Stegosaurus

Stegosaurus was a large, herbivorous dinosaur that lived during the Late Jurassic period, about 150 million years ago. It is easily recognized by the distinctive double row of large, bony plates along its back and the spiked tail, known as the thagomizer, used for defense. Stegosaurus was about 30 feet long and weighed over two tons. Despite its size, its brain was relatively small, similar in size to a walnut. This dinosaur likely fed on low-lying plants and may have used its body armor and tail spikes to protect itself from predators.