|any lamellicorn beetle of the family Lucanidae, the males of which have large branched mandibles|
any of some 900 species of beetles (insect order Coleoptera) in which the mandibles (jaws) are greatly developed in the male and resemble the antlers of a stag. In many species the elaborately branched and toothed mandibles may be as long as the beetle itself. If handled carelessly, their pinch can draw blood from a person. In some cases, however, the mandibles are large enough to be a handicap to the beetle's movement
Learn more about stag beetle with a free trial on Britannica.com.