The biggest and the baddest among meat-eating dinosaurs, Spinosaurus may have also been the first dinosaur to take to the water, swimming in North Africa's rivers some 97 million years ago, researchers reported on Thursday.

Floating like a crocodile to stalk prey, the 50-foot-long (15.2 meters) predator bore a massive sail on its back that would have risen from the water like a shark's fin. The carnivore probably ate fish, ancient crocodiles, and anything else afloat.

"It was the biggest carnivorous dinosaur, but Spinosaurus wasn't a land animal," says University of Chicago paleontologist Nizar Ibrahim, a National Geographic Society Emerging Explorer who led the discovery of the new fossils. "This was a creature adapted to life in the water."

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