Iguanodon

Iguanodon was one of the very first dinosaurs to be given a name. It was discovered in 1822 in England. Its name means "iguana tooth" because its teeth looked like a big iguana's teeth. It lived about 125 million years ago.

Thumb Spikes

Iguanodon's most famous feature is the big spike on each thumb. These spikes were about 6 inches long. Scientists think they were used for defense against predators. At first, scientists thought the spike went on its nose like a horn! They later figured out it was a thumb.

A Versatile Dinosaur

Iguanodon was about 33 feet long and weighed about 4 tons. It could walk on two legs or four legs. It used its beak to bite off plants. Behind the beak, it had rows of grinding teeth. Iguanodon lived in herds across Europe, North America, and Africa.

Fun Facts

• When first discovered, scientists thought Iguanodon walked on four legs like a lizard.
• Its thumb spike was first placed on its nose like a rhinoceros horn.
• Iguanodon was only the second dinosaur ever to get a scientific name.

Did You Know?

In 1878, miners in Belgium found over 30 Iguanodon skeletons deep underground in a coal mine. It was one of the greatest dinosaur discoveries ever!