Only two groups of spiders found in American homes are a real medical concern: widow spiders and recluse spiders. A black widow is shiny black with a red hourglass shape on the underside of its belly, and it likes cluttered, quiet spots like garages and woodpiles. Recluse spiders are tan to brown with a darker violin-shaped mark on their back, and in the states we serve, they’re mainly an Arizona concern. Nearly every other spider you’ll find indoors, from the big hairy one on the basement floor to the leggy one in the bathroom corner, looks worse than it is.
October is when many homeowners encounter their first big spider of the year. You flip on the garage light, and something the size of a quarter darts across the floor and under the shelving. Your first question is whether it can hurt you. Your second is whether there are more.
Fall brings spiders into view for a couple of reasons. Many males spend late summer and autumn wandering in search of a mate, and that search takes them under doors and through gaps around windows. Cooler nights also push spiders toward sheltered spots outside your home.
Spider identification for a homeowner doesn’t take a microscope. A few simple features will sort almost any spider into “leave it alone and call us” or “relocate it with a cup and move on.”
Black Widows Are the Ones to Know
Some type of widow spider lives in every state we serve. The western black widow lives across our western states, from Arizona up to Colorado. The northern black widow lives in Michigan and the Northeast. They look and behave nearly the same.
Here’s what to look for:
- A glossy black body about the size of a pea, round like a small berry
- On the underside, a red or orange hourglass (the northern black widow’s hourglass is sometimes split into two pieces)
- Webs that look messy and tangled instead of round, usually low to the ground
- If you see one hanging upside down in that web at night, you’re likely looking at an adult female
Female black widows have the stronger bite. Their venom affects the nerves, and a bite can cause muscle cramps and stomach pain that spread well past the bite itself. Deaths are extremely rare, but a bite is still worth a call to your doctor.
What surprises homeowners is how shy these spiders are. Black widows almost never come looking for people. Most bites happen when someone reaches into a spot without looking: a pair of gardening gloves left in the shed, the underside of a patio chair, the back of a stack of firewood.
Recluse Spiders and Where They Live
The brown recluse gets more attention than almost any other spider, but its home range sits mostly in the south-central and lower Midwest states. Everywhere else we work, a true brown recluse is rare and usually arrives as a hitchhiker in moving boxes or furniture from another state.
Arizona is a different story. The desert recluse and the Arizona recluse are both native to the state, and around Phoenix they hide in garage clutter, closet boxes, and the gap behind a dresser.
To tell a recluse apart from the many brown spiders that look similar, check for:
- A dark violin shape on the front part of the body, with the neck of the violin pointing toward the rear
- Legs that are one even color, with no stripes, bands, or spots
- Six eyes arranged in three pairs instead of the usual eight (you’ll need a magnifying glass for this)
- A habit of hiding during the day and roaming at night
In some cases, a recluse bite can cause a slow-healing sore. Most bites heal without trouble. Many skin wounds blamed on recluse spiders are actually bacterial infections, so see a doctor if a wound grows or darkens over a few days.
Scary-Looking Spiders That Are Mostly Harmless
Most spiders that make people jump onto the couch are harmless to humans. They also eat other bugs.
Wolf spiders are the big ones. They’re hairy and quick, usually brown or gray, and they run along floors instead of sitting in a web. Hold a flashlight up near your eyes and sweep it across your yard at night, and their eyes glint back at you. A wolf spider bite can sting like a bee, but that’s about it. Read more in our post on whether wolf spiders are venomous.
A few others you’ll run into:
- Jumping spiders: compact and fuzzy, with two large front eyes that seem to watch you. Our post on whether jumping spiders are poisonous explains why they’re no threat.
- Cellar spiders: pale and thin, with legs many times longer than their bodies, living in loose webs in basement corners. The old story that they’re secretly the most venomous spider around is a myth.
- Common house spiders: small and brownish, building tangled webs in upper corners and behind furniture. Our house spider guide covers what keeps them coming back.
- Orb weavers: if a big round web appears across your porch light in early fall, one of these garden spiders built it overnight.
A Few Spiders in the Middle
The yellow sac spider is pale yellow or beige and crawls along walls and ceilings at night, especially in fall. It hides in a small silk pouch in a corner or behind a picture frame. Its bite can cause redness and mild pain for a day or two.
The hobo spider lives in parts of Utah and Colorado. For years, it had a reputation for causing serious wounds, but newer research hasn’t backed that up. It looks a lot like several other brown, fast-moving spiders and isn’t considered a medical concern today.
What to Do If a Spider Bites You
If you can do it without getting bitten again, trap the spider in a jar or take a clear photo. Knowing the spider makes it easier for your doctor to help.
For most bites, wash the area with soap and water and apply a cold pack to reduce swelling. Call your doctor or the Poison Help line at 1-800-222-1222 if pain spreads, muscles start to cramp, or the bite turns into a sore that keeps growing.
If you have trouble breathing or feel severe pain, get emergency care right away. Our spider bite guide explains what different bites look like.
When One Spider Turns Into Many
One wolf spider in the garage in October isn’t a reason to worry. A black widow under the grill cover is different. So is a basement full of webs. Spiders stick around where there’s food, so a steady spider problem usually means other bugs are nearby.
Our spider pest control service starts with an inspection of where spiders like to hide, then treats around your home with botanically derived products. Our pest-free guarantee™ provides year-round protection against more than 30 common household pests, including widow spiders, brown recluses, and house spiders.
We treat on a regular schedule, and if spiders come back between scheduled services, we’ll return as many times as you need. We’ve been helping families with spiders since 2015.
Call us at (888) 291-5333 or reach out through our contact page, and we’ll help you figure out what’s living in your garage.
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