Question 1

How do you say Allosaurus?

Accepted Answer

Allosaurus is pronounced AL-oh-saw-russ, with the stress on the first syllable. Break it into four parts: AL, then oh, then saw, then russ. The ending sounds just like the word 'russ' in the name Russell. Most people get it right on their first try once they see it broken down that way.

Question 2

What does Allosaurus mean?

Accepted Answer

Allosaurus means 'different lizard' in Ancient Greek. The name comes from two Greek words: allos, meaning different or other, and sauros, meaning lizard. Paleontologist Othniel Charles Marsh chose the name in 1877 because the vertebrae of this dinosaur had hollow air pockets inside them, which he thought was completely unlike anything seen before. He was trying to capture just how unusual the fossil bones looked compared to other large animals of the time.

Question 3

How big was Allosaurus?

Accepted Answer

Allosaurus was a genuinely massive predator, typically reaching about 28 to 39 feet long and standing around 16 feet tall at the hips. It weighed roughly 4,400 pounds, which is about the same as a large pickup truck. The skull alone could be up to 3 feet long, packed with serrated teeth up to 4 inches in length. Some fragmentary fossils suggest even larger individuals may have existed.

Question 4

Was Allosaurus dangerous?

Accepted Answer

Yes, Allosaurus was one of the most dangerous predators of its time and place. It had 3-foot-long jaws lined with serrated dagger-like teeth, 6-inch claws on its hands, and a hunting technique that may have involved driving its upper jaw into prey like an axe. Fossil evidence shows bite marks from Allosaurus on the bones of enormous sauropod dinosaurs, meaning it regularly tackled prey far larger than itself. Healed wounds on Allosaurus skeletons also tell us these animals fought hard and survived serious injuries.

Question 5

When did Allosaurus live?

Accepted Answer

Allosaurus lived during the Late Jurassic period, roughly 155 to 143 million years ago. To put that in perspective, this was about 90 million years before Tyrannosaurus rex appeared on Earth. The world during Allosaurus's time had no grass, no flowering plants, and no birds as we know them today. The continents looked very different, and North America was warm, humid, and home to some of the largest animals that ever walked the planet.

Question 6

How does Allosaurus compare to T. rex?

Accepted Answer

Allosaurus and T. rex are often compared, but they lived so far apart in time that they never encountered each other. T. rex was significantly larger and heavier, with much more powerful bite force. However, Allosaurus had longer arms with functional three-fingered hands and claws, which T. rex lacked almost entirely. Allosaurus also had a more lightly built skull that may have allowed faster, repeated strikes, while T. rex had a bone-crushing bite designed for maximum force. They were apex predators built for very different hunting strategies.

Question 7

Where was Allosaurus found?

Accepted Answer

The vast majority of Allosaurus fossils have been found in the Morrison Formation, a massive geological unit stretching across the American West through states including Utah, Colorado, Wyoming, and Montana. Significant material has also been discovered in Portugal, in formations called the Alcobaca, Bombarral, and Lourinha formations, suggesting that similar predators roamed on both sides of the ancient Atlantic. The single richest site is the Cleveland-Lloyd Dinosaur Quarry in Utah, which has produced over 10,000 individual bones.

Question 8

Did Allosaurus hunt in packs?

Accepted Answer

This is one of the most debated questions in Allosaurus science. Some paleontologists, including Robert Bakker, have argued that multiple Allosaurus individuals found near large sauropod kill sites suggest cooperative hunting. Others point out that those bone accumulations might simply reflect multiple animals independently scavenging the same carcass or being trapped together during drought conditions. Right now the honest scientific answer is that we do not know for certain, and researchers continue to study this question using fossil behavior evidence.

Question 9

Who discovered Allosaurus?

Accepted Answer

The first fossils that could definitively be assigned to Allosaurus were described by Othniel Charles Marsh in 1877, based on bones found in Colorado. Marsh was a Yale paleontologist famous for his fierce rivalry with Edward Drinker Cope in what became known as the Bone Wars. However, it was James Madsen Jr.'s 1976 monograph on the Cleveland-Lloyd Quarry material that truly established Allosaurus as one of the best-understood large theropods in the fossil record.

Question 10

What did Allosaurus eat?

Accepted Answer

Allosaurus was a pure carnivore that preyed on the giant animals sharing its Jurassic world. Fossil evidence in the form of bite marks on bones confirms that it attacked large sauropod dinosaurs like Brachiosaurus and Camarasaurus, as well as armored dinosaurs like Stegosaurus. One Stegosaurus tailbone fossil has been found with an Allosaurus-shaped bite mark punched through it, and an Allosaurus pubic bone from the same quarry has a puncture wound that matches a Stegosaurus tail spike perfectly, proof of a real fight that happened over 150 million years ago.

Question 11

How smart was Allosaurus?

Accepted Answer

Allosaurus was probably about as intelligent as a large modern crocodile, perhaps a bit more so. Its brain was relatively small compared to its body size, but it had well-developed olfactory regions suggesting a strong sense of smell. Its eyes were positioned to give some degree of binocular vision, which is a trait associated with active predators that need to judge distance accurately. Scientists do not believe it had the social intelligence of modern wolves, but it was clearly a capable and effective hunter based on the fossil evidence of its prey.

Question 12

Is Allosaurus the same as Antrodemus?

Accepted Answer

For much of the 20th century, Allosaurus was incorrectly referred to as Antrodemus in many scientific papers and books. The name Antrodemus was based on a single incomplete bone fragment described in 1869, and it was assumed to belong to the same animal. When James Madsen Jr. conducted a thorough analysis of the Cleveland-Lloyd Quarry fossils in 1976, he concluded that Allosaurus was the correct and valid name, and Antrodemus was set aside. So if you see an old book calling this dinosaur Antrodemus, it is talking about the same creature.

Question 13

Who was Big Al the Allosaurus?

Accepted Answer

Big Al is the nickname for one of the most famous Allosaurus fossils ever found, officially catalogued as specimen MOR 593. It was discovered in Wyoming in 1991 and is about 95 percent complete, making it one of the most intact Allosaurus skeletons known to science. CT scans revealed that Big Al had suffered from multiple bone infections, stress fractures in its feet, and broken ribs during its lifetime, giving scientists a remarkable window into the hard and often painful life of a Jurassic predator. Big Al was the subject of a BBC Walking With Dinosaurs special in 2000.

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