But they can be pests. Millipedes have a hard shell and have 30 to 90 pairs of legs. Millipedes have two pairs of legs on each body segment, which distinguishes them from centipedes in that centipedes have only one pair of legs per body segment. There are over 1,000 species of millipedes in the United States. The elongated body is rounded and they have no poison claws and will not bite.
Millipedes are scavengers and usually feed on decaying organic matter.
The flattened-bodied centipedes, on the other hand, are predators with many species having pairs of poison claws and use the poison to paralyze their prey, usually small insects. There have been reports of centipedes biting humans, but centipedes are not aggressive and the bite, while a bit painful, is not dangerous. Most common centipedes rarely grow beyond a few inches but can grow up to six inches long. A six-inch long centipede is certainly intimidating and will scare young children and adults alike. Millipedes can grow up to about four inches long.