You are what you eat, even if your last meal was 150 million years ago! New research reveals that clues about dinosaurs' diets are embedded in their fossilized teeth, where their ancient tooth enamel has preserved secrets of their favorite foods.

Researchers from The University of Texas at Austin have uncovered fascinating details about the dietary habits of various dinosaur species, showing that they were quite selective eaters. This could explain how numerous massive creatures thrived together in the same ecosystem.

Lead researcher Liam Norris explains that the calcium isotopes in tooth enamel reflect distinct chemical signatures found in different plants and parts of trees. This study sheds light on a previously puzzling question: how giant herbivores coexisted in the same area.

Norris examined teeth from four dinosaur species and a crocodyliform—both herbivorous and carnivorous—that inhabited the Western U.S. during the Late Jurassic period. The plant-eaters included the long-necked Camarasaurus, the short-armed Camptosaurus, and the heavy-legged Diplodocus, while the meat-eaters consisted of bipedal Allosaurus and the smaller Eutretauranosuchus. Their fossils were beautifully preserved in the Carnegie Quarry in Utah, a site formed during a severe drought.

"Studying the fossils from a single deposit allowed us to uncover incredible insights about these dinosaurs living side by side," said Rowan Martindale, an associate professor at the Jackson School.

Norris analyzed enamel from 17 individual fossils and determined dietary preferences that go beyond just choosing different heights of vegetation. For instance, the Camptosaurus favored soft leaves and buds, while the Camarasaurus preferred hardy conifers.

This research suggests that the dinosaurs didn't just eat at different levels; they also targeted specific parts of plants. The findings further support the idea that long-necked dinosaurs evolved flexible necks to efficiently reach food without straining their massive bodies.

While the Allosaurus and Eutretauranosuchus exhibited some overlap in diet, it's likely that they targeted different foods; the Eutretauranosuchus may have preferred fish, whereas the Allosaurus primarily dined on herbivorous dinosaurs.

These insights provide a richer understanding of the lush vegetation and productivity of the era, affirming that this prehistoric ecosystem was as vibrant as we once imagined.

Co-author Henry Fricke of Colorado College added to the discussion, emphasizing the significance of their findings.