Allosaurus was a large bipedal dinosaur with a huge skull balanced by a long and heavy tail. Being a large and powerful meat eater with formidable teeth and a savage bite, Allosaurus would have been top dog in its Jurassic ecosystem. It would have been quick enough to outrun its very slow prey.
Allosaurus lived during the Late Jurassic and has been found primarily in North America's Morrison Formation, with a few fossils also known from Portugal. The Morrison Formation itself is a long stretch of ancient rock running from Montana, all the way to New Mexico. The rock formation allows us to step back in time to see a once verdant landscape of rivers, lakes, and vast plains – a perfect setting for such an awesome ecosystem.
Allosaurus had crocodile ears. It would have had poor hearing, only being able to hear low frequency sounds.
Allosaurus had backward facing teeth, which meant with each struggle, its hapless victim would be pushed further down the dinosaur's huge throat.
Allosaurus had a well-developed sense of smell, useful for sniffing out its prey.
Allosaurus droppings have been found to be 1.52m (nearly 5ft) in length and 10.2cm (4in) thick. That's a daunting amount of dung!
In 1991, near Shell in Wyoming, a Swiss team led by Kirby Siber unearthed the best-preserved fossil Allosaurus ever found. It was an almost complete skeleton dubbed 'Big Al'. Big Al had unfortunately died very young with massive injuries. As a consequence, he intrigued the media with his story and featured in the BBC Walking With Dinosaurs special 'The Ballad of Big Al'. Later on, the same team discovered a similar Allosaurus fossil which was even better preserved than Big Al. The fossil was named 'Big Al 2'.
Height: 5m (16.4ft)
Length: 12m (39.36ft)
Weight: 1.4 tonnes (1.57 short tons)
Top speed: 33.8kph (21.00mph)
Vision: Allosaurus had its eyes in front of its head facing forward, so that it would have been better able to work out distance and time to attack.
Skin: The skin of Allosaurus would have been smooth and leathery.
Brain: Allosaurus had an oval-shaped brain, about the size of a small loaf of bread, though probably not as tasty... unless you were another dinosaur.
Prey: Allosaurus was an active predator of large animals such as the long-necked Diplodocus and the plate-backed Stegosaurus. These were all found together at the same time in the same habitat and location.
Bite: The estimated maximum bite force of Allosaurus would be 3,500 newtons, less than alligators and leopards.