Giant House Spider vs. Wolf Spider: How Can You Tell Them Apart?
You can tell a giant house spider from a wolf spider by differences in leg proportions and stance, eye arrangement, body shape, and whether it constructs a web. Giant house spiders (Eratigena spp.) are long‑legged, gracile arachnids that build funnel‑shaped sheet webs in sheltered corners of buildings, whereas wolf spiders (family Lycosidae) are stockier, ground‑running hunters that do not spin capture webs and display a distinctive eye pattern with two relatively large middle eyes.
This distinction matters to Pacific Northwest homeowners because the region’s cool, wet climate, abundant forest edges, and many older homes with basements, crawlspaces, and outbuildings make indoor–outdoor spider encounters common. Giant house spiders frequently establish themselves inside structures during cooler months, while wolf spiders are primarily outdoor hunters that may wander into houses seasonally; correctly recognizing which type you’re seeing helps put their presence, typical behavior, and relative risk to people and pets into proper perspective.
Which giant house spider and wolf spider species are common in Seattle and the Pacific Northwest
In Seattle and the broader Pacific Northwest the “giant house spider” label typically applies to members of the Eratigena/Tegenaria group (formerly placed in Tegenaria). The two you’ll most often encounter indoors are Eratigena domestica (the common house spider) and representatives of the Eratigena atrica complex (sometimes reported as E. duellica/atrica in field guides); the non‑native hobo spider (Eratigena agrestis, formerly Tegenaria agrestis) is also established in parts of western Washington. These species were introduced from Europe and have adapted to basements, attics, eaves and window wells in temperate, humid Seattle neighborhoods.
Wolf spiders in the region are mostly ground‑running species from the genera Pardosa, Schizocosa and Trochosa. Pardosa spp. are the abundant, smaller “lawn” wolf spiders you’ll find in turf, garden beds and rocky shorelines around Puget Sound; Schizocosa and Trochosa include the bulkier, darker wolf spiders that frequent mulched beds and riparian edges. Local surveys and museum records for King and Snohomish counties show Pardosa dominating open, disturbed habitats, with Schizocosa/Trochosa more common in shaded, moist garden and forest margins.
Size and proportion differences help separate the groups in the PNW: adult Eratigena house spiders typically have a body length in the range of about 6–15 mm with a legspan commonly 25–45 mm (some large females in the atrica group approach 50–60 mm legspan). By contrast Pardosa wolf spiders normally have body lengths of roughly 4–12 mm and more compact leg proportions, while larger Trochosa/Schizocosa individuals reach body lengths of 12–20 mm with legspans commonly 30–60 mm. In short, Eratigena species tend to show longer, thinner legs relative to a smaller, elongated abdomen; many wolf spiders are stouter with proportionally shorter legs.
Seasonal and habitat patterns in Seattle reinforce identification: Eratigena spp. become conspicuous inside homes in late summer and autumn as mature males wander seeking mates (peak sightings September–November), and females will persist in sheltered corners year‑round. Wolf spiders are most active outdoors from spring through early fall, with peak juvenile dispersal and adult activity in May–August; they sometimes wander indoors on warm, humid nights but are primarily ground‑dwelling hunters in lawns, garden mulch and under stones. The Pacific Northwest’s mild, wet winters let both groups persist locally, but Eratigena’s synanthropic behavior makes them the dominant “big spider” seen inside Seattle residences.
How to tell giant house spiders and wolf spiders apart by size, body shape, and leg span
Adult giant house spiders in the Eratigena/Tegenaria group commonly encountered in Seattle have comparatively small bodies and very long, tapering legs: typical adult body (cephalothorax + abdomen) measures roughly 6–18 mm (0.25–0.7 in) while overall leg span commonly falls between 45–75 mm (1.8–3.0 in). Males are the lankiest and most conspicuous inside houses in late summer and early fall (August–October), when wandering males searching for mates often push leg span measurements to the upper end of that range. In contrast, the medium-sized wolf spiders found in suburban Seattle yards usually show body lengths of about 8–20 mm (0.3–0.8 in) for common Pardosa-type species, with typical leg spans of 20–50 mm (0.8–2.0 in); a few larger Lycosidae species can approach or slightly exceed 60 mm leg span, but those are less common in city gardens.
Shape and proportions provide a rapid visual cue: giant house spiders have elongated, somewhat flattened bodies and legs that are uniformly long and thin, giving a spidery, angular silhouette; the abdomen is often oblong with a series of chevron or longitudinal markings. Wolf spiders are noticeably more robust — the cephalothorax (front body) appears broader relative to the abdomen, and the abdomen is rounder or more compact. Wolf spiders’ legs are thicker, held at a more horizontal/stocky angle for sprinting, and the overall profile reads as stout rather than spidery-long.
