Once upon a time, truly gigantic lizards lived on Earth. For example, the dinosaurs Giraffatitan brancai reached 12 meters in height, and their weight was 30-60 tons. However, 65-66 million years ago, a catastrophe occurred, as a result of which all non-avian dinosaurs died. Currently, the largest lizards are Komodo dragons, which grow up to four meters in length and weigh more than 100 kilograms. And although they are much smaller than ancient reptiles, in their lifestyle and even appearance they strongly resemble them, for example, much more than crocodiles. Therefore, scientists even study these animals to learn more about dinosaurs. For example, a recent study showed that extinct lizards could have iron teeth, which Komodo dragons now have.
Komodo dragons are the largest lizards on Earth. Photo source: medium.com
Giant monitor lizards have teeth made of iron
The Komodo dragon, also known as the giant Indonesian monitor lizard or Komodo dragon, lives on the Indonesian islands, but its homeland is Australia. Previously, it was more common, and lived not only in Australia, but also on the island of Java. The oldest remains of this animal are 3.8 million years old. Of course, these monitor lizards did not live to see dinosaurs, but they are still a very ancient species.
Komodo dragons are the top predators in their ecosystem. They hunt a wide variety of animals, from small reptiles and birds to horses and even Asian buffalo. They do not intersect with other land predators. Komodo dragons' main weapon is their sharp, powerful teeth. Like many carnivorous dinosaurs, they are serrated and curved backwards.
Komodo dragons hunt large animals. Photo source: dzen.ru
When a monitor lizard attacks its prey, it sinks its teeth deep into the flesh, then lunges back and moves its powerful neck. In this way, the reptile inflicts fatal lacerated wounds. It would seem that with age, these animals' teeth should become duller, but this does not happen – the monitor lizard's teeth always remain razor sharp.
Scientists at King's College London have managed to unravel their secret. As it turns out, the cutting edges and tips of the teeth are literally covered in iron, which is why they are orange.
All reptiles have iron in their mouths
To understand the chemical and structural composition of Komodo dragon teeth, scientists turned to museums that had the remains of these animals. Among them were the teeth of a 15-year-old Komodo dragon that lived in a zoo in London.
The teeth of the Komodo dragon are coated with iron. Photo credit: www.kcl.ac.uk
A study using advanced imaging techniques and chemical analysis has shown that the iron in the teeth of Komodo dragons is concentrated in a thin coating on the serrations and tips of the teeth. This protective metallic layer protects the serrated edges and, as mentioned above, allows them to always remain sharp. The researchers report this in the journal Nature Ecology & Evolution.
It should be said that scientists had previously known that many reptiles have a certain amount of iron in their teeth. However, other species of monitor lizards and crocodiles have very little of it, so it does not even affect the appearance of the teeth.
Did monitor lizards get their teeth from dinosaurs?
It can be assumed that iron accumulates in the teeth of monitor lizards as a result of some special diet. However, studies have shown that even small monitor lizards, whose teeth are still hidden in the gums, already have characteristic “metal tips”. This means that the metal coating is an evolutionary feature of these animals. Moreover, scientists assume that carnivorous dinosaurs once had the same metal teeth.
Dinosaurs may have had similar iron-coated teeth. Photo source: www.kcl.ac.uk
Unfortunately, current technology does not allow us to understand whether ancient reptile teeth contained iron before they fossilized. The chemical changes that occur as a result of fossilization do not allow iron to be preserved.
However, scientists have found that large carnivorous dinosaurs, such as tyrannosaurs, had different enamel structures on the cutting edges of their teeth. That is, while Komodo dragons changed the chemical composition of their teeth, large reptiles changed the structure of their tooth enamel to maintain a sharp cutting edge. This feature was not found in smaller dinosaurs, so it is quite possible that their teeth really were like those of monitor lizards.
Komodo dragons have a glandular coating from a very early age. Photo source: herpeto-volga.ru
It must be said that the latter had to have “metal tips” on their teeth. The fact is that the tooth enamel of these animals is very thin in itself, so it needed to be strengthened. Accordingly, individuals with glandular additives received an evolutionary advantage. In addition, teeth with such a coating are most likely more resistant to acid, which is also important, since monitor lizards constantly regurgitate wool, horns and other waste that they cannot digest.
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Unfortunately, Komodo dragons are currently endangered. As the researchers note, the discovery they made will not only strengthen the understanding of how dinosaurs could live, but will also help to better understand the monitor lizards themselves. Perhaps this will make it possible to increase the effectiveness of measures to protect giant lizards from extinction.