Everything we know about dinosaurs, we’ve learned from fossils. Over the years, new technological advancements have allowed for more careful examination of available fossils, giving new insights into dinosaur anatomy. Plus, researchers have often extrapolated from know facts about extant animals to guess what dinosaurs were like (earlier this year, for example, researchers estimated the walking speed of T-rex).
Due to limitations in what can be known from fossils and through extrapolation, we know next to nothing about the behavior of dinosaurs. However, a set of recently discovered fossils has provided a rare glimpse into the social lives of one dinosaur – the herbivore Mussaurus patagonicus.
The fossils were discovered from a sag basin in southern Patagonia (Argentina) and feature 80 individuals representing various life stages – embryos to adult individuals, and nests with whole clutches of eggs. According to researchers, the occurrence of adults, sub-adults, juveniles and infants within a square kilometer radius suggests that the dinosaur “maintained social cohesion throughout the different stages of their lifespan”.
“Field observations and X-ray computed tomography imaging of five complete nests confirms that eggs were arranged in two or three layers within elongate depressions or trenches with an irregular bottom profile.”
Researchers also found evidence for individuals having formed age-based subgroups within the community. Age segregation is a feature in many extant animals with large body size difference between juveniles and adult. In the Mussaurus, hatchlings weight 0.1 kg while adults weigh up to 1500 kg. Grouping up with individuals of the same body size allows animals to better synchronize grazing and other behaviors.
After examining them, researchers have dated the fossils to 192 million years ago. Researchers now think that the social cohesion of the Mussaurus may have contributed to their eventual success in survival and expansion. Read more about the study by Diego Pol, Adriana Mancuso, Roger Smith, Claudia Marsicano, Jahandar Ramezani, Ignacio Cerda, Alejandro Otero & Vincent Fernandez here.
