Alberta, Canada
A 75-million-year-old fossilised tyrannosaur has shed light on intriguing diet patterns of the ancient predators as they grew. The fossil had remains of two baby dinosaurs inside it, revealing that the tyrannosaur feasted on them right before it died.
The tyrannosaur was likely around 7 years old—a teenager in dinosaur years—and consumed the hind legs of the baby dinosaurs that were less than a year old.
The bird-like baby dinosaurs, called citipes, are believed to be close cousins of the tyrannosaurus rex.
The study, published in the journal Science Advances, reveals that while young tyrannosaurs preyed on small, young dinosaurs, the adults attacked and ate very large plant-eating dinosaurs, which lived in herds.
The discovery is “solid evidence that tyrannosaurs drastically changed their diet as they grew up,” Dr Darla Zelenitsky, one of the lead scientists in the study, was quoted as saying by BBC.
She said: “We now know that these teenage (tyrannosaurs) hunted small, young dinosaurs.
Also read: Dinosaurs might be roaming some other planet, new study finds
“These smaller, immature tyrannosaurs were probably not ready to jump into a group of horned dinosaurs, where the adults weighed thousands of kilograms.”
The discovery reveals that juvenile tyrannosaurs had narrow skulls and blade-like teeth, and thus were better suited to eat small prey, while adult tyrannosaurs' large skulls and strong teeth enabled them to prey on much larger, heavier beasts.
Watch: New dinosaur species found in Mexico
The fossil of the tyrannosaur was originally discovered in 2009 in Canada’s Alberta; however, it took scientists more than a decade to prepare it for study.
The initial discovery was made by the staff at Alberta’s Royal Tyrrell Museum of Palaeontology, who spotted small toe bones protruding from the rib cage.
Dr Francois Therrien, the other lead scientist in the study, was quoted by BBC as saying, “The rock within the ribcage was removed to expose what was hidden inside. And lo and behold – the complete hind legs of two baby dinosaurs, both under a year old.”
(With inputs from agencies)