Recently, the research team from Canada has further research on the life habits of Tyrannosaurus rex. The researchers claim that scars on the bones of the Tyrannosaurus rex suggest that when the Tyrannosaurus rex fights with its own race for some reason, its main attack is to bite the opponent's face. The study further deduces that this may be a possible basis for judging the gender of T. rex. The study was published in the journal Paleobiology.
Tyrannosaurus rex, also known as Tyrannosaurs. Rex), active in the last 20 million years of the Cretaceous Period, was one of the last dinosaur species to become extinct. As ferocious and powerful carnivorous dinosaurs, they gained dominance in Asia and North America. Since the first excavation of the fossil bones of T. rex in the early twentieth century, the media and the public have been curious about this mysterious prehistoric hunter. The media has been gushing about paleontologists finding fossilized skeletons of prehistoric monsters in montana's wasteland, and the New York Times has referred to Tyrannosaurus rex as "the most horrific killing animal ever recorded."
Recently, a study from the Royal Canadian Tyrell Museum revealed how Tyrannosaurus rex fights each other – biting each other's faces. It is reported that after analyzing 202 skull bones and jaw fossils of the tyrannosaur dragon, the researchers counted 324 bite marks on these bones. Caleb Brown, head of the study and director of the Royal Canadian Tyrell Museum, said: "We can piece together how these animals fight, and they are likely to first pose at each other and then try to bite each other's heads." ”
A composite diagram of the face of the Tyrannosaurus rex bone, which shows the direction and density of the traces
Image credit: Royal Tyrell Paleontology Museum
Brown cites an example of a T. rex specimen in his study (a 2017 specimen of the upper jawbone unearthed in Dinosaur Provincial Park, Alberta, Canada): "The analysis showed that a series of long scars traversed one side of the jawbone, and we thought that these scars were most likely tooth marks left by another T. rex, and the scars healed and multiplied, forming these raised ridges on the jawbone. ”
Brown noted that Tyrannosaurus rex skull fossils often carry many scars, but no one has ever gathered these traces together for systematic examination studies. So he and his colleagues began to record the occurrence and shape of scars on the skull of the Tyrannosaurus rex, and later extended this research to the fossils of Albertaurus, Tyrannosaurus and Serpentine Female Monster.
Scarred snake-haired banshee upper jawbone.
The icon compares the facial scars of different theropod dinosaurs.
Analysis of scars shows that scars tend to appear on the upper and lower jawbones, some caused by punctures of teeth and others with long scratches. Based on the size of the skull and the location of the bite marks, the researchers compared and analyzed the distance between the teeth to determine the size of the attacker and the injured. "The two sides fighting are usually of similar size, which means that the fight is not a 'David and Goliath' story," Brown said. According to the Bible, King David of Israel defeated the giant Goliath with a weak victory over the strong. The study suggests that this suggests that this type of bite mark is mainly caused by the same kind of fighting.
On the other hand, researchers also found that although facial scars are common, such bite marks cannot be found on juvenile Tyrannosaurus rex fossils. According to the study data, about 50% of the skulls of large Tyrannosaurus rex (but not yet fully sexually mature) have bite marks; about 60% of adult tyrannosaurus rex have bite marks on the skulls.
These data point to an important inference that juvenile Tyrannosaurus rex do not participate in such fights, only those that are old enough to tear each other apart, and that fights only break out between individuals of similar size. In addition, the study also pointed out that although these scars are terrible, these injuries are usually not fatal to Tyrannosaurus rex. This seems to further support the conclusion that fighting is widespread among older Tyrannosaurus rexes.
We know that homosexual rivalry is widespread in nature, and that strife usually occurs after sexual maturity. When animals reach the age to reproduce, they tend to fight with their peers for territory, status, mates, and so on. A similar situation may exist with Tyrannosaurus rex. And the available data suggest that only more than half of the Tyrannosaurus rex of the right age have had such fights, which may be related to gender. "We don't know if only one sex Tyrannosaurus rex was involved in the fight, but this inference is valuable because it relates to the age-old problem of dinosaur sex determination." Brown said.
Caleb Brown is examining fossil jawbones from Albertaurus.
Because dinosaur bones have been buried underground for tens of millions of years, and the soft tissues that indicate their sex have disappeared, determining the sex of dinosaurs has become an almost impossible task. Unless the dinosaur died while pregnant or laying eggs, scientists don't yet have a strong enough judgment to identify the dinosaur's sex. If the study can make further progress, its value is self-evident.