FANDOM Allosaurus. Now, these are the lions of the Jurassic. The top predators of their age.
— Allen, about Allosaurus
in Time of the Titans

Allosaurus (al-oh-saw-us; name meaning "Different Lizard") is a genus of theropod dinosaur that originated during the Late Jurassic period in what is now North America. Credited as the "Lions of the Jurassic", Allosaurus was the apex predator of its time. A strong, ferocious carnivore and one of the world's best-known dinosaurs, Allosaurus was also among the largest theropod dinosaurs, measuring 11 meters long, standing 5 meters tall, and weighing 5 tons.

One of the primary animals of the park, Allosaurus was first encountered in the episode Time of Giants. A pair of them persued the team. However, one individual Allosaurus was rescued from the Late Jurassic of 145 million years ago in Wyoming and brought back to the park. The individual, Big Al, resides in Allosaurus Forest with his mate Alice, a female Allosaurus.


Era & DiscoveryEdit

Allosaurus lived during the Late Jurassic Period from 156–145 million years ago, ruling Western North America for 11 million years. Said to be the king or "lion of the Jurassic", Allosaurus was the largest and apex predator of its time. It shared its environment with other creatures like Ornitholestes, Anurognathus, Brachiosaurus, Diplodocus, Apatosaurus, Stegosaurus, Dryosaurus, and Othnielia.

Allosaurus was first discovered by Othniel Charles Marsh in 1877 and has since become one of the most famous dinosaurs in the world. Allosaurus was among the largest predatory dinosaurs of the Late Jurassic and was also among the largest predators until the Tyrannosaurs appeared over 50 million years later.

Physical AttributesEdit

As the largest theropod dinosaur of its time and the first giant predatory dinosaur ever to walk North America, Allosaurus was a large carnivorous dinosaur. In fact, on average, measuring 30–40 feet (9–12 m) long, standing 13–16 feet (4–5 m) tall, and weighing up to 3–5 tons (6,000–10,000 lbs), Allosaurus was one of the largest carnivorous dinosaurs that ever walked the Earth. However, the largest Allosaurus ever discovered stood about 16.5 feet (5 m) tall, measured 45 feet (13 m) in length, and weighed up to 6.5 tons (13,000 lbs.), making it a huge carnivorous dinosaur almost as large as Tyrannosaurus rex.

Even at that large, Allosaurus was such a massive predator, but they were just as fast, quick, and agile as their two little ancestors: Coelophysis and Liliensternus. Allosaurus had to eat their own weight in food every month, which is equivalent to about as much as over 40 humans. From the moment they hatch from their eggs, an individual of Allosaurus could reach their full adult size in just seven short years, give or take.

Allosaurus had a skull that measured three feet long, with a pair of blunt crests just above its eyes, in the orbital region. Allosaurus also had large, powerful jaws with long, sharp, serrated teeth that were 2–4 inches long. Movable joints and elastic ligaments in Allosaurus jaw and skull flexed to help the teeth tear and slice through the prey. The flexible jaws stretched widely to allow the creature to swallow large mouthfuls of flesh. These teeth were curved inward, shaped like a "V" to help secure its prey. 

Allosaurus had a bulky body, a massive tail, and thick bones. It had a strong S-shaped neck and had vertebrae that were different from those of other dinosaurs, hence its name. Running on two muscular, bird-like legs at speeds as fast as 20 mph, Allosaurus preyed upon the large herbivores of the period, including large sauropods, and smaller plant-eaters. The forelimbs were short but muscular and had three-fingered tipped hands with a sharply curved claw up to 15–25cm (6–10 inches) long for holding prey. The powerful jaws were lined with over 70 sharp 8cm (3 inches) long teeth. 

Capabilities and WeaponryEdit

  • Claws: Allosaurus killed its prey with the sharp talons on its arms and legs.
  • Speed: Allosaurus was a fast dinosaur, able to run at speeds in excess of 20 miles per hour.
  • Strength: Despite its weaker jaws strength, Allosaurus was also a very physically strong dinosaur, able to toss anything that ways 2 tons.
  • Teeth: Allosaurus possessed sharp, saber-like teeth.

Behavior & TraitsEdit


Allosaurus pair

Like many large predators, Allosaurus was a pack hunter, possibly lying in wait to ambush prey. It could hunt in pairs, packs of three (which was their most common number), groups, or even numbers of over half a dozen individuals. But when hunting a herd of larger prey, such as Diplodocus, the Allosaurus pack would split up in between a Diplodocus herd, literately running through and around the herd, break it up, and eventually isolate the young, old, weak, sick, and injured members of the herd.


When the hatchlings of female Allosaurus were born, the smell was important to Allosaurus and from the moment the mother and hatchling Allosaurus smelled each other, they formed a bond that was crucial to the hatchlings early survival. Hatchling Allosaurus ate insects and other small animals.


As young Allosaurus reached their first to the second year of life, they grew to almost 10 feet (3 m) and, by then, would no longer be hunting insects, but hunting other, smaller herbivorous dinosaurs, such as Dryosaurus and Othnielia. Despite that, they were still small Allosaurus and they were not a match for almost all other dinosaurs on their environment, such as a female Ornitholestes protecting her nest.

By the time a juvenile Allosaurus was five years of age, they already reached about 30 feet (9 m) long, however, they were not yet fully grown. Despite that, they were old enough and large enough to hunt larger dinosaurs, such as Stegosaurus and even the large sauropod dinosaurs like Diplodocus.

When Allosaurus lived to be six years old, as a sign of age, the crests over their eyes would gain a darker shade of red. Sexual maturity was dependent on an Allosaurus's size and at 33 feet (10 m) long, young Allosaurus were well on their way to be big enough. However, even by that time, they were actually mature adolescents rather than full-sized adults.

Upon Allosaurus reaching their full size, they quickly established their dominance over predatory dinosaurs, especially other Allosaurs. When gigantic predators get to the size of a fully grown Allosaurus, most of those predators rarely had to bring down their own food. They just scavenged other kills.

Journal EntryEdit

Credited as the Lions of the Jurassic, Allosaurus, or "Other Reptile", was the apex predator of the Late Jurassic Era. Measuring 38 ft. in length and weighing more than 4500 kilograms, this carnivore was one of the largest predatory dinosaurs that ever walked Planet Earth.

Equipped with serrated teeth, sharp claws, and powerful arms and legs, Allosaurus was a deadly, fast, and powerful carnivore that could run at a speed of 20 miles per hour.

Allosaurus was also a pack hunter, in which case, allowed it to bring down the heavily-armored Stegosaurus and even the large sauropod dinosaurs of its environment, whereas alone, it hunted smaller prey such as the ornithopods. When hunting a herd of sauropods, the Allosaurus pack would run in between the members of the herd, separate them, and isolate the sick, old, weak, and injured members.

Like all animals, female Allosaurus also cared for their young. From the moment they are born, the hatchling and mother smell each other and then form a bond that was important to the hatchling's survival early in life. An individual Allosaurus could reach its full size within seven years.

— Allen, in his Journal, about Allosaurus



  • Allosaurus was the very first giant predatory dinosaur to be brought to the park, which is coincidental since it was the very first giant predatory dinosaur ever to walk North America.
  • The sound effects for the Allosaurus are that of a lion, tiger, and altered vulture sounds as well as some classical ambient dinosaur roars.
    • Lion sound effects seem to fit well for Allosaurus, since they are described as being the "lions of the Jurassic."
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