Maiasaura

What it was like

Maiasaura was a duck-billed plant eater with a broad, flat beak and rows of grinding teeth for chewing tough plants. It grew to about 9 meters (30 feet) long and likely moved on two legs or four, depending on its speed.

It is best known for evidence of parental care: nests, eggs, and young at different growth stages found together suggest that Maiasaura fed and protected its hatchlings in the nest rather than leaving them to fend for themselves.

Its world

Maiasaura lived in what is now Montana about 84 to 72 million years ago, during the Late Cretaceous, on a floodplain crossed by rivers and dotted with conifer forests. Its fossils come from the Two Medicine Formation.

It shared its floodplain habitat with the horned Achelousaurus and Einiosaurus, the armored Euoplocephalus, and predators including Daspletosaurus and Troodon.

How it was found

Horner and Makela named Maiasaura in 1979, after finding a nesting site in Montana with eggs, hatchlings, and adults together. Only 5 finds of the genus are formally recorded, but the original nesting site remains one of the most important discoveries in dinosaur research.