An analysis of wear on the fossilized teeth of the hadrosaurian dinosaur Maiasaura peeblesorum indicates their juveniles may have eaten softer, more nutritious food than adults, hinting at advanced parental care among dinosaurs.
An artist’s reconstruction of adult Maiasaura and young. Image credit: Brian Regal.
Maiasaura peeblesorum is a duck-billed dinosaur species that roamed our planet about 75 to 80 million years ago (Late Cretaceous epoch).
First discovered in Montana, these large, herbivorous dinosaurs lived in herds and were thought to have been highly social creatures, especially in contrast to those that may have had different reproductive strategies.
Extensive fossil findings of preserved Maiasaura peeblesorum nests have since made them a key species for understanding the reproductive behaviors and ecology of many other types of duck-billed dinosaurs.
In the new study, Ohio State University’s Dr. John Hunter and Dr. Christine Janis from the University of Bristol and Brown University found that the teeth of juvenile Maiasaura peeblesorum showed significantly more crushing wear, while adults exhibited more shearing wear, suggesting parents could have been bringing softer, higher-protein food to their children than they themselves ate.
“Today, this behavior is typical of birds whose young are confined to the nest for a time after hatching,” Dr. Hunter said.
“The urge for a bird to feed a youngster is a very old behavior.”
“What we’re providing is that evidence for that behavior probably goes much further than the origin of birds, perhaps to the origin of dinosaurs.”
Juvenile Maiasaura peeblesorum likely ate more nutritious low-fiber foods like fruit while their caretakers consumed a greater proportion of tougher, nutritionally poor high-fiber plant parts.
In mammals today, the same patterns of shearing wear would likely be present in grazers like horses, antelopes and cows, while low-fiber diet eaters like tapirs would have dental patterns similar to the young dinosaurs.
In comparing the types of wear on dinosaur teeth, the researchers also suggested that shifts in diet may have also performed an important role in early growth and development.
In this instance, their results show that the diet of juvenile Maiasaura peeblesorum may have caused them to grow particularly fast in their first year.
The scientists also consider other interpretations of their results. Instead of consuming completely different fare, dinosaur parents could have been feeding their young partially regurgitated food, yet another behavior now common in birds.
Alternatively, juveniles could also have left the nest to forage for themselves, an activity now seen in modern herbivorous lizards.
“While that solution is less likely as juveniles were helpless, and probably dependent on their parents to feed them during the first weeks after hatching, learning more about their remains can widen scientists’ perspectives of what sophisticated biological and social systems dinosaurs may have had,” Dr. Hunter said.
“The further back in time you go, the less of a fossil record you have, so paleontologists have to draw from different sources of inspiration from different parts of the living.”
“So even among closely related dinosaurs, there is probably still quite a bit to learn about them.”
“If possible, future studies could examine other fossils of the very youngest dinosaurs for dental microwear to test other hypotheses regarding dinosaur embryos and hatchlings.”
The team’s findings appear in the journal Palaeogeography, Palaeoclimatology, Palaeoecology.
_____
John P. Hunter & Christine M. Janis. 2026. Tooth wear in juvenile and adult hadrosaurs: implications for parental care in Maiasaura. Palaeogeography, Palaeoclimatology, Palaeoecology 690: 113707; doi: 10.1016/j.palaeo.2026.113707
