Allosaurus, the giant Jurassic dinosaur, was a scavenger and not a predator as previously thought, according to a new study that could “overturn 150 years of established thinking.”
Measuring up to 40 feet tall, the beast probably got most of its calories by sweeping the carcasses of huge four-legged, long-necked herbivorous dinosaurs called sauropods that lived there.
Given the huge supply of rotting sauropod meat, Allosaurus was not under any pressure to dominate the prey and may have evolved to become a “terrestrial vulture.”
According to the study’s authors, the Allosaurus did not develop powerful bite forces or “advanced cursor adaptations,” that is, limbs adapted to run to catch prey.
They also lacked binocular vision, known as stereopsis: the perception of depth produced by the brain when it receives visual stimuli from both eyes in combination.
Allosaurus (pictured), which was a massive carnivore, rivaling the stature of T. rex, but its eating habits were quite different from the famous T. rex, according to the new study
The study was conducted by Cameron Pahl and Luis Ruedas, researchers at Portland State University in Oregon, who claim to be raising a century and a half of established thought about gender.
“Allosaurus and relatives have been considered apex predators for over 100 years, but our model shows that it is possible that these dinosaurs evolved to fill a different niche,” they said in their paper.
Carrion [dead flesh] generated by their sauropod-sized whale-sized neighbors may have been abundant enough to support them as forced scavengers.
Experts suggest that dinosaurs with limited access to dead meat lying on the ground evolved into vicious predators, such as T. rex.
These predators had to aggressively hunt scary prey to try to stay alive.
“The absence of sauropods in certain environments led to more obvious predatory adaptations in theropods such as tyrannosaurs, which evolved without access to a significant carrion of sauropods,” the researchers explained.
“It may have forced them to meet their hunting energy budgets and pressured them to evolve differently.”
Allosaurus is a type of dinosaur dating from the late Jurassic period (between 155 and 145 million years ago), which lived mainly in present-day North America.
Remains of Allosaurus have been found in the Morrison Formation, a series of sedimentary rocks that extend into the western United States, which is a fossil hunting refuge for researchers.
Like the famous T. rex, allosaurs were theropods: a clade of dinosaurs characterized by hollow bones and three-toed limbs that walked on two legs.
The Allosaurus had dozens of sharp, serrated teeth and arms with long claws, longer than those of a T-rex. It lived between 155.7 and 150.8 million years ago at the end of the Jurassic
Remains of allosaurs have been found in the Morrison Formation (pictured), a series of sedimentary rocks that extend into the western United States, which is a fossil hunting refuge for researchers.
Allosaurs were the largest meat-eating dinosaurs of their time and location, reaching 32 feet and weighing up to 2.5 tons (with some estimates up to 4 tons).
They also had a large head, as well as jaws that were filled with long, sharp, jagged teeth that could be easily thrown and replaced continuously. Also like T. rex, they had small arms and hands.
Together, these “superficial similarities” with T. rex led to Allosaurus being considered the main predator of the Morrison Formation.
To learn more about whether this was true, the authors used a computer model that simulated the relationship between the channels present in the Morrison formation generated by the death of sauropods and the energy requirements of allosaurs.
The sauropod dinosaurs (pictured) walked on all fours and had a long, distinctive neck. They were widespread: their remains have been found on all continents except Antarctica. This new study suggests that his remains kept the Allosaurus alive
They also examined the morphological attributes of the skull, including the extent of binocular vision in predators versus scavengers, as well as ecological fossil data such as the relative population of predators, herbivores, and scavengers.
The relative fragility of the skull and dentition of Allosaurus had already cast doubt on Allosaurus being a predator.
But in addition to this deficit, Allosaurus did not have the binocular vision (stereopsis) needed to be a successful predator, the team claims.
Experts estimate that the binocular vision of the Allosaurus was only 30% that of T. rex and 15% that of the modern lion.
Allosaurs were contemporary in time and space, with some of the largest herbivorous dinosaurs ever recorded.
These would have included dinosaurs known as Camarasaurus, Barosaurus, Apatosaurus, Diplodocus, Brontosaurus, Supersaurus and Brachiosaurus.
The brachiosaurus, in particular, was considered the largest terrestrial animal it has ever lived and could weigh up to 70 feet long and weigh 64 tons.
Meanwhile, the Supersaurus measured more than 110 feet and weighed up to 40 tons.
Paleontologist James Madsen Jr. assembles a skeleton composed of Allosaurus from the Cleveland-Lloyd Dinosaur Quarry
If these giant dinosaurs died primarily of natural causes, such as disease, starvation, and depletion, as is typical of many modern herbivorous populations, their carcasses would have been abundant enough to keep Allosaurus even without them taking on any predatory behavior. , concludes the team.
These new findings appear to run counter to the results of a study published last year by leading paleontologists, who named a new species of Allosaurus: Allosaurus jimmadseni.
A. jimmadseni reduced his prey to death in food hunting, according to the study, and had longer weapons than the T.rex, making him an even better hunter.
The study has been published in Ecological Modeling.