Hadrosaurs are some of the best known and most diverse (many different species) types of dinosaurs. There have even been large skin impressions found showing that hadrosaurs had small, button-like scales all over their bodies. They seem to be the deer of the Late Cretaceous. They were probably the prey of choice of the large meat-eating dinosaurs (the tyrannosaurs). They divide into two different groups, with the biggest difference between the groups being what their head looks like. The heads of the hadrosaurines were flat or had small spikes on the top. The heads of the lambeosaurines had big crests on them. Hadrosaurs had the most complicated, best designed teeth of all of the plant eating dinosaurs. They had up to 1200 teeth in their mouth at the same time. With all of these teeth, they could chew any plant material. This made them very successful as a group.


The "flat headed" dinosaurs were very common. They came in large varieties that fall into different groups. Some had very wide mouths with very long, flat heads (edmontosaurs), some had little spikes on the tops of their heads (saurolophs), and some had bumps on their noses (gryposaurs). It was the discovery of the hadrosaur Maiasaura that let palaeontologists know that hadrosaurs looked after their young in nests. Eggs, babies, and nests of Maiasaura were all found in the late 1970's in Montana showing a little bit about how baby dinosaurs grew up. Huge bonebeds have been found for several of the hadrosaurs, often with 10000 or more different dinosaurs in each!

Hadrosaurines ranged from 8 meters (Gryposaurus) to about 15 meters (Shantungosaurus) in length. They have been found in Asia, South America, North America, and Europe. True hadrosaurs include Gryposaurus, Maiasaura, Prosaurolophus, Shantungosuarus, Edmontosaurus, Saurolophus, Brachylophosaurus, Anatotitan, and Hadrosaurus.


Lambeosaurines are easy to spot when you are in the museum. They are the "duck-billed dinosaurs" with the big crests on their heads. There were not as many types of these, but they were quite plentiful. Some of the crests looked like big, flat, round disks on their heads. One was a great big long tube that faced backwards on the top of the head. These crests have been a mystery for years. At first, when people thought that hadrosaurs lived in the water, they were thought to be for breathing underwater. But, when they realised that hadrosaurs lived on land, ideas have changed. Some scientists think that they were used for smell. Some think that they were for making noise. Others think they were used for both. New clues from new specimens may help solve this mystery.

Lambeosaurines ranged in size from 6 meters (Bactrosaurus) to about 9 meters (Lambeosaurus). They have been found in Asia and North America. This group includes Lambeosaurus, Hypacrosaurus, Corythosaurus, Parasaurolophus, and Bactrosaurus.

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