<i>Spinosaurus</i> had cone-shaped teeth and raised nostrils like a crocodile.
Spinosaurus had cone-shaped teeth and raised nostrils like a crocodile.
Illustration by Franco Tempesta


Find out about the only known dinos that are thought to have spent time in water.

In a murky river that cuts through North Africa, a 50-foot-long hunter swims after a fish the size of a car. It sports six-inch-long teeth and a sail on its back with spines the size of surfboards. The hungry stalker closes in on the fish, gobbling up the meal. Then it glides away in search of more snacks. The creature isn’t some sort of enormous shark or a vicious crocodile. It’s a dinosaur called Spinosaurus, and it’s the only known dino that’s thought to have dwelled in water. 

Making waves

Named for its seven-foot-long spines, Spinosaurus lived about a hundred million years ago during the Cretaceous period. It inhabited what is now North Africa’s Sahara region, which at the time featured a large river system. Spinosaurus was well adapted for aquatic life. Its nostrils were further up on its snout than the nostrils of other dinosaurs. This would’ve allowed the animal to breathe even with most of its snout submerged. Its crocodile-like teeth were ideal for catching fish. 

The reptile’s dense bones—which resemble those of modern-day aquatic creatures such as the manatee—helped it float better. And its paddle-like webbed feet would’ve allowed the animal to swim. Even the dinosaur's sail—which likely stuck out of the water while Spinosaurus was swimming—helped the animal survive in its river home. 

Set sail 

Scientists believe that Spinosaurus may have used its sail as a warning signal to intruders. The sight of the sail jutting out of the water would tell others to back off—unless they wanted a fight. You wouldn’t want to mess with this splashy creature!