Did Tyrannosaurus rex Use a Toothbrush?
A number of palaeontologists have suggested that large Tyrannosaurs such as the famous T. rex may have possessed a bacterial bite. An animal with a bacterial bite harbours harmful bacteria in its mouth, gathering their naturally in the teeth serrations and other areas. When this animal attacks and bites a potential prey, the bacteria infect any resulting wounds and serve to further weaken the victim.
Developing the line of thought regarding the possibility of large Theropod dinosaurs having bacterial bites, the question arises regarding how did the big meat-eaters like T.rex clean their teeth?
Tiny Forelimbs of Late Cretaceous Tyrannosaurs
In the case of most Tyrannosaurs, their forelimbs were too small to reach their mouths so the could not have used their claws as tooth picks. The truth is that T.rex probably did not have to clean its teeth, like most reptiles they have a considerable advantage over the mammals when it comes to dentition. Dinosaurs constantly shed their teeth, with new ones growing up from the jawbone to replace old, damaged or worn teeth. This is why when you look at a skull of a T.rex in a museum all the teeth in the jaw are different sizes. The teeth of a T.rex were shaped slightly differently depending on which part of the mouth they come from but the different sizes are due to some teeth being older than others, smaller younger teeth erupting through the jaw.
Larger crocodile species such as the Nile crocodile (Crocodylus niloticus) can have up to 40 sets of teeth in a lifetime. There teeth are conical and not serrated like Tyrannosaurs teeth, the lack of serrations (palaeontologists call these serrations denticles) would make them slightly less likely to have pieces of their last meal stuck to them and therefore less likely to harbour bacteria. As crocodiles gape their teeth are exposed to sunlight and this helps to bleach the teeth and clean them. It is also believed that small birds such as the Nile Plover (Pluvianus aegyptius) may have a symbiotic relationship with the crocodiles. These small birds may give crocs a grooming service – picking off skin parasites and removing pieces of food stuck in the crocodiles jaws.
Did Birds Clean the Teeth of Tyrannosaurus rex?
T.rex lived at a time when the birds had become very well established. There were lots of species of birds around at the end of Cretaceous that are familiar today. Perhaps Tyrannosaurs actively sought out colonies of small birds and gaped with their jaws wide open attracting birds to come over and give them a grooming. Maybe these birds (the brave ones at least) would enter the beast’s huge mouth and remove the shreds of meat left behind from animal’s last meal. This is pure speculation of course, behaviour like this is unlikely to be recorded in the fossil record, but if other animals can develop mutually beneficial relationships – why not dinosaurs as well?