Allosaurus was one of the largest theropods to have ever existed and inhabited Africa, Europe, and North America about 150 million years ago. The Allosaurus was a genus of the large Carnosaurian dinosaurs, which consists of other theropod dinosaurs.

Key facts

Allosaurus pronunciationThis species is pronounced as “AL-oh-saw-russ”
What does Allosaurus mean?The name, Allosaurus, is derived from two Greek words which are “allos”, which means different, and “saurus”, which means lizard. They were named like this due to having different vertebrae from other dinosaurs that existed at the time.
Dinosaur typeTheropod
On the menuCarnivore
Length12.1 meters (39.7 feet) for females
10.4 meters (34.1 feet) for males
Height3.8 meters (12.5 feet) for females
3.2 meters (10.5 feet) for males
Weight2.3 tons (4,600 lbs)
Life expectancyScientists have concluded that an Allosaurus may have reached full adulthood at 15 years old, and have been expected to live until 28 years old.
Legs used to get aroundAllosaurus had four legs, but their hind legs were much longer than their rear legs, which means that they were bipedal and were known to have used their front legs as a way to attack their prey.
Estimated top speedDue to the Allosaurus’ massive body and two powerful hind legs, researchers show that they can reach up to 33.8 kp/h or 21 mp/h.
When they livedThe Allosaurus lived during the Late Jurassic Period 150-144 million years ago.
Where they have been found?The fossils of the Allosaurus were found in Utah’s Cleveland-Lloyd Quarry, which contains other dinosaur bones that have been found.

When & Where

The first discovery of the Allosaurus was found in 1869, which was likely to be retrieved from Morisson Formation strata near Granby, CO. In 1877, the fossil was named by Othniel Charles Marsh with the name Allosaurus fragilis, which means a different lizard. The name was given after O.C. Marsh studied the fossil, and discovered that it has features that made the vertebrae lighter.

Size & Weight

Being one of the largest theropods to ever exist, the Allosaurus can weigh about 2.3 tons, which is about 4,600 lbs. Their height also varies depending on the male and female Allosaurus. For female Allosaurus, their height can reach up to 3.8 meters, which is about 12.5 feet. For males, they can reach a height of 3.2 meters, or about 10.5 feet. Their lengths also differ as females can measure up to 12.1 meters or 39.7 feet and males can reach about up to 10.4 meters or 34.1 feet.

Mobility & Diet

Just like other theropods, the Allosaurus is a carnivore, which means that they feed on other dinosaurs to live. Scientists believed that the Allosaurus likely ate other large herbivores such as sauropods, ornithopods, and the stegosaurus. Other fossil evidence has shown bite marks on sauropods and stegosaurus that match that of an Allosaurus.

Interesting Points

  • Allosauruses used to be known as Antrodemus, which means “body cavity” in Greek.
  • They liked to munch or tussle with a stegosaurus, another kind of dinosaur to exist before
  • This type of dinosaur sheds or replaces its teeth occasionally and weighs about three or four inches in length per tooth
  • They have at least seven species that have been found
  • The most famous fossil found of an Allosaurus is named “Big Al”, which can be found at the heart of the University of Wyoming campus.
  • Upon discovery of the fossils, the vertebrae of the Allosaurus fragilis (Latin for “fragile”) were concave on both sides and contained shallow cavities, giving them an hourglass shape, which is different from the other dinosaurs to exists during that time.