Allosaurus (Allosaurus fragilis) was a large predatory dinosaur from the Jurassic Period and is often considered the dominant theropod of Late Jurassic North America. It lived in the same ecosystems as famous giant sauropods such as Apatosaurus and Diplodocus, making it one of the best-known predators of the Morrison Formation.
Time Period
Allosaurus lived in the Late Jurassic. In your site filter, this is grouped under Jurassic, a time when massive herbivores and large predators shaped dinosaur communities across western North America.
Habitat
Most Allosaurus fossils come from the Morrison Formation in the western United States. The Morrison is commonly reconstructed as a landscape of rivers, floodplains, and seasonal dry periods, supporting large herds of plant-eaters and the predators that followed them.
Size and Appearance
Allosaurus typically measured around 8.5–10.5 meters long. It had a large skull with sharp, serrated teeth, strong neck muscles, and powerful hind legs. Bony ridges above the eyes gave the head a distinct profile and may have played a role in display or species recognition.
Diet and Hunting
As a carnivore, Allosaurus preyed on other animals, potentially including juvenile or weakened sauropods. Many scientists propose that it used repeated, forceful bites and rapid head movements—more like a series of slashing strikes than a single bone-crushing bite. Its build suggests a combination of strength, agility, and endurance hunting.
Why Allosaurus Matters
Allosaurus is known from abundant fossils, including partial skeletons and large bonebeds. This rich fossil record makes it one of the most important dinosaurs for studying theropod growth, variation, injuries, and predator-prey dynamics in Jurassic ecosystems.
