The largest dinosaur population growth study in history has revealed a detailed account of how the "good mother lizard," Maiasaura peeblesorum, lived and died.
The findings provide the most detailed life history of a dinosaur known to science, and it could provide insight into the lives of other dinosaur species, Montana State University reported.
"This is a dramatic step forward from studying fossilized creatures as single individuals to understanding their life cycle. We are moving away from the novelty of a single instance to looking at a population of dinosaurs in the same way we look at populations of animals today," said Jack Horner, curator of the Museum of the Rockies at MSU.
To make their findings, a team of researchers looked at the fossil bone microstructure (histology) of 50 Maiasaura tibiae. These studies reveal all aspects of dinosaur growth as well as metabolism and age at death.
Histology is the key to understanding the growth dynamics of extinct animals," said study leader Holly Woodward. "You can only learn so much from a bone by looking at its shape. But the entire growth history of the animal is recorded within the bone."
The findings reveal the dinosaur had bird-like growth rates throughout the majority of its life, but its bone tissue closely resembled what is seen in modern-day large warm-blooded animals such as elk. Sexual maturity appeared to occur in the third year of life, and the dinosaur reached a weight of about 2.3 tons by the age of eight. If the dinosaurs survived their childhood, they had a window of peak reproductive and physical fitness lasting about six years.
"By looking within the bones, and by synthesizing what previous studies revealed, we now know more about the life history of Maiasaura than any other dinosaur and have the sample size to back up our conclusions," Woodward said. "Our study makes Maiasaura a model organism to which other dinosaur population biology studies will be compared."
Maiasaura were social dinosaurs that nested in colonies. They walked on two legs during the early years of life and later moved onto four. They has a strange diet consisting of staples such as rotting wood. The findings mark the beginning of The Maiasaura Life History Project, which aims to discover as much as the life of the "good mother lizard" as possible.
The findings were published in a recent edition of the journal Paleobiology.
