Maiasaura peeblesorum - Cretaceous 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 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
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.