Middle School
Worksheets
Spinosaurus: A Sail or a Hump?
Spinosaurus (spy-no-SORE-uss) was a type of sail-backed dinosaur. Its name means "spine lizard," named for the row of tall, bony spines that stuck up along its backbone, and these spines were probably covered with a sheet of skin. It must have looked like a large ship's sail on the dinosaur's back, and the sail was six feet tall! Several kinds of dinosaurs had sails, but Spinosaurus is the largest dinosaur of this type that has ever been found.
Scientists aren't sure what the purpose of the sail was, but the best guess is that the sail may have helped regulate body temperature. On cold days, perhaps Spinosaurus stood so that the sail could get the most sunlight. Blood passing through blood vessels in the thin skin on the sail would have been warmed, and as it was pumped through the dinosaur's body, it spread the warmth. On hot days, Spinosaurus could cool its body by moving into the shade.
Another idea is that the sail might have been a colorful display used to attract mates like the bright feathers of a peacock's tail, and it also may have been used to scare away other predators. The large sail would have made this giant dinosaur look even larger!
