With their huge size, venomous bite and the fantastical connotations of their name, Komodo dragons seem like the stuff of legend.
Now, that status has been elevated further: scientists have discovered that their teeth are coated with a layer of iron that helps keep their serrated edges razor sharp.
It is the first time such a coating has been seen in any animal, and one the researchers describe as “a striking and previously overlooked predatory adaptation in the Komodo dragon”.
The coating was discovered when researchers noticed that the tips and serrated edges of Komodo dragons’ teeth were covered in a layer of orange pigment. On closer inspection, the enamel was found to contain concentrated iron that makes the teeth extra hard and resistant to wear, helping the dragons rip and tear their prey apart.
Komodo dragons are the largest living lizards, growing to more than three metres in length and averaging 80kg in weight. They are native to several Indonesian islands, where they eat almost any prey, ranging from small birds to water buffalo and other Komodo dragons.
Humans have also been killed by the lizards. In 2007, a child on Komodo island died after being attacked by one of the animals. Two years later, a fruit picker on the island was killed by two of the animals after he fell from a tree. In 2010, another Indonesian worker had a narrow escape after punching a Komodo dragon and being released from its jaws.
Indonesian authorities considered banning tourists to the island amid concerns visitors were affecting the animals’ mating habits and causing them to become docile because of food handouts. The species is under threat of extinction owing to habitat destruction and illegal hunting, with only an estimated 3,500 left in the wild.
In the latest study, a team led by researchers at King’s College London used advanced imaging, along with chemical and mechanical analytical techniques, to study teeth taken from various Komodo dragon specimens as well as numerous other living and extinct reptiles, including monitor lizards, crocodiles, alligators and dinosaurs.
The iron coating was most apparent on the Komodo dragon teeth, but similar iron-rich coverings were seen on the teeth of other reptiles. “It looks like it could be a really overlooked but widespread feature of reptile teeth,” said Aaron LeBlanc, a lecturer in dental biosciences at King’s College and lead author of the study.
Komodo dragons’ curved, serrated teeth are a similar shape to those of carnivorous dinosaurs, such as Tyrannosaurus rex. In the study, published in Nature Ecology & Evolution, LaBlanc and his team set out to use the similarity to learn more about how dinosaur teeth might have been used when they were alive.
Although they identified a strengthened iron coating on many of the living reptiles’ teeth, they failed to find evidence of it in any of the dinosaur fossils. Iron coatings might still have been present in carnivorous dinosaurs, the researchers believe. The iron may simply have been lost over time, as suggested by the fact that it could not be found on the fossilised teeth of reptiles closely related to Komodo dragons.
Owen Addison, a professor of oral rehabilitation at King’s College and the senior author of the study, said the discovery could eventually lead to new dental techniques that could be used in humans. “We think there’s an opportunity to use the structure discovered in this work to inform new strategies to regenerate enamel in humans,” he said.
• This article was amended on 24 July 2024. The Komodo dragon is the largest living lizard, but not the “largest living reptile” as an earlier version said.
