The Duck-Billed Dinosaurs

       The several kinds of dinosaurs that have been given the name duck-billed dinosaurs were the true swimmers. They had some unusual physical structures that were very useful for their life in the water.

       Lambeosaurus (lamb-e-o-SAWR-us) had a long head and jaws that ended in a duck-like bill. He didn't have teeth in the front of his mouth, but on each side of his jaws were several rows of closely packed teeth. These teeth were somewhat like chisels fitted together tightly. Beneath these rows of teeth were other teeth already formed and ready to push up to replace each tooth as it wore down. He probably had as many as two thousand teeth during his life.

       Lambeosaurus had a hatchet-shaped bony extension from the top of his head. And still another duck-billed dinosaur called Parasaurolophus (par-a-sawr-AH-lof-us) had a long tubelike projection extending backward from his head. This projection may have been used as an air-storage chamber. When the duck-billed dinosaurs fed, they may have submerged in the water and used this reserve air-supply.

       The bodies of the different kinds of duck-billed dinosaurs were very similar in shape. Paleontologists find it difficult to tell the skeletons of different kinds apart until they have studied the skulls. The duck-billed dinosaurs developed many kinds of crests on their heads. These dinosaurs are best identified by studying their crests.

       Paleontologists have a very good idea of how the skin of the duck-billed dinosaurs must have looked. An impression of the skin of the dinosaur Edmontosaurus (ed-MONT-o-sawr-us) has been found. It shows that the skin was tough and leathery, with hundreds of horny scales covering it. An impression of the webbing between the toes of the front feet has also been found. Paleontologists therefore think that all duck-billed dinosaurs probably had this webbing, which was useful in paddling. These dinosaurs had the kind of tail that is useful in swimming - high and flattened at the sides. 

       Some of the duck-billed dinosaurs walked on their hind legs most of the time, but nevertheless they were able to bend over and put their front feet on the ground. They probably made quick dashes to the water to escape from the land-living dinosaurs, such as the fierce Tyrannosaurus. The duck-billed dinosaurs were all plant-eaters and fed on the plants growing on the banks of the rivers and lakes where they lived. Perhaps they used their duck-like bills to bite off the plants that grew in the shallow water.

       Fossil skeletons of plant-eating dinosaurs are relatively common in many parts of the world. In certain areas of the western United States so many skeletons of duck-billed dinosaurs have been found that we can assume that these dinosaurs lived there in herds. But the fossil skeletons of meat-eating dinosaurs are more rare. This scarcity may indicate that there were fewer of this kind of dinosaur. Today this relationship of plant-eaters to meat-eaters can be observed among animals that live in the same community. The predators are always fewer in number than the animals they prey upon.

Duck-billed dinosaurs were the true swimmers.