FIELD NOTES
Date: Cretaceous Period
Site: North America
Subject: Hadrosaur
Participants: C. Monroe
Hadrosaurs, commonly known as “duck-billed” dinosaurs, lived on Earth during the late Cretaceous period, 75-65 million years ago. The term Hadrosaur is actually a broad category that contains many species that share common traits, including their distinctive duck-like mouths. Different hadrosaur species could grow to be different sizes. For example, the species sauropholus could be 30 feet long and weigh 2 tons, but the species shantungosaurus could grow to be 50 feet long and weigh 15 tons! That’s almost ten times as large as an elephant!
Because Hadrosaur fossils are often found in large groups, scientists think many Hadrosaur species traveled in herds. Fossils have also been found that show adults standing near eggs, nests, and baby dinosaurs. Based on this evidence, scientists believe that Hadrosaurs looked after and cared for their young. One Hadrosaur species was even given the name maiasaura, or “good mother lizard.”
Some Hadrosaur species had long crests on the backs of their heads. These crests contained passages that connected to the dinosaur’s nasal cavity. Scientists have shown that if air is forced through these passages, the crest can make a loud sound. They believe Hadrosaurs might have used the noises from their crests to communicate with other animals in their herd.
Hadrosaur fossils have been found all over the world. In fact, so many Hadrosaur fossils have been found that scientists believe Hadrosaurs may have been the most populous dinosaur of the late Cretaceous!
Marginal comment: These “duck-billed” dinosaurs actually had hundreds of teeth. Some species could have up to 1,000!
Want to learn more? Check out these sources!
https://www.fossilera.com/pages/about-hadrosaurs
https://www.thoughtco.com/hadrosaurs-the-duck-billed-dinosaurs-1093749