Content Updated: January 05, 2026

Key takeaways

  • Millipedes are arthropods with segmented bodies, jointed legs, and exoskeletons.
  • Hundreds of tiny legs help millipedes move slowly but steadily through soil and leaf litter.
  • By feeding on dead plants, millipedes help maintain healthy and balanced ecosystems.
  • Millipedes prefer damp habitats and rarely survive long indoors, so they are usually temporary visitors.

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Millipedes are those long, black bugs with what seems like a million tiny legs that you see crawling in your basement or garage. They won't bite you, but they can emit a smelly fluid that might irritate your eyes or skin. Though they're not harmful to your family, they can be a nuisance in large numbers. Here are more millipede facts to help you better understand these many-legged creatures.

The evolution of millipedes

Millipedes might look like worms with lots of legs, but they’re actually arthropods with jointed legs, segmented bodies, and a hard exoskeleton. Milipede facts show that they’ve been around for hundreds of millions of years, with some of their early relatives among the first animals to walk on land. Fossils show that some of the earliest millipede-like creatures were huge, measuring up to six feet long and one and a half feet wide.1

TMX Millipede crawling

A thousand legs and counting

Despite their name, millipedes don’t actually have a thousand legs. Most have a few dozen to a few hundred, while the record-setter tops out at over 1,300 legs. Milipedes are born with only a handful of legs and gain more with each molt. Their wave-like millipede leg movement is one of the things that makes them so fascinating and slightly creepy to watch.

Millipedes have simple eyes, and some species have multiple hearts running along their long bodies. Another interesting fact about millipedes is that they can regrow lost legs while they’re still developing. They move pretty slowly, partly because coordinating that many limbs is no small task.

Millipedes' role in the ecosystem

Millipedes are nature’s recyclers. They eat decaying leaves and plants, helping break down organic material much faster than it would on its own. This process returns nutrients into the soil and keeps our ecosystems running smoothly.

These anthropods can come in all sizes, from tiny species just a quarter inch long to giant ones reaching up to 15 inches. Regardless of size, each one helps maintain a healthy forest floor, which is just one of many fun facts about millipedes that show how important they really are.

A millipede's favorite place

Millipedes love damp environments because they need moisture to survive. Indoors, this could mean basements, crawl spaces, bathrooms, garages, or any other area where humidity builds up. They often wander indoors during long stretches of rain or drought, but usually don’t survive more than a day or two inside due to dry air.

Outside, a typical millipede habitat includes mulch, compost, leaf piles, or spaces under rocks and logs. These sheltered, moist spots help them stay hydrated and close to their favorite food source: decaying plants.

TMX millipede outside crawling

Millipedes as pets

Some people keep millipedes as pets, especially the larger, exotic species. They’re quiet, simple to care for, and surprisingly gentle. They won’t bite or scratch, and their slow movements make them easy to handle.

They’re not considered as intelligent as other pets, but they are typically calm and docile. Most species aren’t dangerous to humans, and while people ask are millipedes poisonous, their defensive fluids usually only cause mild skin irritation.

Millipedes vs. centipedes

Even though many people group centipedes and millipedes together, they’re very different. Millipedes have round bodies and two pairs of legs per segment, while centipedes are flatter with one pair per segment. Centipedes are carnivores and much faster; millipedes are slow-moving plant eaters that curl into a spiral for protection. If you need millipede control or help with other unsightly pests, Terminix can help you identify them and keep them outside where they belong.

1Milipede fact about an ancient millipede growing several feet long, sourced from the National Park Service.