Komodo Dragons Have Iron-Coated Teeth, Study Finds

Komodo dragons, the largest predatory lizards on Earth, have iron-coated teeth, according to a new study. Researchers also looked at other reptiles and found that tooth enamel containing iron tips may be widespread, they reported last week in the journal Nature Ecology.

But the newly discovered feature was most striking in Komodo dragons—their chompers have an orange, iron-enriched coating on their serrations and tips. The adaptation could help maintain the sharpness of Komodo dragon teeth, which only have a thin layer of enamel.

“If they didn’t have this iron coating, I’m sure the enamel on the cutting edges would wear away very quickly and the tooth would dull,” Aaron LeBlanc, first author of the study and a paleontologist at King’s College London, tells CNN’s Jack Guy. “That’s not very good for an animal that relies on having these razor-blade sharp teeth to slice through meat.”

“[The study] tells us that reptiles still hold a lot of surprises,” LeBlanc adds to National Geographic’s Alice Sun. “It’s leading down a whole new avenue of research.”

Komodo dragons have long tails, sturdy limbs and yellow, forked tongues, and they’re one of the few reptile species with a venomous bite. They typically weigh around 154 pounds, though the largest recorded dragon stretched more than 10 feet long and weighed 366 pounds.

The apex predators eat just about any kind of meat and use their serrated, curved and blade-shaped teeth to tear through animal flesh. Despite their importance, Komodo dragons’ teeth, as well as those of dinosaurs, only evolved a thin layer of enamel. The largest predatory dinosaurs had just 10 to 20 percent the enamel thickness of a human tooth.

While enamel is important for humans, scientists suspected the teeth of Komodo dragons and dinosaurs had another feature that made them specialized for ripping apart tissue. After all, multiple animals evolved teeth like this, and Komodo dragon teeth are able to hold up despite their heavy use during eating.

The authors of the new paper were using Komodo dragons as a proxy to study why dinosaur teeth may have been well-suited to eating meat, according to Science News’ Erin Garcia de Jesús.

Under a microscope, they noticed orange-colored lines along Komodo dragons’ tooth crown tips and serrations—and because developing teeth showed the same hue, the coloration didn’t seem to be a result of staining from feeding.

“I saw it many times before I actually believed it,” LeBlanc tells CNN.

“Only after visiting museum collections and looking at all of the teeth along the skulls of many Komodo dragon specimens was I convinced that I was looking at a novel adaptation in these iconic reptiles,” he says to New Scientist’s James Woodford.

X-ray imaging revealed the orange pigmentation was iron, coating the teeth in a thin layer.

“It’s interesting that the serrations have the majority of the iron, which suggests that they’re reinforced,” study co-author Domenic D’Amore, a paleontologist at Daemen University, tells National Geographic. “Because they’re particularly important” for tearing prey to pieces.

Additionally, while the thin iron coating could keep Komodo dragons’ teeth sharp, it also may protect them from digestive acids.

Researchers had previously observed iron in the enamel of other animals, including beavers, shrews, some fish and salamanders, but it had never been reported in a carnivorous reptile. Its function in these animals has also remained elusive, but the new findings support the idea that the iron could strengthen their teeth.

The study also marks the first time an iron coating specifically along the cutting edge of a tooth has been observed in any animal—and the team found evidence of similar orange cutting edges in other species, though to a lesser degree. The list includes several other kinds of monitor lizards, alligators and crocodiles, suggesting the adaptation could be widespread in reptile teeth.

Though the researchers didn’t find evidence of iron coatings on dinosaur teeth, that isn’t surprising, since fossilization could have wiped away the mineral, Lisa Whitenack, a paleobiologist at Allegheny College who did not contribute to the findings, tells Science’s Jason Bittel.

Will Sullivan | | READ MORE

Will Sullivan is a science writer based in Washington, D.C. His work has appeared in Inside Science and NOVA Next.