Elton Publications: Allosaurus

What were Allosaurs?

Allosaurs were fierce meat eating dinosaurs (carnisaurs) that live in many places around the Earth. Fossils have been found in North America, South America, Africa, Asia, Europe, Australia and Antarctica.

How did Allosaurus move?

Allosaurs walked on two legs. Did they also run? Some scientists think that they could not have run very fast. If they fell while they were running, they would have been hurt because their small front arms were too weak to stop them falling hard onto the ground.

Then an Allosaurus was found. It had lots of broken ribs that had healed. This showed that the Allosaurus did run, and probably ran very quickly when it hunted.

How big was Allosaurus?

In North America, Allosaurs were up to 12 metres long and 5 metres tall.

In 1979, Dr Tim Flannery found an ankle bone of a dinosaur in Victoria. (See Link 4) The bone belonged to an Allosaurus. The bone was compared to Allosaurus bones from North America. From the size of the bone, scientists predicted that Australian Allosaurus was much smaller. They would have been about 6 metres long and 2 metres tall.

Why was Australian Allosaurus smaller?

No-one knows for sure. However, Australian Allosaurus lived in a very cold dark place. Victoria, where the bones have been found, was much closer to Antarctica than it is now. It would have been very cold and dark for six months of the year. Perhaps smaller animals didn't feel the cold as much as big animals.

When did Allosaurus live?

Interesting! In North America, Allosaurus died out about 150 million years ago. In Australia, it survived until 110 million years ago. Why did it survive much longer in Australia? No-one knows why.