Maiasaura (from the Greek "μαία" and the feminine form of Latin saurus, meaning "good mother reptile") is a large herbivorous hadrosaurid ("duck-billed") dinosaur genusthat lived in the area currently covered by the state of Montana in the Upper Cretaceous Period (mid to late Campanian), about 76.7 million years ago. lived in North America about 75 million years ago, probably the direct ancestor of the Hadrosaur Edmontosaurus. It was named by Jack Horner and Robert Makela in 1979. The first fossils of Maiasaura were discovered in 1978. In 1979. the genus was named. The name refers to the find of nests with eggs, embryos and young animals, in a nesting colony. Astronaut Loren Acton took a bone fragment and eggshell piece of a Maiasaura on an 8-day Spacelab 2 mission in 1985—the first dinosaur in space. These showed that Maiasaura fed her young while they were in the nest, the first time such evidence was obtained for a dinosaur. Hundreds of bones of Maiasaura have been dug up.
Maiasaura was about nine metres long. Young animals walked on their hind legs, adults on all fours. Maiasaura was probably closely related to Brachylophosaurus.
Maiasaura was cloned by InGen and Maiasaura lived on Isla Sorna in the east.
It is unknown if any Maiasaura were cloned for Jurassic World.