Millipedes belong to the calls known scientifically as Diplopoda and are a group of arthropods that are characterized by having two pairs of jointed legs on each body segments. Most millipedes have a very elongated cylindrical with more than twenty segments. There are approximately 12,000 species, making Diplopoda the largest class of myriapods. Most millipedes are slow moving detritivores, eating decaying leaves and other dead plant matter. Some eat fungi or suck plant fluids. A very small minority of millipedes are predatory. Millipedes are generally harmless to humans, although some can become household or garden pests. They can be unwanted especially in greenhouses where they can cause severe damage to emergent seedlings. Most millipedes defend themselves with a variety of chemicals secreted from pores along the body. This protects them from being eaten due to their slow movements.Millipedes are most common in temperate forests but are also found in high-altitude alpine environments. Some species live in deserts and some can even be found in caves. Many live under stones, fallen leaves, woodpiles, and other dark, damp locations in forests.