For many years, dinosaurs, particularly the Tyrannosaurus rex, have fascinated both the public and scientists. Often portrayed in popular culture as a dominant and terrifying predator, the T. rex has been the subject of much debate among paleontologists. While traditionally seen as an apex hunter, recent studies suggest that the T. rex also scavenged, feeding on the remains of dead animals, much like some modern predators.
What did the T. rex eat, and how did it capture its prey? Investigations into fossils found alongside T. rex remains indicate that herbivorous dinosaurs like the horned Triceratops and the duck-billed Edmontosaurus were likely part of its diet. Evidence for this includes the presence of T. rex bite marks on the bones of these dinosaurs.
Still, uncovering the specifics of T. rex hunting and feeding behaviors is challenging and often requires detailed analysis of fossils. Sometimes, fossilized footprints or marks on bones can offer insights into how these creatures interacted with each other and their environment.
Despite these efforts, many questions remain about the hunting tactics of T. rex. In a study conducted by paleontologist John Scannella and myself, we examined a nearly complete Edmontosaurus skull, hoping to shed light on this topic.
Bite marks on a skull
At the Museum of the Rockies in Bozeman, Montana, a nearly complete Edmontosaurus skull is on display, offering a rare insight into the feeding behavior of the T. rex. Discovered in 2005 in eastern Montana on federal land, this skull shows significant evidence of a T. rex attack.
A partial tooth tip penetrates the snout of the Edmontosaurus, with numerous bite marks visible on both sides of the skull. The deep penetration suggests a powerful bite, and the absence of healing indicates the tooth was likely embedded either shortly before or after the Edmontosaurus died.
CT scans provide a clear view of the tooth’s position within the skull, suggesting it broke during a face-to-face encounter. Such interactions in modern animals typically result in the death of the victim, and given the circumstances, it is unlikely that the Edmontosaurus survived the attack.
Who bit this Edmontosaurus?
Identifying the predator responsible for bite marks can be challenging, as the marks often lack unique details. However, carnivorous dinosaur teeth can be more distinctive. By comparing the shape and size of the embedded tooth’s serrations with those of various carnivorous dinosaurs from the same era, we identified the attacker as a Tyrannosaurus.
Determining the size of the Tyrannosaurus involved required comparing the serrations on the tooth with those on teeth in other Tyrannosaurus skulls. Our findings suggested that the tooth belonged to an adult Tyrannosaurus with a skull approximately one meter in length.
What do these bite marks tell us?
The bite marks on the Edmontosaurus skull indicate that, beyond being killed by the Tyrannosaurus, it was also consumed. The location of the bite marks on the right side of the skull, behind the eye, and on the left side along the bottom jaw, suggests targeted consumption of the fleshier parts of the skull.
In duck-billed dinosaurs like the Edmontosaurus, the most substantial chewing muscles reside in the rear third of the skull, an area rich in flesh after other soft tissues had been consumed. Modern carnivores tend to eat the fleshier parts of a carcass, such as the limbs and organs, before moving to less meaty parts like the skull.
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Given that only the skull remains, it appears the Tyrannosaurus removed most flesh from the Edmontosaurus before the carcass was washed away and buried. Having direct fossil evidence of a dinosaur being killed and eaten by a Tyrannosaurus is exceedingly rare, offering valuable insights into the predatory behaviors of large carnivorous dinosaurs.
Taia Wyenberg-Henzler, PhD Candidate, Paleontology, University of Alberta
This article is republished from The Conversation under a Creative Commons license. Read the original article.
