Hadrosaurs (HAD-roh-sawrs) didn’t moo. And they definitely didn’t make milk! But they’re sometimes called the “cows of the Cretaceous.” That’s because they were built for chewing lots and lots of plants—just as cows are. (The Cretaceous period is the time when hadrosaurs lived.)

Most hadrosaurs had long, flat beaks. Many people call them “duck-billed dinosaurs.”

Some hadrosaurs, such as Hypacrosaurus, had tall crests on the tops of their heads. Others, such as Gryposaurus, had no crests at all.

The name “hadrosaur” means “bulky lizard.” Can you see why?

Hadrosaurs lived in jungles, forests, and swamps, and on plains and beaches, all over the world.