Allosaurus

When you think of apex predators of the dinosaur world, Tyrannosaurus rex might come to mind—but millions of years before T. rex ruled, Allosaurus was the top hunter of the Late Jurassic. With its massive jaws, bladelike teeth, and powerful build, this carnivore was built for dominance.

Basic Profile

Allosaurus(meaning “different lizard”) lived approximately 155 to 145 million years ago during the Late Jurassic period. It measured around 8.5 to 12 meters (28–39 feet) in length and weighed between 1.5 and 2.5 metric tons. This bipedal predator had a large skull filled with over 60 sharp, serrated teeth—perfect for slicing through flesh—and walked on two muscular legs, balanced by a long, heavy tail.

Lifestyle and Behavior

Paleontologists believe Allosaurus preyed on large herbivores of its time, including Stegosaurus, Camptosaurus, and even young sauropods. Some evidence suggests it may have hunted in packs, although this remains debated. It likely used ambush tactics, swinging its powerful upper jaw like a hatchet to deliver slashing bites rather than relying on brute force alone.

Despite its fearsome reputation, Allosaurus wasn’t invincible. Fossil evidence shows signs of injuries and even infections, suggesting it led a violent life. It may have lived up to 28 years, reaching full size by age 15.

Fascinating Facts

- Allosaurus was one of the most common large carnivores in North America’s Morrison Formation, making up 70–75% of theropod fossils found there.

- Its lower jaw could open extremely wide—similar to modern snakes—allowing it to gulp down large chunks of meat.

- The first Allosaurus appeared in the 1925 silent film 'The Lost World', making it the first dinosaur movie star.

- One of the most complete 'Allosaurus' skeletons, nicknamed “Big Al” was discovered in 1991 and is 95% intact, offering rare insight into its growth and injuries.

Recent Discoveries

Modern research continues to refine our understanding of “Allosaurus”. Studies suggest it had a metabolism somewhere between warm- and cold-blooded animals, and its teeth were constantly replaced throughout its life. New fossil finds in Portugal and possibly Africa hint at a wider geographic range than previously thought.

From its razor-sharp teeth to its starring role in early cinema, “Allosaurus” remains one of the most iconic and well-studied predators of the dinosaur age. Whether it hunted alone or in packs, one thing is clear: this Jurassic giant was a force to be reckoned with.