As shown in the image above: Tyrannosaurus rex may fight each other for mates, territories, or higher status.
Tyrannosaurus rex will bite each other's face maliciously, but may not have the intention of killing the other person. Instead, a new study has found that these aggressive Tyrannosaurus rex may be the result of different individuals competing for loot, such as territory, companionship or higher status.
The researchers came to this conclusion after analyzing 324 scars on the caps and jaws of 202 Tyrannosaurus rex dragons. Immediately, the team realized that the young Tyrannosaurus rex had no bite marks on its face. Conversely, about half of the older Tyrannosaurus rex had scars, suggesting that older members of only one gender may have been involved in these fights.
Caleb Brown, director of the Royal Tyrell Museum in Alberta, Canada, said: "Taken together, we can piece together how these animals fight. They are likely to pretend, look at each other, and then try to bite each other's head with their mouths. ”
As shown in the image above: The upper jawbone of the snake-haired female monster dragon has scars.
Tyrannosaurus rex was a group of carnivorous dinosaurs that dominated Asia and North America as a top predator during the last 20 million years of the Cretaceous Period (145 million to 66 million years ago). The project's research began with the discovery of a fossil T. rex: a piece of upper jaw bone unearthed in Alberta's Dinosaur Provincial Park in 2017. Brown believes that an analysis of the jawbone of the Tyrannosaurus rex revealed that it had a long series of scars that curved on one side of the bone. These are most likely tooth marks left by another Tyrannosaurus rex that healed to form these ridges of bulges.
Tyrannosaurus rex skulls usually have a lot of scars, but no one has done a lot of research on these scars and systematically examined them. So Brown and his colleagues began documenting the occurrence, shape, and other details of these scars on the Tyrannosaurus rex bones, including Alberta dragons, Dasbrey dragons, and snake-haired monster dragons.
As shown in the image above: A synthetic pattern of facial scars shows the density and direction of the impact.
The team found that facial scars are very common. About 50% of large, underage Tyrannosaurus rex and 60% of adult tyrannosaurs have bite marks on them. In addition, scars are more common in the upper and lower jaws, including marks of tooth punctures and elongated scars.
The team compared the spacing between the teeth of the "victim" and the "biter" based on the skull and bite marks, thus determining their size.
Brown believes that the data shows that the body size of these animals is roughly similar. Tyrannosaurus rex did not bite each other like this when they were young, and only began to do so in adulthood, and this was only the case in animals of the same size. In addition, the prevalence of these scars, which are terrible but not usually fatal, suggests that older Tyrannosaurus rex often fought each other.
As shown in the image above: This chart compares the facial scars of different theropod dinosaurs.
Modern animals also kill each other, usually after they have matured sexually. "These animals are of breeding age and they're testing the waters to see how strong they are with their competitors," Brown said. Or can they be mated with their potential spouses? Tyrannosaurus rex may also start fighting each other for sexual maturity, but it's really hard to test, so we actually can't figure it out. ”
Determining the sex of dinosaurs is almost impossible. Unless the dinosaur died while pregnant or laying eggs, scientists cannot distinguish between male and female dinosaurs.
As shown in the image above: Study leader Caleb Brown examines Albertalong's jaw.
"We don't know if there were only male dinosaurs, or only female dinosaurs, or if both dinosaurs had biting and fighting, but it's interesting to consider these possible scenarios, especially if we can better determine the sex of dinosaurs in the future," Brown said. ”