The carnivorous dinosaur Allosaurus has been known since the late 1800s. This theropod was first documented in 1869.
- Allosaurus fragilis meaning "fragile, different reptile" lived approximately 145-150 million years ago during the Late Jurassic Period, with a recorded geographic range in Wyoming, Montana, Colorado, New Mexico, South Dakota, Utah, Oklahoma and Portugal (Glut, 1997; Prez-Moreno and Chure, 1999).
- It is known to reach 12 meters in length, 4.5 meters in height, and may have weighed up to 2 tons as an adult.
- A fragilis was one of the top predators of its time and is found primarily in the Morrison Formation.
- It lived on the lowland floodplains of the Western Interior in an environment similar to some of the large plains of Africa today (Russell, 1989).
- Allosaurus was the most common large carnivore of the Late Jurassic in North America.
- Strong forelimbs with sharp claws, powerful hind legs and recurved, dagger-like teeth are evidence that Allosaurus was a formidable predator.
- During the Late Jurassic, herds of plant-eating sauropods (such as Apatosaurus) were constantly on the move in search of food to satisfy their large appetites.
- Predators, such as Allosaurus, may have followed these herds, preying on the young and weak.
- Although it was much smaller than the sauropods, quite possibly Allosaurus hunted in packs to bring down larger prey. Like many meat eaters, it may also have been a scavenger.