Centipedes are the creepy, extra-leggy relatives of insects and spiders. They are nocturnal, fast-moving predators of anything they can overpower. They are not to be mistaken for millipedes, which are cylindrical, slow-moving scavengers of decaying plant material.
In the United States, there are centipedes that grow to seven inches in length. In more exotic locales, centipedes can get as long as twelve inches. The largest centipedes can catch lizards, frogs, rodents, bats, and small birds. Thankfully, most of the centipedes that we encounter are not that large.
Centipedes are venomous and will readily “bite” when handled. The “fangs” of the centipede are not true fangs because they aren’t part of the mouth; they’re actually legs with venom glands, called forcipules (word of the day). I guess if they’re not using their mouths, then it’s not really biting, but I don’t know what else to call it. Pinching sounds much too harmless for the act, and stinging doesn’t seem quite right but it’s probably more accurate. If you’re being “bit” by one, you probably don’t care how it’s doing it.
Most centipedes are too small to pierce human skin, but the bigger ones are quite capable. The venom is unpleasant - reported to be extremely painful - and can cause a host of symptoms like swelling, chills, and fever, but people rarely die from envenomation. People who are allergic to bees should be cautious around centipedes, as centipede venom can cause anaphylactic shock in sensitive individuals. If you’ve gone into shock before, be sure to carry your epinephrine device, no matter where you go, and no matter how safe you feel. No one ever expects to get bitten or stung, otherwise we would avoid such events.
The two main groups of centipedes that you are likely to encounter are the tropical centipedes and the house centipedes. The tropical centipedes are generally found under rocks, so you may encounter them while gardening. The house centipedes are also commonly found among rocks, but they are unique in that they can live and thrive in human homes. They require high moisture because they are prone to drying out, and so they are often restricted to basements and bathrooms.
House centipedes are quite recognizable with their inordinately long legs. While the legs can make them appear much larger than they really are, they rarely reach 1.5 inches in length. They are tan with three dark stripes running down the length of the body. They are much more reluctant to bite than tropical centipedes, but most homeowners don’t seem to think of that as a positive. Understandably, most homeowners are terrified of these little “monster bugs.”
If you have an abundance of house centipedes indoors, then you likely have an abundance of prey bugs as well. You can find out about your indoor bug ecosystem by using monitors or “sticky traps” and seeing what you catch. A bunch of silverfish, spiders, or crickets means that the centipedes have plenty to eat. Deprive them of food, and you’ll see a lot fewer centipedes.
If centipedes are coming in from outside, then you should do your best to stop them from coming in. Ensure that any cracks are caulked or sealed, especially those that lead into damp, cool areas, like crawl spaces. Sump pumps and basement floor drains should have screens. Dehumidifiers can be used to dry out the air in moist rooms - centipedes hate that.