Elateridae or click beetles (or "typical click beetles" to distinguish them from the related families Cerophytidae and Eucnemidae, which are also capable of clicking) are a family of beetles. Other names include elaters, snapping beetles, spring beetles or skipjacks. This family was defined by William Elford Leach (1790–1836) in 1815. They are a cosmopolitan beetle family characterized by the unusual click mechanism they possess. There are a few other families of Elateroidea in which a few members have the same mechanism, but most elaterid subfamilies can click. A spine on the prosternum can be snapped into a corresponding notch on the mesosternum, producing a violent "click" that can bounce the beetle into the air. The evolutionary purpose of this click is debated: hypotheses include that the clicking noise deters predators or is used for communication, or that the click may allow the beetle to "pop" out of the subtrate in which it is pupating. It is unlikely that the click is used for avoiding predators as it does not carry the beetle very far (<50cm), and in practice click beetles usually play dead or flee normally. There are about 9300 known species worldwide, and 965 valid species in North America.