Giant American Millipedes and Their Remarkable Life

The North American continent is home to a diverse array of invertebrates, with the giant American millipede being one of them. This millipede boasts an impressive number of legs and a unique defense mechanism. Let’s take a closer look at the Giant American Millipede to see what makes it so special, including how it lives, its behaviors, and why it’s important for nature.

Giant American Millipede
Scientific name: Narceus americanus
Phylum: Arthropoda
Class: Diplopoda
Order: Spirobolida
Family: Spirobolidae
Genus: Narceus

They’re big

If you’re a fan of giant African millipedes, you might enjoy the giant American millipede too. Also called the worm millipede or iron worm, this sizable critter is found in eastern North America.

It’s easy to spot with its dark body adorned with red or red-orange bands on each segment. Even its legs and feet sport the same reddish-orange color. Occasionally, you might come across a rare albino version, which is quite stunning because pigment-less creatures are exceptionally uncommon among invertebrates.

Different types of North American millipedes vary in the number and look of their legs, body segments, and color. Usually, males have longer legs and antennae compared to females.

These millipedes have a tubular body that can reach the size of 4 inches (about 10 cm) in length. They have stink glands called ozadenes on their bodies, which release a smelly substance when they feel threatened. However, unlike some millipedes, they don’t emit toxic hydrogen cyanide.


As the name suggests, giant American millipedes live mainly in North America. They have a wide range, spreading across many states east of the Mississippi River and nine states to the west, including Canada.

These millipedes mostly live in forests, farms, and sometimes in urban areas. You can often find them under rocks, dead trees, or in piles of wet leaves, where they live in the layer between the soil and litter. Sometimes, they even hang out in moist animal remains.

Giant American Millipede Diet

Millipedes like to eat rotting leaves, roots, and wood, especially if they have bacteria and fungi, which make the nutrients easier to get and the food tastier. Sometimes they’ll nibble on live plants, but they almost never eat animals.

These species are eaten by many predators, such as ants, skunks, beetles, opossums, lizards, birds, moles, salamanders, scorpions, shrews, raccoons, and turtles.

To protect themselves from predators, these millipedes squirt out a liquid with a lot of benzoquinones, which can burn your skin and make it change color. However, they’re not poisonous to humans. They also curl up into a tight ball to show off their hard shell, kind of like wearing armor.


Giant American millipedes are nocturnal and solitary animals. When it gets cold in the winter, they hibernate. To keep from drying out, these species shed their old skin in damp areas to soak up water through their outer layer.

These millipedes can move around using their many pairs of legs. They can walk in different directions – forward, backward, and sideways. They can even dig into the soil.

Giant American Millipede defensive

Like other millipede species, they use their antennas to explore their surroundings. These antennae help them taste food, smell scents, feel things, and even find water. They also have special organs, called Tömösváry organs, near the base of their antennae, which help them measure humidity and might help them sense chemicals in the air.


The breeding season of these North American millipedes takes place in the spring and early summer. During this time, males create a silk thread and release pheromones to attract females. Their mating behavior is quite similar to that of other species, which you can know more details here. Some females mate just once, using the sperm they store to fertilize all the eggs they lay, while others mate multiple times with different males.

Two Giant American Millipedes

Unlike many other millipedes that lay hundreds of eggs, the female giant American millipede is said to lay just one egg at a time. She carefully prepares a nest made of chewed leaves and excrement, then wraps herself around the egg to keep it warm. After a few weeks, the egg hatches, and the mother’s role ends there. It takes young millipedes 1-2 years to molt and grow into adults, with males usually maturing before females.

The lifespan of giant American millipedes is quite long. The longest one of these millipedes has been known to live for is 11 years.



Animal Facts 276

We are passionate animal enthusiasts with over a decade of experience studying animals. With a degree in zoology and conservation biology, we've contributed to various research and conservation projects. We're excited to bring you engaging content that highlights the wonders of the animal kingdom. We aim to inspire others to appreciate and protect wildlife through informative content grounded in expertise and passion. Join us as we delve into the captivating world of animals and discover the incredible stories they have to tell.

Leave a Comment