Wolf spiders and black house spiders are two of the most common spiders people encounter in and around their homes, but they differ significantly in appearance, behavior, and habitat. If you’ve spotted a spider and aren’t sure which one you’re dealing with, a few key features make them easy to tell apart.
How to Tell Them Apart
Wolf spiders are robust, ground-dwelling hunters with long, hairy legs. They’re usually brown to tan, sometimes with black markings, and range from about half an inch to over an inch in body length. Their most distinctive feature is their eye arrangement: four small eyes in a straight row at the front, a middle pair of larger eyes, and a rear pair of widely spaced eyes on top of the head. This gives them excellent vision for tracking prey. If you shine a flashlight at a wolf spider at night, its eyes reflect bright green.
Black house spiders (Badumna insignis) are smaller and darker, with a velvety black or dark brown body. They’re stockier and more compact than wolf spiders, and their legs are less obviously long or hairy. Unlike wolf spiders, they build messy, lace-like webs with a funnel-shaped retreat, typically in window frames, doorways, corners, and around outdoor lighting. If you see a tangled web with a distinct tunnel entrance, you’re almost certainly looking at a black house spider’s work.
The Quickest Way to Identify Each
- Web or no web: Wolf spiders don’t build webs to catch prey. They actively hunt on the ground, often sprinting after insects. Black house spiders are committed web builders.
- Eye shine: A flashlight at night will reflect green off a wolf spider’s large posterior eyes. Black house spiders lack this reflective quality.
- Color: Wolf spiders tend toward brown and tan with subtle markings. Black house spiders are distinctly darker, often charcoal to black.
- Movement: Wolf spiders are fast runners you’ll see darting across floors, patios, or leaf litter. Black house spiders stay close to their webs and rarely wander.
Where Each Spider Lives
Wolf spiders are found on every continent except Antarctica, with roughly 2,300 known species worldwide. They thrive in an enormous range of habitats: forests, deserts, mountains, marshes, grasslands, and suburban yards. Some species hunt along the edges of ponds and can even dive underwater to catch prey. Indoors, they don’t set up permanent residence so much as wander in accidentally, especially during fall when temperatures drop. You’ll typically find them at ground level, in garages, basements, or running across a floor at night.
Black house spiders are native to Australia but have established populations in other parts of the world, including New Zealand and Japan. They strongly prefer human structures, building their webs around window frames, eaves, gutters, fences, and bark on trees. They’re attracted to outdoor lighting because it draws the insects they feed on. Once a black house spider establishes a web, it tends to stay and keep repairing and expanding it rather than relocating, which is why their webs can become thick and layered over time.
Are Their Bites Dangerous?
Neither spider poses a serious medical threat, though both can bite if handled or accidentally pressed against skin.
Wolf spider bites look similar to other bug bites: a red bump with some swelling and possible fang marks. The venom isn’t dangerous to humans. Because of the spider’s size, the bite can be painful in the moment, but symptoms typically resolve on their own without medical treatment. Pain and itching are the most common complaints.
Black house spider bites are infrequent because the spiders are timid and tend to retreat into their funnel-shaped web when disturbed. When bites do occur, they can be quite painful with local swelling. Occasional symptoms include nausea, vomiting, sweating, and dizziness. In rare cases involving multiple bites, skin lesions have been reported. For a single bite, symptoms generally resolve without intervention.
What to Do if You’re Bitten
For bites from either spider, the same basic first aid applies. Wash the area with warm, soapy water, then apply an antibiotic cream to prevent infection. A cool washcloth or ice pack helps reduce swelling, and an over-the-counter antihistamine can ease itching and puffiness. If a spider lands on you, brush it off rather than crushing it against your skin, which increases the chance of a bite.
Allergic reactions are rare but possible with any spider bite. Signs include a red line extending outward from the bite, rapidly growing hives, facial swelling (especially around the mouth), difficulty breathing, or dizziness. These warrant emergency care.
Keeping Both Spiders Out of Your Home
Regular, thorough cleaning is the single most effective way to discourage spiders indoors. A broom or vacuum removes spiders, webs, and egg sacs efficiently. Both species are drawn to quiet, undisturbed spaces like closets, garages, basements, and attics, so reducing clutter in those areas makes your home less inviting.
Outside, move firewood, stacked materials, and debris away from your home’s foundation. Trim shrubs, vines, and tree branches that touch the house, since these give spiders a direct bridge to the structure. Tight-fitting window screens and door sweeps block entry points.
Lighting matters more than most people realize. Black house spiders in particular set up webs near outdoor lights because those lights attract insects. Switching to yellow or sodium vapor bulbs at exterior entrances draws fewer night-flying insects and, in turn, fewer spiders. For wolf spiders, which hunt on the ground rather than building webs near lights, sealing gaps at door thresholds, garage entrances, foundation vents, and the bottom edge of siding is more effective. Barrier insecticide sprays applied around the building perimeter can also reduce spider entry, though they typically need reapplication every month or two during warmer seasons.