The Scorpion

Common Name:
Scientific Name:


This common name comes from the order name. Scorpions are nuisance pests, and are also of medical importance because of their stings. Their stings can result in a mild wasp-like sting, which can be complicated by an allergic reaction, and can be fatal in rare instances. Distribution in the United States is primarily in the and southwest and also in the south, with rare occurrences above a line from Baltimore to St. Louis to Salt Lake City to San Francisco. However, in the west they are known as far north as British Columbia. About 70 species occur in the United States.


Adults about 2-4" (20-100 mm) long. Body form characteristic, cephalothorax (fused head and thorax) elongate and dorsally shieldlike (=carapace), abdomen distinctly segmented, anteriorly elongate with last 5 segments taillike, and ending in a sting (=telson) usually curved upward. Cephalothorax with anterior pedipalps large and pincerlike, with small chelicerae between their bases; eyes (ocelli) 0-12, usually 2 dorsal submedian eyes and 1-5 eyes on each front lateral corner; 4 pairs of legs; 1 pair ventral comblike sensory structures (pectines) just posterior of last pair of coxae; and 4 pairs of ventral spiracies. See the pictorial key at the end of this section for help in identification of the more common United States species.


  1. Whipscorpions (order Uropygi) with abdomen oval, segmented, usually with a long whiplike tail but lacking a sting, pedipalps pincerlike, and l st pair legs longest.

  2. Pseudoscorpions (order Pseudoscorpiones) small, usually 3/16"/5mm or less, with flattened, oval bodies, large pincerlike pedipalps, and lack a tail and sting.


  1. Common striped scorpion, Centruroides vittatus (Say); family Buthidas. Adults about 2.3-2.6" (59-67 mm) long. Color yellowish brown to tan, with 2 brown or sometimes reddish brown longitudinal stripes on top of abdomen (except tail), and a dark triangular area on carapace encompasing median and lateral eyes; with 3 pairs of lateral eyes (ocelli); sting with base smooth, lacking an accessory spine (best seen in lateral view); tarsus with 2 spurs at- base; sternum (behind 2nd pair and between 3rd and 4th pair coxae) large, subtriangular; found in South Carolina to Kentucky and west to New Mexico and southward.

  2. Sculptured scorpion, Centruroides scul@turatus Ewing; family Buthidae. Adults about 2-3" (50-76 mm) long. Color with 4 phases, from completely yellowish brown with no markings to striped and very similar to C. vittatus; with 3 pairs of lateral eyes (ocelli); sting base usually with dorsal accessory spine (ventral when tail held above body; best seen in lateral view); tarsus with 2 spurs at base; sternum (behind 2nd pair and between 3rd and 4th pair coxas) large, subtriangular; found in western New Mexico, southern Arizona, in adjacent Mexico, and along the west bank of the Colorado River in California.


Scorpions give birth to living young from the ventral genital opening. These whitish 1 St instar nymphs immediately crawl up a leg onto their mother's back where they remain until their lst molt, which is usually 7-30 days later. They then descend, scatter, and feed. Nymphs average 6 molts before reaching maturity which may take several months to possibly 4 years. Adult coloration is not attained for 2-3 months. Adults may live for several years, 1-6 or more. A summary of biological particulars for C. vittatus follows. Mating takes place in the autumn, and in the late spring to early summer. The gestation period is probably about 8 months. Litter size averages 35 (range 20-47). The Ist nymphal molt occurs 3-7 days after birth. Time required to reach maturity is probably 3-4 years. Parthenogenesis (reproduction without fertilization) occurs in scorpions, although not commonly. Regeneration of lost appendages takes place in scorpions, although sometimes the regenerated part is malformed. The sting of the common striped scorpion causes only temporary local pain, tingling/itching, some localized swelling or tenderness, and sometimes black-and-blue areas; comparable to a wasp or bee sting. In most cases, all signs and symptoms subside within 24 hours. However, some people may develop an allergic response that can be life-threatening.

Stings by the sculptured scorpion can be fatal. Stings are @often very painful and are usually followed by immediate (few minutes to 24 hours) distress, including numbness around the wound which rapidly spreads to the entire extremity; weakness or even paralysis of the injured part; hyperactivity and anxiety; profuse salivation; dizziness; difficulty in speaking and swallowing; respiratory distress; and, in some instances, convulsions. The sting site does not swell or become discolored as it does with less dangerous species. The injected venom is a neurotoxin and if death occurs, it is caused by respiratory paralysis and other complications, usually within 2-20 hours after the sting. There is an antivenom which is effective when administered within 2 hours of the sting, so if the stung person is within the known distribution and/or there is no swelling or discoloration about the sting site, get them to a physician as quickly as possible. The physician should be aware that morphine products, such as Demeral, should be avoided because they have a synergistic effect with the venom of the sculptured scorpion. It is important to note that the victim should be kept calm to minimize absorption of the venom. Use of an ice pack can reduce the pain. . In Arizona, from 1926-1965, the sculptured scorpion caused 75 deaths. Most of the victims were children under the age of 16.


Scorpions are nocturnal feeders. They feed mostly on insects,and spiders, but they can be cannibalistic. After large or active prey is caught in the pedipalps, it is stung repeatedly. The chelicerae then macerate the food into tiny particles which are packed between the coxae of the pedipals and a liquefying secretion is added. The scorpion then ingests the "juice" produced and the resulting dry pellet is discarded. If water is available, they can survive for months without food. During the day, scorpions usually hide either in or beneath something. Outside, it may be a burrow, under a rock, log, or debris, etc. This behavior helps to conserve water loss.

Around structures, scorpions are usually found in crawl spaces and in the attic which they enter via the wall voids. They favor attics with air-conditioning ducts which provide cool temperatures and more harborage; otherwise, they move downward as the temperature increases to above 100'F/38'C. If door thresholds are missing and/or unscreened windows are left open, they may enter directly into the living space. They seek water and can sometimes be found in sinks and bath tubs in the morning because they could not climb out. When sunrise occurs, scorpions seek shelter in the first available harborage which may be in shoes, pants/shirts/jackets on a chair, folded blankets, etc. Ground scorpions, which are those other than Centruroides spp., frequently burrow into children's sand boxes or gravel banks where they can remain buried for up to 6 months.