Behind the debut of Dinosaur Star, there are 19 fractures

In the Late Jurassic, an Allosaurus limped toward a dry riverbed. The wound on the third toe of its right foot was swollen and ulcerated so badly that the pain made every step it took extremely painful. The dry season had not yet ended, and hunger and thirst had defeated the Allosaurus' last line of defense.

In the desolate wilderness, the Allosaurus fell. It slept quietly for 145 million years until a bipedal beast called a human chiseled away the rock, allowing the prehistoric predator to see the light of day again...

Allosaurus Recovered

In 1991, a scientific expedition team led by Swiss paleontologist Kirby Siber discovered an extremely well-preserved Allosaurus fossil in Wyoming, USA. This specimen has a bone preservation rate of nearly 95%, and is one of the most complete Allosaurus fossil specimens discovered so far. This 7-meter-long Allosaurus was not yet an adult, a young man. Scientists gave this Allosaurus fossil numbered MOR 693 a nickname - "Big Al".

Big Al, on display at the Museum of the Rockies in Montana | Tim Evanson / Wikimedia Commons

Allosaurus lived in the Late Jurassic 155-145 million years ago. It belonged to the Allosauridae family of theropod dinosaurs and was widely distributed in today's United States, Portugal and Tanzania. Judging from the number of fossils, Allosaurus is undoubtedly one of the most successful dinosaurs in the Jurassic. Allosaurus is about 7-10 meters long, with an average body length of 8-8.5 meters and a weight of more than 2 tons. They have a skull about 80 centimeters long and more than 70 sharp teeth in their mouths. Through scanning of the brain structure, scientists found that the olfactory bulb in the brain of Allosaurus is very large, indicating that they have a keen sense of smell.

In 1996, at the same location, researchers discovered another very complete Allosaurus skeleton, which they named "Big Al Two" | Marc Majcher / Wikimedia Commons

The most striking part of Allosaurus is the pair of horns above the eyes, the size of which may vary according to the age and gender of the individual. These horns look majestic, but they are actually just a pair of fragile ornaments, which may only be used to attract the opposite sex during the breeding season, and cannot be used as weapons in fighting.

Compared to its sturdy hind legs, the forelimbs of Allosaurus are much shorter, but the ratio of the length of the forelimbs to the hind legs is still much greater than that of Tyrannosaurus. Its hands have three fingers, and the ends of the fingers have curved claws that can be up to 25 cm long. When hunting, these large curved claws can cut into the prey's body.

Reconstruction of Allosaurus | Fred Wierum / Wikimedia Commons

A short life full of scars

As we all know, the formation of dinosaur fossils requires extremely harsh environmental conditions, so most of the dinosaur fossils excavated by scientists are fragmentary, and well-preserved ones are very rare. Large dinosaur fossils like Big Al, which are almost complete, are even rarer treasures in the world. Therefore, since the moment it was unearthed, Big Al has been the focus of the world's expectations. Not only was there a film crew following its excavation process, but its name also appeared in the headlines of major media.

Some fragmentary Allosaurus fossils | Jens Lallensack / Wikimedia Commons

However, as the research deepened, paleontologists discovered that Big Al's youth was very bitter: in its short life, it had 19 fractures and infections all over its body - its spine, pelvis, fingers, etc. had multiple injuries, and 5 ribs were broken. Among the numerous scars, the most fatal one was the third toe of its right foot, which formed a huge callus after the fracture. After the infection, Big Al's toe suffered from osteomyelitis and did not heal for at least 6 months. It is not difficult to imagine that this would seriously affect Big Al's movements. Experts speculate that the disease on its feet made it lose its ability to hunt and eventually starved to death.

Violence: How Carnivorous Dinosaurs Survived

Why was Big Al plagued by injuries? The reason can be summed up in one sentence: violence, violence, violence. For most carnivorous dinosaurs, their lives were spent in fighting and killing. Hunting, courting, and dividing territory all involved fighting.

An image of Allosaurus consuming the carrion of a sauropod dinosaur. Charles R. Knight / Wikimedia Commons

Paleontologists have found definite Allosaurus bite marks on local sauropod dinosaurs, and they found that a stegosaurus also had a "U"-shaped wound on its bone plate, which was exactly the same as the mouth of Allosaurus. Faced with the attack of Allosaurus, these prey would naturally not sit still and wait for death. The whip-like tail of Diplodocus and the bone plates and spikes on the tail of Stegosaurus are not easy to mess with. Therefore, injuries are commonplace for carnivorous dinosaurs. In addition to Allosaurus, scientists have also found a large number of trauma marks on theropod dinosaurs such as Sinraptor, Tyrannosaurus Rex and Daspletosaurus, many of which were caused by their own kind.

The study found that Big Air II was also covered with scars, and the colored parts were all injured. | Foth C, et al. 2015. New insights into the lifestyle of Allosaurus (Dinosauria: Theropoda) based on another specimen with multiple pathologies. PeerJ 3:e940

Big Al's short but legendary life attracted the attention of many fans. The BBC did not miss this good material and launched a special episode of "Walking with Dinosaurs" in 2000 - "The Mystery of Big Al", telling the story of Big Al from birth to death. As a result, Big Al stood out from many Allosauruses and even became as famous as the Tyrannosaurus Rex "Sue", becoming one of the most famous dinosaur stars in history.

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