Woodlouse

A woodlouse (plural woodlice), also known by many common names (see below), is an isopod crustacean with a rigid, segmented, long exoskeleton and fourteen jointed limbs. Woodlice form the suborder Oniscidea within the order Isopoda, with over 5,000 known species.

Woodlice in the genus Armadillidium and in the family Armadillidae can roll up into an almost perfect sphere as a defensive mechanism, hence some of the common names such as pill bug or roly-poly. Most woodlice, however, cannot do this.

Common names

Common names for woodlice vary throughout the English-speaking world. A number of common names make reference to the fact that some species of woodlice can roll up into a ball. Other names compare the woodlouse to a pig.

Names include: