North American Millipedes Identification Guide
Narceus americanus
North American millipedes are large, slow-moving bugs with round bodies and many legs. They live in damp places and sometimes enter homes when it gets too wet or dry outside.
Taxonomy
North American Millipedes Coloration
Common color patterns to help identify north american millipedes
North American Millipedes
Seasonal Activity
When north american millipedes are most active throughout the year
Where North American Millipedes Are Found
Hover over states to see their names. Green regions indicate where north american millipedes have been reported.
North American Millipede Identification Guide
Physical Characteristics
The North American millipede (Narceus americanus) is also called the American giant millipede or iron worm. It is one of the largest millipedes in North America. Adults are 2 to 4 inches long, and some can reach 4.5 inches. They have round, segmented bodies that are dark brown to black. Many have red or purple tones along their sides.
Each body segment has two pairs of short legs. This gives them anywhere from 80 to over 400 legs, depending on their age. Unlike centipedes, which are flat and fast, millipedes have round bodies and move slowly. Their legs move in a wave-like pattern.
When scared, North American millipedes curl into a tight coil. This protects their soft belly. They also give off defensive chemicals that keep predators away. Their hard outer shell adds extra protection.
How to Tell Millipedes from Similar Pests
People often mix up millipedes with other bugs that have many legs:
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House Centipedes: House centipedes have flat bodies, very long legs, and move fast. They hunt other insects. Millipedes move slowly, have short legs, and eat rotting plants.
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Centipedes: Centipedes have one pair of legs per segment and flat bodies. They hunt prey. Millipedes have two pairs of legs per segment and round bodies. They eat dead plants.
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Greenhouse Millipedes: These smaller millipedes (Oxidus gracilis) are under 1 inch long. They are dark brown with pale edges. North American millipedes are much larger.
North American Millipede Behavior and Biology
Where They Live
North American millipedes are native to the eastern United States and parts of Canada. They help break down dead leaves and return nutrients to the soil. They prefer forests but also live well in yards and gardens.
These millipedes need damp places because they dry out quickly. You can find them:
- Under leaf piles and mulch
- Beneath rotting logs and bark
- In compost piles
- Under rocks and stepping stones
- In crawl spaces and damp basements
- Near plants with thick mulch
They come out mostly at night and when it rains. On hot, dry days, they hide deep in the soil to stay moist.
What They Eat
North American millipedes only eat dead plant matter. Their diet includes:
- Fallen leaves
- Rotting wood and bark
- Dead plant material
- Fungi
- Sometimes rotting fruit or vegetables
They do not eat living plants, wood in your home, clothes, or food. This makes them different from pests that cause real damage.
Life Cycle
Female millipedes lay eggs in moist soil. They may lay several hundred eggs over their lifetime. The eggs hatch into tiny millipedes with just a few body segments.
Young millipedes shed their skin many times as they grow. Each time, they add more body segments and legs. It takes 2 to 5 years for them to become adults. Adults can live 1 to 2 more years. Some millipedes live 7 years or longer.
How They Defend Themselves
When scared, North American millipedes protect themselves in several ways:
- Curling up: They roll into a tight coil to protect their soft underside
- Releasing chemicals: They give off smelly fluids from glands on their body
- Playing dead: Some stay still when touched
The fluids smell like almonds and can stain your skin brown. They usually do not harm people, but some may get mild skin redness. If this happens, wash the area with soap and water. See a doctor if you have a strong reaction.
How We Treat for North American Millipedes
Our millipede treatment targets the pests and fixes the conditions that bring them to your home.
Inside Your Home
Our technician checks inside your home for millipedes. We focus on:
- Basements and corners along walls
- Crawl spaces
- Damp areas
- Cracks and gaps where they get in
We apply treatment along baseboards and other spots where millipedes show up. This creates a barrier that keeps them out and pushes existing ones away.
Outside Your Home
We also check the outside of your home. We look at:
- Mulch beds near the foundation
- Leaf piles and debris
- Shaded, damp areas along the foundation
- Cracks in the foundation
- Basement window wells
For bigger problems, we apply granular treatment around the foundation and mulch beds. This stops millipedes before they reach your home.
Tips to Keep Millipedes Away
Since millipedes need moisture and rotting plants, changing their habitat helps keep them out for good:
- Keep mulch under 2 inches deep and away from your foundation
- Clear leaves, dead plants, and rotting wood from around your home
- Fix drainage so water does not pool near the foundation
- Seal cracks around doors, windows, and the foundation
- Use a dehumidifier in your basement or crawl space
Ongoing Protection
Our tri-annual pest control plan (three visits per year) keeps millipedes away. We treat in spring and fall when they move around the most. If you see millipedes between visits, we come back at no extra cost.
References
Other Millipedes
Explore other species in the millipedes family
Commonly Confused With
North American Millipedes are often mistaken for these similar pests
Where North American Millipedes Are Found
Hover over states to see their names. Green regions indicate where north american millipedes have been reported.
Common Questions about North American Millipedes
Are North American millipedes dangerous?
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No, millipedes are not dangerous. They do not bite or sting. When scared, they may release a fluid that can cause mild skin redness or staining. Wash the area with soap and water. See a doctor if you have a strong reaction. This is not medical advice.
Why are millipedes suddenly appearing in my house?
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Millipedes come inside when it gets too wet or too dry outside. Heavy rain or drought makes them move. They get in through cracks in the foundation, gaps around doors, and basement windows.
How many legs does a North American millipede have?
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Millipedes have between 80 and 400 legs. The name means 'thousand feet,' but they never have that many. Each body segment has two pairs of legs. They add more segments as they grow.
Will millipedes damage my home or belongings?
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No, millipedes do not damage homes, eat clothes, or get into food. They only eat dead plants. The main problem is that they are a nuisance. Some types can stain surfaces with their defensive fluids.
How long do millipedes live indoors?
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Millipedes cannot live long inside. They need damp air and rotting plants to survive. In dry homes, they usually die in a few days. Finding dead millipedes means they came in looking for moisture but did not find it.
What attracts millipedes to my property?
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Millipedes like moisture and rotting plants. Thick mulch, leaf piles, compost, rotting wood, and poor drainage bring them in. Cracks in the foundation, especially in shaded or damp spots, let them enter.
Can millipedes infest my house?
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Millipedes cannot breed or live long inside your home. What looks like an infestation is really a large group moving at once due to weather. This is temporary. Fixing the things that attract them will prevent future problems.
With five years of hands-on experience in the pest control industry, George Schulz is a registered technician with the Virginia Pest Management Association and a proud third-generation professional in a family business that's been protecting homes for over 57 years. He manages and trains a team of service pros while also leading internal research efforts—recently spearheading a deep-dive review of thousands of documents on pest control materials to hand-pick the most kid and pet friendly, most effective solutions tailored specifically for homes in the DC metro area.