Researchers from the Royal Tyrrell Museum of Paleontology in Alberta have, for the first time, identified a tyrannosaurid dinosaur fossil that contains the bones of its last meal still inside the ribcage area. This remarkable find offers a direct glimpse into the dietary habits of ancient predators and how their eating choices evolved as they grew. The study appears in Science Advances, a leading scientific journal known for publishing rigorous, peer reviewed work in the field of paleontology and related sciences.
The fossil in question is a Gorgosaurus, a close cousin of the more famous Tyrannosaurus rex. It was uncovered east of Calgary, Canada, and has been dated to approximately 75 million years ago. When scientists conducted a careful lab examination, they discovered remnants from two individuals belonging to the chitipati, a bird like dinosaur, preserved among the bones of the predator. This direct evidence shows that the animal’s last meal consisted of flight capable, small to medium sized prey rather than a full meal from a larger, more diverse prey set.
Paleontologists have noted that Gorgosaurus, like other tyrannosaurids, displayed selective feeding habits at different life stages. The specimen suggests that younger individuals targeted quick and nimble prey such as chitipati. As these dinosaurs aged and grew larger, reaching lengths near 10 meters and weights exceeding three tons, their dietary strategy appears to have shifted. Rather than pursuing small game exclusively, these giants transition into feeding patterns associated with larger vertebrate prey, reflecting changes in jaw strength, bite force, and overall physiology that accompany growth. This observation aligns with broader patterns seen in other large predators, where the diet becomes broader as the animal matures and its ecological role changes within its environment.
Francois Therrien, the lead author of the study, comments that large dietary shifts are not rare in nature. He notes parallels with modern predators like crocodilians and Komodo dragons, which respectively move from early insect consumption to rodents and then to larger prey as they mature. This continuum helps explain how growth, energy needs, and prey availability shape feeding behavior over an animal’s life history, from juvenile stages to adulthood. The discovery from Alberta provides a vivid snapshot of that process in a late Cretaceous tyrannosaurid, enriching our understanding of how these iconic predators fit into their ancient ecosystems and how their predatory strategies evolved through time.
Scholars also reflect on the broader implications for the fossil record and ancient food webs. The presence of prey remains within the skeleton of a tyrannosaurid demonstrates that predation events could be tightly intertwined with the predator’s development, influencing growth rates, hunting methods, and ecological interactions. These findings encourage a more nuanced view of tyrannosaurid life histories and invite further research into how widely such intra dietary evidence occurs across other species from the period. The Alberta discovery thus stands as a compelling data point in the ongoing effort to reconstruct ancient ecosystems with greater precision and detail, offering Canadians and Americans alike a clearer picture of how top predators shaped and were shaped by their world. In this sense, the study contributes a meaningful chapter to the story of dinosaurs and their complex, evolving diets. (Science Advances)