Centipedes and millipedes belong to the arthropod family; they have too many legs to be an insects, and unlike insects, they have numerous body segments. Centipedes and millipedes thrive in gardens and other moist habitats and may come inside your home. The occasional centipede or millipede in your bathroom or basement can be startling, but these pests usually aren't dangerous.
Centipedes are flattened, brownish animals that have several pairs of long legs, usually about 30. They are usually about an inch in length, although their long legs can make them seem much larger. Centipedes paralyse small insects, their primary prey, with the poison claws located behind their head. Centipedes run rapidly when they are disturbed, which may alarm people. Centipedes prefer moist habitats inside the home, such as basements, bathrooms and closets.
Millipedes are rounded animals with lots of small legs, usually less than a hundred. Millipedes are usually brown or black and thrive in moist locations, such as in basements or in decaying organic matter. Millipedes help break down organic matter outside. If they come inside, they usually dry up quickly and die, unless the home is humid. Millipedes usually curl up when disturbed. They don't bite, but some types of millipedes produce a stinging, burning liquid.
Centipedes and millipedes have a lot in common, but it's easy to tell them apart. Centipedes have a flattened appearance, while millipedes are rounder, like worms. Centipedes have one pair of legs per body segment, while millipedes have two or four. Centipedes move rapidly, while millipedes are much slower. In addition, centipedes' last legs extend backwards, while millipedes' last legs do not. Finally, millipedes don't bite. Centipedes may bite, but their bites aren't severe.
Don't worry if you notice occasional centipedes and millipedes in your home. In fact, centipedes may help control populations of other pests, such as flies and cockroaches. If you have a lot of centipedes or millipedes, however, decrease the humidity inside the home and remove moist, decaying matter from outside the home. Sealing cracks in the foundation and using screens in doors and windows may also help keep centipedes and millipedes out of your home. Use chemical pesticides as a last resort.