The term "sow bug" is a colloquial term that is used to refer to a specific group of arthropods known as isopods. Commonly found in damp environments, they are often mistaken for insects, but are actually crustaceans that have adapted to a terrestrial lifestyle. There are many other names used to refer to sow bugs, including pillbugs, wood lice, roly-polies, and even "armadillo bugs" due to their tendency to roll up into a ball when threatened. Despite the various names, sow bugs all share similar physical characteristics, including a segmented body, fourteen legs, and a pair of antenna-like structures on their heads.