Height : 2.75 m (9ft)
Length: 8.5 m (28 ft)
Weight : 1.5 tonnes (1.65 tons)
Allosaurus was a large carnivorous theropod that lived around 155 to 145 million years ago during the Jurassic period. It was the top predator of its time and would have preyed on most large herbivores and even some smaller carnivores. With a massive head balanced by a long stiff tail, short fore limbs and strong muscular hind limbs Allosaurus resembled a smaller version of the well known T-rex but was not a relative, preceding it by 90 million years or so. Allosaurus had a pair of distinctive horns above and in front of the eyes. The massive head contained many serrated that came out easily and were replaced when they did.
Allosaurus is claimed by some to have hunted in packs. However this is contested by some palaeontologists who say that fossilised groups of specimens are probably individuals that were incidentally killed whilst collectively feasting on a single carcass.
The name Allosaurus was formally given by palaeontologist Othniel Charles Marsh in 1877. Allosaurus means "Different Lizard" and is a combination of the Greek word allos, meaning "strange" or "different" and sauros, meaning "lizard". The name came about due to its vertebrae being different, having lightening features in them.