Spinosaurus had a giant skin-covered sail sticking out of its back. Some other spinosaurs had sails, too. Still others had bumps or ridges. Scientists aren’t sure why. It’s a big mystery!

Under the skin, a sail was made of long, flat parts of the backbone called spines. That’s how Spinosaurus got its name.

Spinosaurus is long gone. But you can still see an animal with long spines and a skin-covered sail: the crested chameleon! It lives in the jungles of central Africa.

Why a sail?

1. Many scientists think Spinosaurus used its sail like a billboard to “talk” or show off to other dinosaurs.
2. Some scientists think Spinosaurus used its sail to warm up during cool times and cool off during warm times.
3. A few scientists think Spinosaurus kept lots of fat in its sail to get energy when it couldn’t find food.