By Bill Lawyer

Winter is often seen as a time when most of the wild insects are gone, either hibernating, or, in the case of monarch butterflies, migrating south.

But in fact, this is not the case.

If your house is anything like mine (but probably a lot newer), and if you venture down to the basement, you’ll find that some invertebrate “critters” have not gone south but rather come in from the cold.

You might use this fact as an excuse to stay out of the basement or closets, crawl spaces, and the like. Most people have no desire to encounter a crawling critter moving across their basement floor or wall at any speed.

But if you’re adventurous, you can go peek in the nooks and crannies to see what’s going on down there. For the most part, these are not noisy intruders, and you rarely see them unless to turn on a light in a dark room.

Some of the more fascinating and harmless lodgers you are likely to encounter are the millipedes. They come marching in, but their many feet make no noise that we can hear.

Fortunately, millipedes are not predatory, and in many other ways are slow and harmless compared to such things as the speedy, spooky centipedes. (I’ve often wondered why no children have devised centipede Halloween costumes.)

While worldwide there are over 12,000 species of millipedes, the only one we’re likely to encounter in our nooks and crannies is the American Giant (Narceus americanus).

While by definition a millipede means 1,000 legs, all scientists consulted agree that most species have a few hundred or less. The most ever officially encountered was a species found in the Northwest with 750 legs. Curiously, centipedes can have 50 to 350 legs, and never 100 due to always having an odd number of pairs.

The North American centipedes are about four inches long, but in tropical climates some species get as large as 15 inches The largest one I’ve seen in the wild was a yellow and black striped species in Puerto Rico, about 7 inches in length.

Millipedes have the ability to roll up into a ball for protection, the way that pill bugs do. And like skunks, millipedes can produce a nasty smelling chemical that discourages would-be predators.

While millipedes look somewhat like worms, they are not. Except for the first few segments that have one or no legs, most of their bodies are divided into segments with each one having two pairs of legs.

Like many invertebrates, millipedes have hardened plates on their segments for protection. Also like most invertebrates (cockroaches, for example), they are well adapted to the changes to the earth caused by climate change. The warmer and more moist the environment, the better they thrive.

Scientists have determined that millipedes were among the very first animals to evolve to live on land.

They reproduce using spermatophores, which are either taken by females directly from the males or collected from spermatophores deposited on or under the ground.

The females make nests and lay up to 100 eggs, which hatch in about a month. But because they have a variety of enemies, the overall population of millipedes in the environment is fairly stable.

While not recommended for everyone, a number of people keep millipedes as pets, generally the African Giant millipede, which grows to be about 10 inches long.

Meanwhile, be nice to millipedes — they help break down leaf litter and other vegetative matter, which provides free mulching and decomposing services right in our backyards.


A North American millipede rolled up in protective mode.