Allosaurus

Allosaurus averaged about 8.5 meters (28 feet) long, with the largest specimens estimated at 9.7 meters (32 feet). It weighed around 2,700 kilograms (about 6,000 pounds).13

Allosaurus was a meat-eater that hunted large plant-eating dinosaurs like Stegosaurus, Diplodocus, and other ornithopods, stegosaurids, and sauropods. It may have also scavenged on dead dinosaurs.13

Allosaurus lived during the Late Jurassic period, about 155 to 143 million years ago. Some sources say 152 to 145 million years ago.13

Most Allosaurus fossils come from North America's Morrison Formation, but some have also been found in Portugal. It lived in what is now the USA.13

No, Allosaurus was smaller than T. rex. Allosaurus was about 8.5 to 9.7 meters long, while T. rex reached lengths of 12 to 13 meters.1

Scientists aren't sure. Some think Allosaurus may have hunted in packs, but others think it was a solitary predator that only gathered in groups sometimes. There's evidence for both ideas.13

Up to about 34 km/h (21 mph), about as fast as a fast human runner. A computer model of its legs and muscles worked this out. Its big, strong legs were made for running after prey.1

The sources don't mention feathers on Allosaurus. It is known to have had scaly skin, but no feather fossils have been found.1

Allosaurus means 'different lizard' in Greek. It got this name because its backbone bones were light and hollow, which was unusual for a dinosaur of its size.1

The sources don't say whether Allosaurus could swim. It was a land dinosaur that walked on two legs, so it probably didn't swim often.1