A 75 million-year-old fossilized dinosaur’s stomach contained its last meal, which was remarkably well-preserved and provided information about its diet.
Researchers at the University of Calgary have discovered that the hind legs of small dinosaurs that resembled birds were discovered within the stomach of the juvenile tyrannosaur Gorgosaurus libratus.
Among the most fearsome carnivores of their era were the tyrannosaurs, which included the more well-known Tyrannosaurus and the Gorgosaurus. Researchers found evidence that indicates ancient tyrannosaurs usually consumed huge herbivores.
However, new study published in the journal Science Advances indicates that the species’ diets evolved as they developed.
According to study co-author Darla Zelenitsky, “this is the first time that such well-preserved stomach contents have been found inside the skeleton of a large species of tyrannosaur.”
The creature was thought to have died at an early age, between five and seven years old, weighing over 700 pounds, or only 10% of an adult’s bulk. 2009 saw the discovery of the fossil in Canada’s Dinosaur Provincial Park.
Toe bones were initially discovered in the dinosaur’s stomach by museum personnel.
Scientists discovered that they were the bones of little dinosaurs called Citipes, around the size of turkeys.
“To reveal what was hidden within, the rock that was inside the rib cage was removed. As coauthor of the study François Therrien noted, “Lo and behold, the entire hind legs of two baby dinosaurs, both under a year old, were present in its stomach.”
Because of the varying stages of digestion, it seemed as though two distinct sets of legs were consumed at various times.
Given that the hind legs would have been the meatiest part of the body, experts speculate that the dinosaur may have deliberately chosen to consume them.
“It’s well-known that tyrannosaurs changed a lot during growth, from slender forms to these robust, bone-crushing dinosaurs, and we know that this change was related to feeding behavior,” Zelenitsky stated.
“They appear to have gone from hunting prey like Citipes – a small fraction of their size – as teenagers to hunting megaherbivore dinosaurs – as large, or larger, than their size – as adults,” she stated.
The finding demonstrates that adult tyrannosaurs could consume considerably larger prey due to their huge heads and powerful teeth, but juvenile tyrannosaurs, with their narrow skulls and blade-like teeth, were better adapted to devour smaller species.