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Maiasaura was a large, plant-eating, duck-billed dinosaur. Maiasaura was the first dinosaur that was found alongside its young, eggs, and nests. This suggests that Maiasaura nurtured its young.

ANATOMY
Maiasaura was a duck-billed dinosaur with a flat skull and small crests in front of the eyes. This plant-eater had a toothless beak, cheek pouches, and many self-sharpening cheek teeth; hard enamel was found on both the outer surface of the upper teeth and the inner surface of the lower teeth. The hands each had four fingers and the feet had hoof-like claws.

Maiasauras grew to be about 30 feet long (9 m), 6-8 feet tall (2-2.5 m), weighing roughly 3-4 tons. Newly hatched Maiasaura babies were about 1 foot (30 cm) long.

MAIASAURAS' SOCIAL BEHAVIOR
Maiasauras are the first dinosaurs to be found alongside their young, eggs, and nests. This suggests that they nurtured their young. The nests were holes scooped out of the ground, about 6-7 feet in diameter (1.8-2 m), and contained up to 25 grapefruit-sized eggs each. Newborns were about a foot (0.3 m) 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 (1 hectare) of land that was an island during the late Cretaceous.

In Montana, Maiasaura fossils have been found in a huge group of about 10,000, strongly suggesting herding behavior. These Maiasauras were buried in volcanic ash. The existence of herds might also suggest the necessity of seasonal migratory movements to feed such a large group of animals.

WHEN MAIASAURA LIVED
Maiasaura lived during the late Cretaceous period, about 80 to 65 million years ago, toward the end of the Mesozoic, the Age of Reptiles. It was among the last of the dinosaur species to evolve before the Cretaceous-Tertiary extinction 65 million years ago. Among the contemporaries of Maiasaura were Velociraptor, Albertosaurus and Troodon (carnivores that probably preyed upon Maiasauras), Tyrannosaurus rex (a larger version of Albertosaurus), Ankylosaurus (an armored herbivore), Parasaurolophus, Corythosaurus (a crested dinosaur), and Dryptosaurus (a meat-eating dinosaur).

INTELLIGENCE
Maiasaura was an ornithopod, whose intelligence (as measured by its relative brain to body weight, or EQ) was midway among the dinosaurs.

LOCOMOTION

A Hadrosaur footprint.

Maiasaura walked on four legs, and was a relatively fast dinosaur. Maiasaura's front legs were much shorter than the rear legs. When they ran, they probably used only their back legs, with the tail providing balance. Running was their only means of escaping carnivores like Albertosaurus and Troodon.

DISCOVERY OF FOSSILS
Maiasaura was first discovered in Montana, USA. Thousands of Maiasaura fossils have been found in western Canada and the United States. Adults, hatchlings, juveniles, nests, eggs and embryos have been found. One huge bonebed in Montana (dubbed Egg Mountain) contained thousands of fossils; it was found by Marion Brandvold and her son David Trexler. Maiasaura was named by Jack R. Horner and Robert Makela in 1979. Laurie Trexler found the holotype of Maiasaura peeblesorum (the type species) and Marion Brandvold found the fossilized eggs.

CLASSIFICATION
Maiasaura was a late Ornithischian dinosaur, the order of bird-hipped, herbivorous dinosaurs. It was a member of the suborder Ornithopoda, and the family of duck-billed, herding herbivores, the Hadrosaurs.

MAIASAURA ACTIVITIES

• A labeled Maiasaura printout
• Print out a K-3 Maiasaura information page to color!
• 10 questions about Maiasaura; a quiz to print out
• A first-grade level Maiasaura subtraction activity print-out.
• A quiz about Maiasaura - Unscramble the answers and see how much you know about Maiasaura! For grades 2-3.
• A Maiasaura Activity print-out for beginning readers (advanced first graders to second graders). Students read and follow the directions to complete a Maiasaura scene.