Giant dinosaur carcasses: A key food source for Jurassic predators?

A new study led by researchers Cameron Pahl and Luis Ruedas of Portland State University suggests that the massive carcasses of giant dinosaurs might have played a crucial role as food sources for the ferocious carnivorous predators of the Jurassic period.

Consistent source of food

The study explores the idea that carnivorous dinosaurs, which inhabited ecosystems teeming with both living and deceased prey, might have evolved certain traits specifically to exploit the colossal carcasses of sauropods. 

The long-necked sauropods could have been a consistent and abundant source of nourishment for meat-eating dinosaurs.

Virtual ecosystem 

To investigate, the team developed a virtual simulation of a simplified dinosaur ecosystem. This model was based on the ancient fauna of the Jurassic-aged Morrison Formation, which included large predators like Allosaurus alongside large sauropods, their carcasses, and an infinite supply of huntable stegosaurs, noted the researchers.

Within this virtual ecosystem, the carnivores were designed to emulate the behaviors of allosaurs, and possessed specific traits. These traits either enhanced their hunting skills or optimized their scavenging efficiency, aiding them in deriving energy from both living prey and sauropod remains. 

Food acquisition strategies 

The primary goal of the simulation study was to gauge the evolutionary advantage of these carnivores in different food acquisition scenarios.

Remarkably, the model revealed that when faced with an ample supply of sauropod carrion, scavenging presented a more rewarding strategy than hunting. This discovery implies that Jurassic carnivores might have undergone evolutionary adaptations that sharpened their carcass detection and exploitation skills.

Studying a dinosaur carcass

The experts emphasized that this model represents a simplified abstract of a complex system, and that the results might be altered with the inclusion of more variables, such as additional dinosaur species or features of the life history of the simulated dinosaurs. 

The researchers noted that models like this might improve our understanding of how the availability of carrion can influence the evolution of predators.

Dinosaur carcass study implications

“Our evolutionary model demonstrates that large theropods such as Allosaurus could have evolved to subsist on sauropod carrion as their primary resource. Even when huntable prey was available to them, selection pressure favored the scavengers, while the predators suffered from lower fitness,” wrote the study authors. 

“So we think allosaurs probably waited until a bunch of sauropods died in the dry season, feasted on their carcasses, stored the fat in their tails, then waited until the next season to repeat the process.” 

“This makes sense logically too, because a single sauropod carcass had enough calories to sustain 25 or so allosaurs for weeks or even months, and sauropods were often the most abundant dinosaurs in the environment.”

More about Jurassic carnivorous dinosaurs

The Jurassic period, spanning from 200 million to 145 million years ago, is a significant chapter in Earth’s history. During this time, our planet saw the evolution of some of the most awe-inspiring dinosaurs, many of which were carnivorous.

Allosaurus: The apex predator

Among the top-tier predators of the Jurassic was the Allosaurus. These formidable dinosaurs, reaching lengths of up to 39 feet, roamed North America and possibly Europe.

They possessed sharp teeth, powerful jaws, and long, slashing claws, making them formidable hunters. Evidence suggests that Allosaurus might have hunted in packs, taking down even the massive long-necked herbivores of their time.

Ceratosaurus: The horned hunter

Distinguished by its large nasal horn and two smaller horns above its eyes, the Ceratosaurus was a unique carnivore. Residing mainly in North America, these creatures reached lengths of around 20 feet.

Apart from their striking horned appearance, Ceratosaurs also had an elongated, flexible tail, and their jaws bristled with sharp teeth. While they might not have been as dominant as Allosaurus, they still held their own in the Jurassic food chain.

Dilophosaurus: The early Jurassic hunter

Living during the Early Jurassic, the Dilophosaurus is one of the earlier large predators. With a length of about 20 feet, it was smaller than its later Jurassic counterparts. A notable feature was the pair of crests on its skull. While its exact hunting methods remain a subject of debate, some suggest it might have primarily feasted on smaller prey or scavenged carcasses.

Megalosaurus: Europe’s pioneer predator

Megalosaurus was one of the first dinosaurs ever described scientifically. Native to Europe, this predator reached lengths of up to 30 feet. Its strong legs and powerful jaws made it a significant threat to the herbivores of its environment. As an early discovery, Megalosaurus played a crucial role in our understanding of dinosaurs and their place in Earth’s history.

Carnivorous dinosaurs and dinosaur carcasses

Carnivorous dinosaurs, with their diverse sizes and adaptations, played pivotal roles in their ecosystems. They helped balance populations by preying on herbivores, ensuring that no single species could overpopulate and deplete the environment’s resources.

Additionally, as mentioned previously, their interactions with other predators and dinosaur carcasses created a dynamic, interwoven food web. Each species had its unique niche and role.

In summary, the Jurassic period was an age of incredible biodiversity, with carnivorous dinosaurs being some of its most iconic representatives. From the fearsome Allosaurus to the unique Ceratosaurus, these predators dominated their environments, showcasing the vast range of evolutionary adaptations that dinosaurs had achieved. Their legacy, both in fossil records and our cultural memory, serves as a testament to the ever-fascinating story of life on Earth.

The study is published in the journal PLoS ONE.

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