Sun Spiders in Arizona

Sun spiders, also known as camel spiders and wind scorpions, are in fact neither spiders nor scorpions. Scientists refer to them as solpugids, and despite their fearsome appearance and startling speed, they are harmless. Several species of sun spiders inhabit Arizona and other U.S. Southwest states, where they may be encountered by gardeners and others who work outdoors.

Like spiders and scorpions, sun spiders are arachnids. They are somewhat similar in appearance to scorpions, though they lack claws and stinging tails. A sun spider has eight legs, with two additional blunt-ended limbs toward the front of its body; it uses those latter limbs to catch prey.

North American sun spiders are usually pale brown with flattened, segmented, sometimes darker abdomens that may appear swollen if the creatures recently ate prey. In Arizona, sun spiders are typically 5/8 to 1 3/4 inches long, but elsewhere in the world they grow as long as 6 inches. One of the sun spider's most noticeable features is its large, powerful mouth parts -- the largest of any land-dwelling invertebrate. It uses them to subdue its prey.

The warm climates and arid landscapes found in many parts of Arizona provide perfect sun spider habitats. Sun spiders feed on insects, spiders, scorpions and small vertebrates, and are also known to be cannibalistic. They are capable of running at speeds up to 10 mph and are well-suited to open desert areas, where they use their speed to chase down prey. Some small sun spiders are active during the day, but most of the larger individuals only come out at night, spending their days hiding under rocks and debris.

In spite of their formidable appearance, sun spiders are not a threat to humans. They do not possess stingers, and no species is known to be venomous. Sun spiders can deliver a strong bite that may break the skin, but they usually bite humans only when handled.

Contrary to their name, sun spiders prefer to avoid bright sunlight and sometimes run directly toward people to take shelter in their shadows or beneath their shoes. Coupled with their great speed, this characteristic can give sun spiders the appearance of attacking, when in reality they are only trying to avoid sunlight.

Sun spiders may be seen in gardens and lawns, especially when more suitable desertlike habitat is nearby. They are not harmful to plants and can benefit gardeners by controlling insect pests. If you see sun spiders outside, letting them be is the best practice.

They occasionally find their way into homes, especially during summer months, and may enter through cracks and other small openings. Repeated occurrences of sun spiders within a home may indicate an insect infestation because they most often find their way indoors in search of food. The University of Arizona Cooperative Extension recommends sealing potential entryways and trapping individual sun spiders and releasing them outside rather than resorting to chemical control.