Fossil of Young Tyrannosaur Reveals Dietary Shifts During Growth

The preserved last meals in the stomach of a juvenile Gorgosaurus provide first direct evidence of dietary changes as tyrannosaurs matured.

An incredible fossil of a young Gorgosaurus, a type of tyrannosaurid, was discovered in Alberta, Canada, with its last two meals still preserved in its stomach cavity.
The meals consisted of the hind legs of two small, birdlike dinosaurs (Citipes elegans), indicating that juvenile tyrannosaurs had a different diet from their adult counterparts.
The different levels of digestion on the bone surfaces suggest the meals were consumed hours or days apart.
This discovery provides hard evidence for the long-held hypothesis that tyrannosaurs adapted to hunt and eat different types of prey during different stages of their lives.
The fossilized juvenile Gorgosaurus was 5 to 7 years old, stood about human height at the hips, and stretched some 13 feet long.