Overview
Stegosaurus is one of the most iconic dinosaurs of the Jurassic period, instantly recognisable by the two rows of kite-shaped plates running down its back and the four sharp spikes — called a thagomizer — at the tip of its tail. The function of those plates has been debated for over a century: thermal regulation, display, and species recognition have all been proposed.
Key fact
Its brain was roughly the size of a walnut — about 80 grams — giving it one of the lowest brain-to-body ratios of any dinosaur.
Did you know?
- The tail spikes — the 'thagomizer' — were named after a Far Side cartoon in 1982, and the name stuck in science.
- Back plates may have flushed with colour by pumping blood — like a built-in display board.
- Despite its size, it moved slowly and grazed low-lying plants.
- Lived alongside Allosaurus, which preyed upon it.