Maiasaura was a large, herbivorous dinosaur that lived during the Late Cretaceous period, around 76 to 80 million years ago. It was known for its distinctive duck-bill shape and could grow up to 30 feet long. Fossils of Maiasaura have been found primarily in North America, particularly in what is now Montana. This dinosaur is notable for its nesting behavior, as evidence suggests it cared for its young. Fossilized nests containing eggs and juvenile Maiasaura have provided insights into their social structure and parenting habits, making them one of the first dinosaurs known to exhibit such behaviors.