Wolf spiders and giant house spiders are two of the most common large spiders people encounter indoors, and they’re easy to confuse. Both are brown, hairy, and fast enough to make you jump. But they differ in key ways, from body shape and behavior to where you’ll find them and how they hunt. Neither poses a serious danger to humans.
Size and Appearance
Giant house spiders have a body length of roughly half an inch to one inch, but their leg span can reach up to four inches, which is what makes them look so alarming. They range from light brown to grayish-brown, and their markings vary wildly. Some have distinct stripes on their legs and body, while others look almost uniform in color. Their legs and body are somewhat hairy but not shiny. Because of all this natural variation, color and markings alone aren’t reliable for identifying them.
Wolf spiders are a large family with over 2,000 species, so their size range is broad: body length runs from about 3 millimeters (smaller than a grain of rice) to 30 millimeters (just over an inch). The species you’re likely to encounter indoors fall on the larger end. Females are often noticeably bigger than males. Their coloring leans into camouflage tones of brown, orange, black, and gray, frequently with stripes or blotches. The most distinctive visual feature is their eye arrangement: wolf spiders have two large, forward-facing eyes that reflect light brightly, sitting above a row of four smaller eyes. If you shine a flashlight at a wolf spider at night, those two big eyes glow back at you.
How to Tell Them Apart
The quickest way to distinguish the two is body proportion. Giant house spiders have relatively small bodies compared to their long, spindly legs, giving them a leggy, spread-out look. Wolf spiders are more compact and robust, with thick legs closer to their body. Think of it this way: a giant house spider looks built for speed across flat surfaces, while a wolf spider looks built for power and pouncing.
Behavior is another strong clue. If the spider sprints across your floor in a straight dash toward cover, it’s more likely a giant house spider. These spiders are famously fast runners. If the spider seems stockier and holds its ground or moves in short bursts rather than one long sprint, it’s more likely a wolf spider. And if the spider is carrying a round white or gray ball attached to its rear end, that’s almost certainly a female wolf spider with an egg sac, something giant house spiders don’t do.
Hunting and Web-Building
Neither of these spiders builds the classic circular webs you see in doorways. Giant house spiders construct messy, funnel-shaped sheet webs in corners, behind furniture, and in basements. They sit at the narrow end of the funnel and rush out to grab anything that stumbles onto the sheet. You’ll often notice the web before you notice the spider.
Wolf spiders don’t build webs for catching prey at all. They’re active hunters that chase down insects on foot, relying on speed, eyesight, and ambush tactics. Some species dig burrows in the ground and wait near the entrance. Others roam freely at night across lawns, leaf litter, and, occasionally, your kitchen floor. When you see a wolf spider indoors, it’s almost always a wanderer that came in through a gap near ground level, not a resident that set up a web in the corner weeks ago.
Where You’ll Find Them
Giant house spiders are especially common in the Pacific Northwest and parts of Europe. They favor dark, undisturbed indoor spaces: basements, garages, closets, attics, and the gaps behind large furniture. They can live comfortably indoors year-round, though males become more visible in late summer and early fall when they leave their webs to search for females. Those are the ones you see darting across the living room at night.
Wolf spiders are found across most of North America and prefer the outdoors. They live in leaf litter, under rocks, in garden beds, and in grassy areas. They enter homes near ground level, typically through cracks in foundations, gaps under doors, or spaces around utility lines. Basements, crawlspaces, and ground-floor rooms are the most common places to encounter them indoors. Most wolf spiders hunt at night, so daytime sightings are less common but not unusual.
Wolf Spider Maternal Behavior
One of the most distinctive things about wolf spiders is how they care for their young. A female wolf spider attaches her egg sac, a round silken globe, to the spinnerets at the tip of her abdomen and carries it everywhere. She holds her abdomen raised to keep the sac from dragging on the ground. If she gets separated from the egg sac, she’ll search aggressively until she finds it.
Once the spiderlings hatch, they climb up their mother’s legs and pile onto her back, gripping specialized hairs on her abdomen. She carries them for several weeks until they’re large enough to disperse on their own. If you see what looks like a spider covered in dozens of tiny spiders, that’s a wolf spider mother. It can be startling, but it’s harmless. Giant house spiders don’t exhibit this behavior.
Are Their Bites Dangerous?
Neither spider is medically significant. Wolf spider venom isn’t dangerous to humans. A bite may leave a red bump, some swelling, and minor pain, similar to a bee sting. Because of their size, wolf spiders can puncture the skin and leave visible fang marks, which can look worse than it is. These symptoms typically resolve on their own without medical attention.
Allergic reactions are possible but uncommon. Signs to watch for include a red line extending from the bite, rapidly spreading swelling or hives, difficulty breathing, or dizziness. These warrant medical attention. Otherwise, standard first aid is all you need: clean the area with mild soap and water, apply a cool compress for about 15 minutes each hour to reduce swelling, and use an over-the-counter pain reliever or antihistamine if the area is itchy or sore. Keep an eye on the bite for signs of infection over the following days.
Giant house spiders rarely bite at all. They’re fast enough to flee rather than fight, and most encounters end with the spider disappearing under furniture before you can react. On the rare occasion one does bite, the effect is comparable to a wolf spider bite: minor, temporary discomfort.
Managing Them Indoors
If you’d rather not share your home with either spider, the approach is the same for both. Seal gaps around doors, windows, and foundation cracks, especially at ground level. Reduce clutter in basements and garages where spiders find shelter. Sticky traps placed along baseboards and in corners are effective for monitoring and reducing indoor populations without chemicals.
Both spiders are beneficial. They eat insects, including flies, mosquitoes, ants, and other pests. A single wolf spider or giant house spider in a basement can significantly reduce the number of smaller nuisance bugs. If you can tolerate their presence, they’re working in your favor. If you can’t, a glass and a piece of cardboard over the top is the simplest way to catch and relocate them outdoors.