Komodo dragons have teeth covered with a layer of iron

Komodo dragons, some of the most ferocious reptiles on Earth, strengthen their teeth with iron crowns, and researchers believe some dinosaurs may have had a similar adaptation.

Komodo dragon (Komodo dragon coati) is endemic to several Indonesian islands and preys on larger animals such as deer, pigs and buffalo; it can grow to three metres in length and weigh up to 150 kilograms.

When Aaron LeBlanc of King’s College London noticed orange serrations on the animal’s teeth, he didn’t initially think they were stains: “It wasn’t until I visited the museum collection and saw all the teeth along the skulls of many Komodo dragon specimens that I became convinced I was looking at a new adaptation for this iconic reptile,” he says.

LeBlanc and his colleagues used high-powered x-rays at a synchrotron facility to examine the surfaces of Komodo dragon teeth and determine the different elements found along the teeth.

“When we mapped the cross-sections of Komodo dragon teeth, we quickly saw that iron was concentrated at the cutting edge and tip of the tooth, but not anywhere else in the tooth,” LeBlanc says, “and this matches up exactly with the orange stains we see on the teeth under a microscope.”

Komodo dragon enamel is incredibly thin compared to human teeth, LeBlanc said: At the serrated edge, the enamel is just 20 micrometers thick, about a quarter of the thickness of a human hair. Human tooth enamel is about 100 times thicker.

The iron coating on Komodo dragon teeth is coated on top of this extremely thin layer of enamel, which the team believes gives the enamel extra strength, protects the serrations as the dragon eats its prey, or acts as a barrier against acidic digestive juices.

Iron is readily available in the environment, especially for large carnivores, and it’s thought that the cells that make enamel change their behavior towards the final layer, producing an iron-rich finish.

Crocodiles and alligators can also concentrate iron in their enamel, but their teeth do not have iron-rich crowns.

The researchers also looked for iron coatings on the dinosaur fossil teeth. They haven’t found evidence yet, but the researchers think that could be because the iron signal was destroyed by fossilization. “We need to look at better preserved dinosaur teeth to be sure,” LeBlanc said.

LeBlanc says his colleagues are intrigued by the potential of these natural materials: “It’s still a long way off, but I can imagine a time when we develop new enamel coatings inspired by nature, perhaps even the Komodo dragon,” he says.