How did the mighty sabre-tooth tiger keep its large teeth from breaking off? According to scientists, it could well be that the baby teeth played an important role in this.
Saber-tooth tiger skulls have been harvested for quite a few years now Smilodon fatalis excavated from the La Brea Tar Pits, near Los Angeles. Scientists have now collected more than 2,000 skulls from this site. However, some of these skulls turned out to be slightly different from the rest: they still had their ‘baby teeth’. New research shows that there was an important reason for this: it is likely that the sabre-tooth tiger kept its baby teeth during ‘puberty’, in order to protect and guide the growth of the permanent saber teeth.
Scientist Jack Tseng contributed to the research. He says: “The new research confirms an idea that I, together with other scientists, had suggested a number of years ago. For example, we suspected that the growth of the saber teeth was timed in such a way that it made a ‘double tooth’ phase possible. The idea here is that the baby teeth fully emerge first. The moment these are ‘finished’, the growth of the permanent saber teeth begins. These permanent saber teeth eventually knock the baby teeth out of place. However, the entire growth process of these permanent saber teeth takes about 30 months. We therefore had the idea that the baby teeth could serve as a ‘shield’ during this time.” The research has been published in the journal The Anatomical Record.
Beam Theory
For the study, the scientists started with the skulls of sabre-tooth tigers that had both baby teeth and permanent teeth. Computer models were made based on these skulls, after which the experimentation could really begin. The computer models were used to figure out how much lateral tension the still-growing permanent saber teeth could ultimately handle. The researchers used this beam theory. Tsang explains what that means: “According to the beam theory a blade-shaped structure is weaker when you push it sideways in one direction.” In essence falls beam theory can therefore also be used on a kitchen knife by pressing the flat side onto a surface. In this way, the blade of the kitchen knife will be less ‘strong’ – and therefore bend more – than when you press the sharp side of the knife on a surface.
Tsang continues: “Scientists are seeing this aspect of beam theory has therefore been seen as a disadvantage for the sabre-tooth tiger for some time. Any way you look at it, it’s likely that the saber teeth couldn’t handle very much lateral force.” The research shows that saber teeth become more flexible as their length increases. This makes them easier to break. During the research, Tsang discovered that the baby teeth can help significantly by adding extra thickness to the whole, making the (still growing) permanent saber teeth more resistant to sideways tension.
Insurance
The results of the research are significant, because they can ultimately solve part of the saber-tooth puzzle. Despite that, Tsang still has a lot of questions. He says: “The ‘double tooth’ phase will likely influence the way we view the tooth growth process. This is because we now know that sabre-tooth tigers had a kind of ‘insurance’, so to speak, that could give them more protection. This probably allowed ‘adolescent’ sabre-tooth tigers to learn how to use their saber teeth without accidentally breaking them. This introduces more nuance into the way we think about the sabre-tooth tiger’s hunting behavior, although some questions remain unanswered.”
By the way, the researchers certainly do not want to claim that the enormous teeth of the sabre-tooth tiger – partly because of the supporting baby teeth – were untouchable. Sometimes the teeth simply broke. For example, previous research revealed that sabre-tooth tigers’ teeth broke noticeably often during periods of food scarcity. In that study, the scientists suggested that this was likely because sabre-tooth tigers had to hunt for other sources of food.
