Acrocanthosaurus was a formidable bipedal theropod dinosaur that roamed North America during the Early Cretaceous period, approximately 125 to 100 million years ago. Its name, meaning “high-spined lizard,” refers to the distinctive tall neural spines along its back. This massive carnivore’s physical characteristics offer insights into its predatory lifestyle.
Physical Adaptations for Predation
The physical attributes of Acrocanthosaurus were well-suited for predation. Its skull, which could reach up to 4.2 feet in length, was long, low, and narrow, housing powerful jaws. These jaws contained numerous curved, serrated, blade-like teeth, with around 38 in the upper jaw and potentially up to 30 in the lower. Studies suggest Acrocanthosaurus possessed a powerful slicing bite, with an estimated bite force of up to 16,894 Newtons at the rear of its jaws.
Beyond its formidable bite, Acrocanthosaurus also utilized its robust forelimbs in predation. Each hand bore three clawed digits, with the first two claws likely being permanently flexed. While its forelimbs could not swing far forward for initial capture, they were capable of strong retraction. This allowed Acrocanthosaurus to hold struggling prey tightly, impaling it further with its claws.
Its large size, reaching up to 38 feet and weighing 4.4 to 8.4 metric tons, combined with a muscular build, allowed it to tackle large animals. The distinctive high neural spines along its neck, back, and hips likely supported powerful muscles, aiding in holding and subduing prey.
Potential Prey Species
Acrocanthosaurus lived alongside a variety of large herbivorous dinosaurs, which formed the bulk of its diet. Its primary prey consisted of sauropods, large long-necked dinosaurs, and ornithopods, a group of bipedal or quadrupedal plant-eaters. Dinosaurs such as the enormous sauropod Sauroposeidon and the ornithopod Tenontosaurus coexisted with Acrocanthosaurus in its North American habitat.
While a full-grown Sauroposeidon would have been a challenging target due to its immense size (estimated at 40-60 tons), younger, sick, or old individuals were more vulnerable. Acrocanthosaurus was the largest predator in its environment, an apex predator. Although its main strategy was active predation, it likely also scavenged carcasses when opportunities arose.
Fossil Insights into Feeding Habits
Direct fossil evidence provides insights into the feeding habits of Acrocanthosaurus. Fossilized bite marks on the bones of contemporary herbivorous dinosaurs offer evidence of its predatory activities. For example, tooth marks matching Acrocanthosaurus dentition have been found on sauropod bones, including those of Sauroposeidon. These marks indicate that Acrocanthosaurus was capable of hunting and feeding on even very large sauropods.
Trace fossils, such as trackways, also offer clues, though their interpretation is more speculative. Recent discoveries have identified Acrocanthosaurus tracks alongside those of large sauropods like Sauroposeidon, suggesting potential predator-prey interactions. While coprolites (fossilized feces) containing bone fragments could theoretically provide direct dietary evidence, attributing them specifically to Acrocanthosaurus remains difficult. The cumulative fossil evidence consistently positions Acrocanthosaurus as a carnivore capable of taking down large prey.