
- Species Type: Allosaurus Fragilis
- Type of Dinosaur: Theropod
- Period: Late Jurassic
- Diet: Meat (carnivorous)
- Lifespan: 25 to 30 years
- Length: Up to 28 feet (average)
- Weight: 2,200 pounds (average)
21 Allosaurus Facts for Kids
- The Allosaurus was discovered in 1877, by Othniel Charles Marsh in Colorado, USA.
- The Allosaurus got its scientific name Allosaurus Fragilis in 1877, from Othniel Charles Marsh.
- The name Allosaurus means: “Different Lizard”.
- The name Allosaurus is pronounced: “AL-uh-SAWR-us”.
- The Allosaurus was part of a group of dinosaurs known as Theropods.
- They lived during the Late Jurassic Period between 150 and 155 million years ago.
- Paleontologists recongize three different species of Allosaurus, and they are A. fragilis (type species), A. europaus, and A. jimmadseni.
- Estimates put the average length of an Allosaurus around 28 feet.
- Estimates put the average weight of an Allosaurus around 2,200 pounds.
- Estimates put the top running speed of an Allosaurus around 21 miles per hour.
- The Allosaurus had an estimated lifespan of up to 28 years.
- Paleontologists believe an Allosaurus was fully grown and reached sex maturity around the age of 15.
- The Allosaurus was an active carnivore and paleontologists believe they hunted large sauropods in a group.
- The jaw of the Allosaurus was double hinged, which allowed them to open their mouths extremely wide.
- An adult Allosaurus had between 33 and 39 large teeth
- The teeth from Allosaurus fossil specimens are on average three to four inches in length.
- Allosaurus teeth are commonly found by paleontologists because they frequently would frequently lose and replace them.
- Based on recovered fossil specimens, paleontologists believe the Allosaurus may have frequently attacked Stegosauruses. A vertebra from an Allosaurus had damage from what appeared to be a Stegosaurus tail. A Stegosaurus neck bone had a bite mark that matched to an Allosaurus.
- A 95% complete Allosaurs fossil specimen called Big Al was discovered near Shell, Wyoming, in 1991. In 1996, the same team that discovered Big Al unearthed another Allosaurs fossil specimen called Big Al Two, and it was more complete than Big Al.
- The Allosaurus was the first dinosaur to ever appear in a movie, the 1925 film The Lost World.
- In 1988, the State of Utah officially designated the Allosaurus as the official state fossil.
Allosaurus Pictures

The Allosaurus exhibit at the San Diego Natural History Museum.Credit: Unknown

A museum exhibit of an Allosaurus fighting with a Stegosaurus.Credit: Unknown

The Allosaurus exhibit at the Brussels Museum of Natural History.Credit: Grizzlysaurus152 / Reddit

A close-up view of an Allosaurus skull.Credit: Dave Hone

A diagram of an Allosaurus skull.Credit: USU Eastern Prehistoric Museum

Allosaurus and human size comparison.Credit: Facts Just for Kids
Additional Resources on Allosaurus
- Allosaurus fragilis @ Wikipedia – Learn more about the Allosaurus on the Wikipedia website.
- llosaurus fragilis @ National Park Service – Get more Allosaurus facts for kids on the U.S. National Park Service website.
- Allosaurus fragilis @ Natural History Museum of Utah – Find more interesting facts about Allosaurus on the Natural History Museum of Utah website.
- Allosaurus: Facts About the ‘Different Lizard’ – Read about the Allosaurus on the LiveScience website.