Allosaurus

Authored by Pixtarsaurus

Allosaurus ("different lizard") was the most common predator of the Late Jurassic period and the most dangerous. Like most meat-eating dinosaurs, its jaws were filled with serrated teeth shaped like blades. Computer studies suggest that Allosaurus attacked by using its upper jaw like a machete to hack at its victim, then it used its lower jaw to bite out a slice of meat, although recent studies have proven this unlikely. In terms of size, it was the third largest theropod of its era, only the likes of the megalosaurid Torvosaurus (10-11 meters or 33-36 feet with a 4-5 tons of weight behind it) or Saurophaganax (12-13 meters or 40-43 feet with 6 tons of weight behind it) exceeded it in size and weight. It averaged around 8.5 meters long (28 feet) and around 3 meters (10 feet) tall. However fragmentary remains suggest lengths of 11 to 12 meters (36-40 feet), though its weight would be less than the Torvosaurus, which was the heavy weight theropod of the Jurassic.

It might have been easy for an Allosaurus to kill a fairly defenseless dinosaur-like Camptosaurus, but Stegosaurus could certainly fight back, and the sauropods (giant long-necks) were so huge that they could easily crush even an adult Allosaurus with a blow from their tail, or a stomp from their legs. Thus it is thought that the Allosaurus hunted in large hunting gangs, similar to that of the Komodo dragon. While this means they hunted 'together', it was still every Allosaur for itself. Often times, an entire gang of these dinosaurs would be killed by their prey or by natural hazards, showing they had poor group planning.

It is known that Allosaurus led a dangerous life. The Allosaurus on display at the Smithsonian Institute has a smashed shoulder blade, many broken ribs, and a lower jaw so damaged that paleontologists didn't realize it was an Allosaurus jaw for over 100 years! But these were tough dinosaurs: Their bones show that they lived long enough for their wounds to heal.