North American Dinosaurs

Maiasaura peeblesorum - North American Dinosaurs

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(mah-ee-SAWR-uh) - "good mother lizard"

Describer Horner and Makela, 1979
Also Known As --
Type of Species peeblesorum
Order Ornithischia
SubOrder Ornithopoda
InfraOrder --
Micro-Order --
Family Hadrosauridae
Size 30 feet (9 meters) in length
Period Late Cretaceous, 80 million years ago
Fossilsite North America, Montana, US
Diet Herbivore

Maiasaura peeblesorum Maiasaura was a large, herbivore, duck billed dinosaur with a flat skull and small crests in front of the eyes. It had a toothless beak, with cheek pouches and and a thick nose. Each hand had four fingers and the feet had hoof like claws. Maiasauras measured 30 feet (9 meters) long, 6-8 feet (2-2.5 meters) tall, weighing 3-4 tons. Newly hatched Maiasaura babies were about 1 foot (30 cm) long. Maiasauras were the first dinosaurs to be found alongside their young, eggs, and nests. It lived in herds and it raised its young in these nesting colonies. The nests, containing 30 to 40 eggs, were made of Earth, and were guarded by the parents. The eggs had about the size of ostrich. Its newborns were about a 1 foot (0.3 meter) long. Nests are about 25-30 feet apart, just about the size of an adult Maiasaura. In Montana, one group of over 40 nests covers 2.5 acres of land that was an island during the late Cretaceous. It seems it lived in large herds, some that may have contained as many as 10,000 animals. With so many mouths to feed, the search for food was a continual process, and scientist believe that the Maiasaura herds migrated along well known routes throughout the seasons of the year, always knowing the best places were find adequate supplies of food.
Maiasaura lived during the late Cretaceous period, about 80 to 65 million years ago. Other carnivore dinosaurs of its time were Velociraptor, Albertosaurus, Troodon, Tyrannosaurus rex, Ankylosaurus, Parasaurolophus, Corythosaurus, and Dryptosaurus.

Maiasaura peeblesorum Maiasaura was both a quadripedal and bipedal, and was a relatively fast dinosaur. Maiasaura's front legs were much shorter than the rear legs. it had no defense against carnivores, excepting, perhaps, its heavy muscular tail and its herd behavior. Running was their only means of escaping carnivores such as Albertosaurus and Troodon.

Maiasaura was an herbivore. An adult of this size would need to eat about 200 pounds per day. The existence of herds might also suggest the necessity of seasonal migratory movements to feed such a large group of animals.


Discovery
Maiasaura was discovered by dinosaur paleontologist Jack Horner. He named the dinosaur after a series of nests with remains of eggshells and hatchlings. This was the first prove of giant dinosaurs raising and feeding their young. Over 200 specimens, adults, hatchlings, juveniles, nests, eggs and embryos have been found. Maiasaura was first discovered in Montana, USA.