Dino-Data Card # 1

Through the work of Jack Horner and other scientists, it has been learned that several different dinosaurs lived at the same time (roughly 80 million years ago) in Montana. Three of these dinosaurs were Orodromeus (mountain runner), a swift plant eater; Troödon (wounding teeth), a small but fierce predator (carnivore); and Maiasaura (good mother lizard), a larger herbivore. There is good fossil evidence to show that all three laid eggs in nests. The nesting sites included two islands surrounded by a shallow alkaline lake.

The environment at that time included volcanoes and a few mountains to the west (not the Rockies, as they were in the process of uplifting) and to the east, a warm interior seaway, which divided North America from north to south.


Dino-Data Card # 2

  1. Maiasaurs were herbivorous. They weighed roughly 3 to 4 tons as adults. They probably ate 200 lb. of food each day.
  2. Many Maiasaur nests have been found at two sites, Egg Mountain and Egg Island. At the time of the dinosaurs, each of these sites was an island. Although islands are rather limiting in space, the nests were usually found 20 to 30 feet apart.
  3. The sharp serrated teeth of a small dinosaur called Troödon have been found in the nesting area of Maiasaurs.
  4. Large numbers of bones in some areas of Montana indicate that there existed a herd of Maiasaurs of nearly 10,000 individuals. These individuals varied in size from 9 to 25 feet in length.