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Discovering Allosaurus – The Fearsome Predator of the Late Jurassic

Allosaurus – A Fearsome Predator

Imagine this: A predator that’s more fearsome than a lion, more cunning than a wolf, and fairly large. That’s an Allosaurus. It was one of the top predators of the Late Jurassic period. Today, we’ll learn more about this fascinating dinosaur!

Allosaurus Skeleton at San Diego Natural History Museum
Public Domain photo of Allosaurus Skeleton at San Diego Natural History Museum

The Discovery of Allosaurus

This dinosaur was discovered in the late 19th century, around 1877, by Othneil Charles Marsh. One of the largest fossil sites they found it in was the Morrison Formation in North America. He (Charles) was known for his role in the “Bone Wars.” This was a period of intense and competitive fossil hunting in North America.

One of the most famous specimens is “Big Al,” located in the Museum of the Rockies in Bozeman, Montana. The museum is known for its extensive collection of dinosaurs, and their contribution to paleontological research. Their Allo fossil is very well preserved.

Allosaurus Reconstruction - Fred Wierum
Fred Wierum, CC BY-SA 4.0, via Wikimedia Commons

Physical Characteristics

This theropod was, on average, 28 feet in length, and weighed 1.5 Tons. It stood in a bipedal stance, with a large skull that had sharp teeth. It had extremely strong hind limbs, and shorter forelimbs, like most theropods. Some unique parts of their design included the crests above their eyes and serrated teeth. It has been commonly used in comparisons with other carnivores, like Tyrannosaurus Rex.

Allo’s Behavior & Diet

It was a fearsome predator, for sure. It likely was an Ambush predator and may have hunted in small packs. There is evidence in the fossil remains that it was more predatory, and an active scavenger (more on the side). It mostly ate herbivores like Stegosaurus & sauropods! It most likely went for the older, weaker, or younger sauropods, since those herbivores were tough.

Their Ecological Roles

It lived approximately 155 – 150 million years ago. The Morrison Formation includes areas of Colorado, Utah, Wyoming, and others. It included several environments, like floodplains, river channels, and lakes. It was a semi-arid climate with distinct wet and dry seasons.

It was considered an Apex Predator of its time, among the top in the food chain. It may have been both an active predator and scavenged where it needed to. There’s fossil evidence they may have lived in packs, like Raptors. Especially when targeting larger prey like sauropods.

Significant in Scientific Communities

The Allo is significant in the scientific community. It has helped them understand the biology and behavior of dinosaurs. It has also allowed them to advance the technology they use, for example, 3D Modeling and CT scans. It has also given a fairly significant role in the Education communities, as well.

Concluding Thoughts

The Allo was indeed a very fearsome predator that lived in the late Jurassic period. You would not want to have one come up to “meet” you, since you would most likely be eaten by one! Unless, of course, that’s what you wanted! We would say that the Allosaurus was a successful predator of its time and that it didn’t have much in the way of others predating on it.


Thumbnail Allosaurus By:
File:Allosaurus Juvenile Reconstruction.jpg – Wikimedia Commons
File:Allosaurus jimmadseni skeletal.png – Wikimedia Commons

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Kenson M

Kenson M

Owner of Mesozoic Haven since 2015, when it was previously known as Jurassic Kingdoms. Is a family-friendly content livestreamer and lives in Texas.View Author posts

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I would say that it’s going to be the height of Allosaurus that I found more fascinating. For it to be standing at 28 feet in length shows that it’s a freak of nature. It’s a shame we no longer have those beasts with us now.


For Allo to be 28 feet in length shows how huge it is. I would say that I wouldn’t want to be in a situation where I will be coming up against such type of creature.


No matter how big Allosaurus looks, it’s not going to be more intimidating then T-Rex to me. I fear T-Rex more than any other dinosaurs that have ever existed.

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