Somewhere in North Africa, 97 million years ago, lived the Spinosaurus, a 50-foot-long predator that made the T-rex look puny. According to a report published Thursday in the journal Science, the Spinosaurus was “the biggest carnivorous dinosaur” but not a land animal. 150 million years of dinosaur history went by until “suddenly we see these adaptations in Spinosaurus where it is able to swim,” University of Chicago paleontologist Paul Sereno writes in the report. The dinosaur’s bones were found in a sandstone bed in the Sahara. It had a crocodile-like snout, paddle-like feet, and dense bones that helped with buoyancy and likely ate fish, ancient crocodiles, and whatever else it found in the water.