Dinosaur teeth reveal secrets to Earth's past, UT study finds
The video at the top of this story is coverage from Aug. 5, 2025, about dinosaur tracks that may have been uncovered by floods in Central Texas.
AUSTIN (KXAN) — Ancient titans once roamed the Earth, consuming plants and animals in order to survive. A new study from the University of Texas is helping paint a picture of ancient life by looking at tiny particles hidden in dinosaur teeth.
“Dinosaur teeth are really special, because dinosaurs would replace their teeth throughout their lives, kind of like a shark or a modern day crocodile,” said Liam Norris, Ph.D., a paleontologist at the Texas Science and Natural History Museum.
While attending UT Austin’s Jackson School of Geosciences, Norris conducted research on five sets of dinosaur teeth.
The fossils, collected at the Carnegie Quarry at Dinosaur National Monument in Utah, all came from the late Jurassic period.
The teeth belonged to the long necked herbivores Diplodocus and Camarasaurus, the Camptosaurus, and the meat-eating Allosaurus and Eutretauranosuchus.
“When we eat food, the calcium in that food is incorporated into our skeleton,” Norris said. “You can figure out which plant eaters are eating which plants, and which meat eaters are eating which plant eaters.”
Norris looked at the density of calcium isotopes and connected them with samples from fossilized plants.
Norris’ research, published in Palaeogeography, Palaeoclimatology, Palaeoecology, reveals not just what the dinosaurs eat, but how.
“Diplodocus was likely eating a little bit on the ground as it walked along, but then also it probably brought its head up and ate in the trees as well,” Norris said.
The teeth from the Camarasaurus, hard and strong, showed that it ate higher up in the canopy. It likely consumed twigs and bark. While the Camptosaurus lived closer to the ground and ate soft vegetation.
The animals all traveled together in herds. With the new study, it reveals how they were able to do so while not consuming the same food. They each essentially targeted different plants in the same area.
Previously, scientists believed each targeted different levels of the canopy. This study reveals they did that but also have preferred plants in those canopies.
The Allosauraus, the most common carnivore in the area at the time, also revealed something interesting. It, of course, ate the herbivores at the time but didn’t eat bone.
“Allosaurus was probably coming up to these animals and just tearing the flesh off the bone,” Norris said.
The Eutretauranosuchus, basically a giant crocodile, likely ate fish. Though there were fewer samples of this species for Norris to test.
In all, Norris studied teeth from 17 individual animals across the five species.
“Dinosaurs could not chew. They couldn’t move their jaw side to side, so they would actually swallow their food whole. It would go into what’s called a gizzard, which is a organ that chickens have,” he said.
For Norris, the work helps color in the margins of what ancient life once looked like.
“There’s, I don’t know, an assumption that Paleontology is done and that we’ve found everything,” Norris said. “In a way, this research has added to the story of evolution, and thus our origin story.”
