Iron is a cornerstone of life on Earth, essential to the survival of all oxygen-consuming organisms. It’s an element we carry within us, quietly yet crucially sustaining our bodies. Roughly 4 grams of iron circulate through your bloodstream right now, enabling your circulatory system to function properly by aiding in the transport of oxygen to cells throughout your body. Without iron, our bodies would be unable to produce hemoglobin, the protein in red blood cells responsible for carrying oxygen—a task vital to life as we know it.
However, in the grand tapestry of nature, iron does far more than just keep us alive. Several species have evolved to use iron in ways that go beyond mere survival, turning this common element into a powerful tool for protection, hunting, and more.
Scorpions, crabs, worms and other creatures also have metal atoms in their claws, jaws and fangs. These deposits are an evolutionary feat of engineering; they make the structures significantly stronger and longer lasting. Rather than occurring in organized clusters of atoms—a shiny strip of tin foil is one example—they are single atoms held in place by non-metals. This is part of the reason that no one discovered these deposits until about 30 years ago: it is difficult to detect a single atom unless you are specifically looking for it. Moreover, the metals—mainly iron, copper, manganese and zinc—are present only in very small parts of the animal.
Here’s a look at some of the incredible ways iron is utilized in the natural world.
The Scaly Foot Gastropod: Iron-Clad Armor of the Deep
One of the most fascinating examples is Chrysomallon squamiferum, commonly known as the scaly foot gastropod. This deep-sea snail, found near hydrothermal vents, has developed an extraordinary defense mechanism. The external part of its foot is covered with a thick armor of scales that are reinforced with iron sulfide. Even more impressively, the outer layer of its shell is also coated in this iron compound, making the scaly foot gastropod the only known animal to use iron in such a direct, structural way. This iron armor provides the snail with protection from predators and the harsh environment of the deep sea.
Komodo Dragons: Razor-Sharp Iron Teeth
Komodo dragons, the giant lizards of Indonesia, are already fearsome predators with their massive size and potent venom. Recent discoveries, however, have revealed an additional weapon in their arsenal—iron-coated teeth. The iron in their teeth keeps them razor-sharp and highly resistant to wear, ensuring that their bites remain lethal over a long lifespan. This iron coating is a key factor in the Komodo dragon’s ability to tear through flesh with ease, making it one of the most efficient predators on the planet.
North American Beaver: Iron-Hardened Teeth
The North American beaver also employs iron in an extraordinary way. The enamel of their teeth is fortified with iron, making them much stronger than human teeth. This iron infusion gives beaver teeth a bright, rust-orange color and the durability needed to chew through tough wood, an essential task for building their dams and lodges. The iron-hardened enamel allows beavers to efficiently cut down trees and process wood, activities central to their survival and ecological impact.
The Hidden Power of Iron in Nature
These remarkable examples highlight the versatility and importance of iron in the natural world. While we often think of iron as something simple and utilitarian, these species show us that iron can be adapted for extraordinary purposes. Whether it’s providing life-sustaining oxygen to our cells, reinforcing a deep-sea snail’s armor, keeping a predator’s teeth sharp, or strengthening a beaver’s bite, iron is an element that powers life in ways we’re only beginning to understand.
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