Allosaurus, a large predatory dinosaur, roamed the Earth during the Late Jurassic period (155 to 145 million years ago). This bipedal carnivore was a dominant figure in its prehistoric ecosystem. Understanding its diet and hunting strategies provides insight into ancient food webs.
The Allosaurus Diet: Primary Prey
As an obligate carnivore, Allosaurus primarily ate meat, occupying the apex predator position. Its diet included large herbivorous dinosaurs like Diplodocus, Apatosaurus, Camarasaurus, and Stegosaurus.
Preying on such colossal animals was challenging, so Allosaurus likely focused on vulnerable individuals: the young, old, sick, or injured. While “flesh grazing” on living sauropods is suggested, direct predation on healthy adults by a solitary Allosaurus is debated due to their immense size.
Uncovering the Allosaurus’s Menu: The Evidence
Fossil evidence reveals the dietary habits of Allosaurus. Direct evidence includes bite marks on sauropod and stegosaur bones. For instance, a Stegosaurus tail vertebra shows a puncture wound consistent with an Allosaurus tail spike, and an Allosaurus tail vertebra exhibits a healed wound from a Stegosaurus spike, indicating direct combat.
The morphology of Allosaurus teeth and jaw structure also provides clues. Its sharp, serrated teeth were continually shed and replaced, well-suited for tearing flesh. Though its bite force was weaker than some later large theropods, its robust skull withstood significant vertical forces, suggesting a tearing or slashing feeding style. D-shaped front teeth were likely for puncturing. Stress fractures and injuries on Allosaurus bones also support an active predatory lifestyle, rather than solely scavenging.
Hunting Behavior and Feeding Habits
Allosaurus likely employed ambush tactics, utilizing its speed and agility to surprise its prey. The question of whether Allosaurus hunted in packs remains a subject of ongoing scientific discussion. While some bonebed discoveries, such as the Cleveland-Lloyd Quarry with numerous Allosaurus individuals, have been interpreted as evidence of cooperative hunting, others suggest these congregations resulted from individuals gathering around large carcasses, possibly leading to aggressive interactions among them.
A notable hypothesis, known as the “hatchet-attack” theory, suggests Allosaurus used its skull like a bladed weapon. Despite a comparatively weaker bite, its strong neck muscles and skull structure would have allowed it to deliver forceful downward strikes, inflicting massive wounds on prey. This strategy involved opening its jaws widely and slamming the upper jaw into its victim, effectively slashing and tearing flesh.
Beyond active hunting, Allosaurus likely engaged in scavenging, feeding on carrion when opportunities arose. Some recent research even proposes that Allosaurus might have been a predominant scavenger, similar to modern-day vultures, particularly benefiting from the abundant carcasses of large sauropods. Fossil evidence also points to instances of cannibalism among Allosaurus, suggesting that during times of food scarcity, they may have fed on their own kind.