The plates along the back of a Stegosaurus were likely used to regulate heat.

The Stegosaurus lived during the Jurassic period, 159 million to 144 million years ago, and is known for its spiked tail and plated back.

Scientists have had different theories as to the purpose of the plates, but new discoveries suggest they were used to regulate the dinosaur’s temperature. They could both collect heat from the sun to keep them warm, and release heat to keep them cool.