosuchians evolved from their land-living crocodile ancestors. Over time, their limbs turned into flippers, their tails turned into flukes and their bodies became streamlined, making them fast-swimming killers.
Now, researchers have completed a study of the thalattosuchians’ skulls and found that they also adapted part of the inner ear as they adjusted to life in the oceans, mimicking the inner ears of whales and dolphins.
"The ancient aquatic crocs developed unusual inner ears after modifying their skeletons to become better swimmers,” Dr. Steve Brusatte, senior author on the study, said. “Whales also changed their ears in a similar way but did it soon after entering the water."
It is believed that each species mimicked each other's changes. "It seems like the crocs and whales took similar, but different, evolutionary routes from land to water," Brusatte added.
You can read more about the big predatory crocs in this CNN article.