(CNN)Some 170 million years ago, deadly Jurassic crocodiles ruled the oceans. But researchers think they have unlocked the key to their successful reign of terror -- by mimicking the shape and senses of whales and dolphins.
Deadly ancient crocodiles imitated whales to dominate the oceans
The extinct beasts -- known as thalattosuchians -- could reach up to 10 meters in size and evolved from their land-living ancestors by adapting their limbs into flippers, developing fluked tails for swimming and streamlining their bodies, making them formidable, fast-swimming predators.
The teleosauroid Machimosaurus rex, the largest semi-aquatic thalattosuchian, could reach up to 10 meters in size, and is thought to have fed on hard prey like turtles due to its teeth, paleontologist Julia Schwab told CNN.
Plesiosuchus, the largest marine thalattosuchian that lived in the open ocean, measured about 6.8 meters and hunted anything from squid-like creatures to fish and other marine reptiles.
By studying the crocodile's skulls, researchers also found that they had adapted part of the inner ear as they adjusted to life in the oceans.
Paleontologists from the University of Edinburgh analyzed computerized axial tomography (CAT) scans of more than a dozen fossil skulls to study the vestibular system -- the three looping semicircular canals of the inner ear which control balance.
Researchers found that as the creatures entered their semi-aquatic phase, the canals started to become fatter and smaller like those of whales and dolphins.