Alberta Fossil Marks Suggest Raptor Scavenged on Tyrannosaur Relative

Key points

• The fossil belongs to an immature Albertosaurus, estimated at 8-11 years old, found in Alberta's badlands in 2022.
• Researchers analyzed bite marks on the jawbone, comparing tooth spacing to contemporary carnivores to identify the feeder.
• The marks align with dromaeosaurids (raptors), which were significantly smaller than the Albertosaurus, suggesting scavenging rather than predation.
• No healing signs were present, indicating the marks were made around the time of the dinosaur's death.
• The study was led by master's student Joshua Doyon and supervised by Professor Philip Currie.

Background

This discovery adds to the growing body of evidence regarding complex food webs in the Late Cretaceous. While previous studies have shown dromaeosaurids feeding on herbivores and pterosaurs, this is the first clear evidence of them scavenging on tyrannosaurids. It complements earlier findings of reciprocal feeding interactions between these two groups, helping to reconstruct the ecological dynamics of prehistoric Alberta.

How outlets are covering it

Global News emphasizes the rarity of carnivore-on-carnivore evidence and highlights the possibility of cannibalism by a young Albertosaurus. La Brújula Verde provides a detailed technical breakdown, noting the geometric corrections used to rule out other candidates like troodontids and Richardoestesia, and stresses that the raptor hypothesis is the most supported but not definitive. Yahoo's coverage focuses on the cannibalism angle, suggesting a baby tyrannosaur might have eaten its relative, though it lacks the specific forensic details provided by the other sources.

Why it matters

This finding refines our understanding of prehistoric ecosystems by demonstrating that smaller predators played a role in scavenging large apex predators. It challenges the simplistic view of food chains and highlights the importance of carcass resources in the Late Cretaceous, offering new insights into the behavioral ecology of dinosaurs.

What to watch

Researchers will continue to analyze the fossil for additional clues, though the fragmentary nature of the remains limits further reconstruction. The study may prompt further investigations into other fossil sites to determine if such scavenging behavior was common among dromaeosaurids in the region.