It is estimated that there are as many as 1,500 different species of scorpions worldwide. The U.S. is home to at least 40 species, found primarily in the southern and western states. Stings can cause local pain and swelling and do not usually warrant medical treatment. However, one species in the U.S. is regarded as medically significant: the Centruroides sculpturatus, better known as the bark scorpion. Bark scorpions can be distinguished from other less dangerous species by their more slender tail segments and pincers and by locating a tubercle, (small bump), at the base of their stingers.
Bark scorpions are most commonly found in Arizona, isolated colonies have also been reported in Clark County, Nevada; parts of Texas; Western New Mexico and California, and around Lake Mead. The bark scorpion is named because of its frequent association with trees, it can be found in abundance even in established residential areas. These scorpions only grow to about two inches at maturity. They have four pairs of legs and a pair of pedipalps, or front limbs with pincers, that are used for restraining prey, as well as for defense.
Most people are stung by scorpions inside or around their own homes. Scorpions inject venom from a stinger on their tail and not by biting their victims. Undisturbed scorpions will spend the daylight hours in dark cracks and crevices, in woodpiles or under debris on the ground. Most stings occur at night when scorpions venture into human habitat in search of insect prey. Small cracks and breeches in homes, especially around doors and windows provide easy entry for these comparatively small scorpions. Once indoors they seek out moist and cool areas such as sink areas, bathtubs and laundry areas. With flat and elongated bodies, bark scorpion are avid climbers up vertical surfaces in our homes, and also across ceilings. While practicing what is called “negative geotaxis”, or hanging upside-down, scorpions can drop from the ceiling and land in some unsuspected locations, like a fruit bowl or in an infant’s crib. Failing to turn on lights before entering a dark room can increase our chances of encountering a scorpion, and thus of getting stung.