About Spiders
Most spiders found in Idaho homes are harmless and help control other insects. A small number of species warrant more caution. This page covers the species Idaho homeowners are most likely to encounter and how to tell them apart.
What Do Spiders Look Like?
Spiders are arachnids, which means they have eight legs and two main body segments: the cephalothorax (front) and the abdomen (back). They vary widely in size, shape, and color depending on the species, but there are some common features to help you identify them.
Key features of spiders include:
- Eight legs: All spiders have eight jointed legs, unlike insects, which have six.
- Two body segments: A cephalothorax and an abdomen.
- Varied sizes: Ranging from tiny pinheads to several inches across, depending on the species.
- Color and markings: Colors range from brown, black, or gray to more vibrant patterns in some species.
- Silk-producing spinnerets: Located at the rear of the abdomen, used to spin webs or wrap prey.
Common Idaho Spiders
Hobo Spider
One of the most frequently encountered spiders in Idaho homes. Hobo spiders are light to medium brown with subtle chevron-shaped markings along the abdomen. Adults reach about half an inch in body length. They build funnel-shaped webs at ground level in basements, crawl spaces, garages, and along baseboards. Hobo spiders do not climb smooth surfaces well, which is why they are almost always found low to the ground. They are not considered a significant medical threat, though their bites can cause localized irritation in sensitive individuals.
Wolf Spider
Wolf spiders are large, fast-moving, and heavily built with a hairy appearance. Adults range from about half an inch to over an inch in body length, with leg spans reaching up to four inches. They are brown to gray with darker stripes or mottled markings along the back. Wolf spiders do not build webs. They hunt actively, which is why they are often spotted running across floors, patios, and garage spaces. They are frequently mistaken for more dangerous species due to their size. Their bite is not medically significant for most people.
Cellar Spider
Cellar spiders are easily identified by their extremely long, thin legs and small pale gray or tan body. They hang upside down in loose, irregular webs in basements, crawl spaces, garages, and closets. When their web is disturbed, they vibrate rapidly, which has earned them the nickname "vibrating spider." Cellar spiders are completely harmless to humans. They are also known to capture and feed on other spiders, including species larger than themselves.
Common House Spider
The most frequently seen web-building spider inside Idaho homes. Adults are small, roughly a quarter inch long, yellowish-brown with a rounded abdomen and mottled markings. They build messy, tangled cobwebs in ceiling corners, window frames, and behind furniture. Common house spiders are not aggressive and pose no threat to humans. Their webs are more of a nuisance than a concern.
Yellow Sac Spider
Yellow sac spiders are small, pale yellow to light green, and typically under half an inch long. Unlike most house spiders, they do not build capture webs. Instead, they construct small silk tubes or sacs in corners, along wall-ceiling joints, and behind furniture where they rest during the day. They are active hunters at night. Yellow sac spiders are the most common source of indoor spider bites in Idaho because of their tendency to wander across surfaces where they make contact with people. Bites typically cause mild to moderate localized pain and redness, but are not medically serious for most people.
Jumping Spider
Jumping spiders are small, compact, and densely covered in hair. They range from about a quarter to three-quarters of an inch and come in a variety of colors, though many Idaho species are black, gray, or brown with lighter markings. They have large, forward-facing eyes that give them exceptional vision. Jumping spiders do not build webs to catch prey. They stalk and leap onto insects with precision. They are commonly found on walls, fences, window frames, and in gardens. Jumping spiders are not harmful to humans and are generally considered beneficial.
What Do Spiders Eat?
Spiders are carnivorous and primarily feed on insects and other small arthropods. Their diet can include flies, mosquitoes, ants, beetles, and even other spiders. Web-building spiders often catch prey that gets trapped in their sticky silk, while hunting spiders actively stalk or ambush their meals. By feeding on insects, spiders play an important role in keeping pest populations under control in gardens, yards, and even inside homes.
Where Are Spiders Commonly Found?
Spiders can be found almost anywhere, but they prefer locations that offer shelter and a steady supply of insects. Many are drawn to corners, basements, attics, and crawl spaces inside homes, while others thrive outdoors in gardens, woodpiles, shrubs, and under rocks or debris. Web-building species often stay in areas where flying insects are abundant, whereas hunting spiders roam open spaces in search of prey.
What Are The Risks of Having a Spider Infestation?
A spider infestation can be unsettling and, in some cases, problematic. While most spiders are harmless, large numbers can create unsightly webs around the home, making spaces feel cluttered and unkempt. Some species have venomous bites that can pose a health risk, especially to children, pets, or those with allergies. Additionally, an abundance of spiders may indicate a high insect population, meaning other pests could also be present in your home or yard.
If you're in the Boise area, you can count on Affinity Pest Control for professional spider removal services that are fast, effective, and tailored to your home’s needs.