Scarab, name for members of a large family of heavy-bodied, oval beetles (the Scarabaeidae), with about 30,000 species distributed throughout most of the world and over 1,200 in North America. North American scarab beetles range in length from less than 1-2 in. to more than 2 in. (5–50 mm); members of some tropical species grow several inches long. Many scarab beetles are brightly colored and many are iridescent.