Scorpion Identification

Scorpion Identification

Scorpions are nocturnal, predatory animals that feed on a variety of insects, spiders, centipedes, and other scorpions. Large scorpions occasionally feed on vertebrates, such as small lizards, snakes, and mice. Most scorpions live in warm, dry climates and many of the species found in North America occur in Arizona, adjacent areas of California, and parts of New Mexico. Of the 70 or so species found in North America, only one, the bark scorpion, Centruroides exilicauda (formerly called C. sculpturatus), is considered dangerous to people.

IDENTIFICATION
Scorpions are easily distinguished by their crablike appearance, with a pair of pincers, four pairs of legs, and a long, segmented tail ending with an enlarged segment bearing a stinger. Although they have two eyes in the center of the head and usually from two to five more along the margin on each side, they do not see well and depend on touch. When running, they hold their pincers outstretched and the posterior end of the abdomen is usually curved upward. Scorpions that hide under stones and other objects during the day tend to carry their stinger to one side, whereas burrowing scorpions hold their stinger up over their backs.

Scorpions are arthropods in the class Arachnida and order Scorpionida. Notable species of scorpions in the southwestern United States include the bark scorpion, which has venom that is dangerous to people; the Arizona hairy scorpion, the largest of the North American scorpions; and the stripedtail scorpion, one of the most common species. Other less common species of scorpions also occur in California and can be found from sea level to elevations above 7,000 feet. Like the Arizona hairy scorpion and the stripedtail scorpion, these species play a beneficial role in the environment and pose no real danger to humans.

The bark scorpion is found throughout Arizona, in the extreme southeastern portion of California near Arizona, and in southwestern New Mexico. In Mexico, the bark scorpion is found in Baja California Norte, Baja California Sur, and Sonora. Bark scorpions reach a length of 3 inches and have a very thin tail only 1/16 inch wide; the body is yellow without stripes or patterns. The bark scorpion is the only common climbing scorpion and does not normally burrow, but usually lives above ground under tree bark and in palm trees and crevices of rocky cliffs. Because it can ascend slump block walls or stucco, this species is the scorpion most likely to enter dwellings. The bark scorpion is attracted to moisture around homes and in the house. It also may be found in stacked lumber or bricks, firewood piles, cellars, and attics. It needs only a crack of 1/16 inch to enter a home.

The Arizona hairy scorpion, Hadrurus arizonensis, is a common desert species found in southern California and throughout Arizona. In southern California it has been reported in Imperial, Inyo, Kern, Los Angeles, Riverside, San Bernardino, and San Diego counties. At maturity it can be 5 to 7 inches in length. Like many other desert scorpions, the Arizona hairy scorpion is a burrower, but may also be found under rocks, logs, sleeping bags, and other surface objects. This scorpion can often be found around homes and in garages. It is a night feeder attracted to water, swimming pools, irrigated areas, or outside lights where food prey such as beetles, cockroaches, crickets, moths, and other insects are attracted as well. During the day it may be found in woodpiles, palm trees, and decorative bark, or under loose boards, woodpiles, rocks, or the bark of trees. Like some other scorpions, the Arizona hairy scorpion may enter homes in search of water. Common indoor places where it might be found are dark, cool areas in the bathroom or kitchen as well as crawl spaces, attics, and closets.

The stripedtail scorpion, Vaejovis spinigerus, is one of the most common scorpion species in southern California, Arizona, and the United States. It is a burrowing scorpion that is often found in sandy soil but can survive in a variety of habitats, from desert floor to rocky hillside. At maturity, the stripedtail scorpion is about 2-1/2 inches long and the body is striped on the upper side. This scorpion is venomous, but not considered dangerous. It may be found under common objects such as sleeping bags, shoes, and other similar items.

UC ANR Publication 74110