Jurassic jaws: Predatory secrets of carnivorous dinosaurs

A new study led by Roberto Lei from the Università degli Studi di Modena e Reggio Emilia offers new insights into the feeding habits of carnivorous dinosaurs in North America. 

The research, conducted on Jurassic rocks of the USA, was specifically focused on bite marks on the bones of giant sauropods like Diplodocus and Brontosaurus, which were primarily left by theropod dinosaurs.

Dinosaur bones

The study transcends the common belief that tyrannosaurs were the main predators leaving marks on dinosaur bones. Instead, it highlights the role of other large carnivores in the Morrison Formation, a geological formation from the Upper Jurassic period approximately 150 million years ago. 

Remarkably, the research team discovered 68 sauropod bones from this formation bearing distinct bite traces from theropods.

One of the striking findings is the absence of healing in these bite marks, suggesting that the bites were either inflicted in a lethal attack or were a result of post-mortem scavenging. 

Wear patterns

The researchers also found similar wear patterns on the teeth of Morrison Formation theropods to those observed in tyrannosaurs, indicating a more frequent involvement in bone-biting than previously thought.

However, attributing these bite marks to specific theropod species, such as Allosaurus or Ceratosaurus, remains challenging due to the presence of multiple potential predators. 

Study significance 

Dr. David Hone of Queen Mary University of London, the study’s corresponding author, emphasized the significance of these findings.

“This new work helps us understand the ecological relationships between dinosaurs in the Jurassic and reveals that the habits of the larger carnivores then were closer to that of the tyrannosaurs than previously thought. It’s another important step in reconstructing the behavior of these ancient animals,” said Dr. Hone.

The focus on bite and tooth marks has unveiled intriguing aspects of the lives of dinosaurs, shedding light on the interactions among some of the largest animals to have ever existed on Earth.

Carnivorous dinosaurs 

Carnivorous dinosaurs, known scientifically as theropods, were a diverse group of meat-eating dinosaurs that lived during the Mesozoic Era. Here are some key aspects:

Diverse sizes and habitats

Theropods ranged in size from small, bird-like creatures to massive predators like Tyrannosaurus rex. They inhabited various environments across the globe, adapting to different ecological niches.

Distinctive features

Most carnivorous dinosaurs were bipedal, meaning they walked on two legs. They typically had strong hind legs, sharp claws, and powerful jaws filled with serrated teeth designed for slicing flesh.

Feeding and hunting

While primarily carnivorous, some theropods may have been omnivores or even scavengers. Their hunting strategies likely varied, with some possibly hunting in packs, while others were solitary predators.

Evolutionary significance

Theropods are particularly important in the study of dinosaur evolution, as they are the ancestors of modern birds. The discovery of feathered theropods has been crucial in understanding this evolutionary link.

Famous examples

Apart from the well-known T. rex, other famous theropods include Velociraptor, known for its speed and agility, and Spinosaurus, which is believed to have been semi-aquatic.

Intelligence and behavior

Some theropods, like the Troodon, are believed to have been among the most intelligent dinosaurs. Evidence suggests that certain theropods may have had complex social behaviors, although much of this remains speculative.

Fossil discoveries

Fossilized remains of theropods have been found on every continent, including Antarctica. These fossils range from complete skeletons to isolated bones and footprints, providing valuable insights into their physiology and behavior.

Cultural impact

Carnivorous dinosaurs have captured the public imagination in movies, books, and other media. Their fierce reputation and dramatic appearances make them some of the most popular dinosaurs in pop culture.

Theropods offer insights into the prehistoric past, as well as the evolutionary processes that have shaped life on Earth, including the origins of birds.

The study is published in the journal PeerJ Life & Environment. 

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