Leg detail and spination help confirm identification under closer inspection: giant house spider legs are long, spindly, and sparsely bristled, with the first pair sometimes oriented forward when at rest; the joint segments are visibly long and tapered. Wolf spiders have stronger, more heavily bristled legs with short, stiff spines on the tibia and metatarsus that aid rapid running and grappling prey. Eye reflection is also diagnostic in many wolf spiders — the large posterior median eyes produce a visible tapetum reflection at night — whereas Eratigena species have smaller, less reflective eyes and rely on retreat webs and crevice refuges rather than night vision.
Seasonal and sexual dimorphism affects apparent size in Puget Sound-area observations: in Seattle’s mild, humid summers and warm, damp autumns, juvenile wolf spiders and house spiders can grow throughout the season and reach adult proportions by July–September. Male giant house spiders roaming indoors in August–October will commonly look dramatically larger than the sedentary females inside retreats because the males’ legs elongate proportionally during maturity. Conversely, gravid female wolf spiders in late spring and early summer may appear bulkier than males of the same species because they carry eggs or spiderlings, increasing body girth without substantially increasing leg span.
How to identify them by behavior and web use versus active hunting around Seattle homes
Giant house spiders in the Pacific Northwest are sit-and-wait predators that construct horizontal sheet-and-funnel webs 20–70 cm across with a narrow retreat 1–5 cm deep tucked into corners, eaves or basement crevices. They sit in the funnel and monitor the sheet for vibration; when an insect lands they sprint out along the silk for distances of 5–30 cm to seize prey. Adult males become noticeably more visible in Seattle from late summer into autumn (roughly August–November) when they abandon webs to wander indoors in search of mates, which is why homeowners often report increased sightings in those months.
Wolf spiders (family Lycosidae) common around Seattle are active ground hunters rather than web trappers: many local Pardosa and related species have body lengths from about 6–18 mm and legspans typically 15–45 mm, and they chase or ambush prey across soil, mulch and leaf litter. They do not build aerial capture webs; some dig silk‑lined burrows or make simple retreats under stones, but most rely on vision and vibration to locate prey. At night their large posterior eyes produce a characteristic eyeshine when light is shone at them, a useful identification cue that complements their habit of moving across open ground and foundation gaps rather than sitting in a silk sheet.
Local habitat and seasonality in Seattle influence where you’ll encounter each behavior: damp basements, crawlspaces and sheltered eaves with relative humidity often above 60% in fall and winter allow Eratigena funnel webs to persist for weeks, whereas wolf spiders are most obvious in drier, ground‑level habitats—mulch beds, lawns and rock borders—after spring and summer rains when invertebrate prey is abundant. Heavy autumn rains and dwindling outdoor prey can push wolf spiders indoors intermittently, but their presence indoors is typically transient and concentrated at floor level, not attached to walls or ceiling corners where giant house spider webs are anchored.
Behavior on direct encounter differs in predictable ways you can measure: a funnel‑weaver will almost always retreat toward a funnel or immediately run along silk lines (often within 1–5 cm of a corner), while a wolf spider will run across open surfaces, stop, and reorient to stalk or flee—wolf spiders can traverse several body lengths per second and are adapted for rapid ground pursuit. Female wolf spiders also show distinctive parental behavior not seen in web builders: they carry pale egg sacs attached to the spinnerets for around 1–3 weeks, and spiderlings ride on the mother’s back for roughly 7–14 days after hatching, a diagnostic field sign if you find brood-carrying adults in garden areas.
Are bites from giant house spiders or wolf spiders dangerous to people and pets in the Pacific Northwest
Both Eratigena spp. (giant house spiders) and Lycosidae (wolf spiders such as local Pardosa and Trochosa species) possess venom used to subdue insect prey, but their venoms are low in mammalian toxicity. In contrast to Pacific Northwest medically significant species like the western black widow (Latrodectus hesperus), whose envenomation can produce systemic neurotoxic effects within 1–3 hours, documented systemic reactions to giant house- or wolf‑spider bites are extremely uncommon in clinical literature for this region.
Typical local bite presentation is limited and short-lived: the puncture wounds are usually 1–2 mm in diameter, with immediate sharp pain comparable to a bee sting followed by localized erythema and swelling that commonly measures 1–5 cm across. Pain and swelling generally peak within the first 6–24 hours and resolve over 48–72 hours; persistent ulceration or necrosis is not a recognized feature of these genera in the Pacific Northwest. Because giant house spiders have relatively long chelicerae, a bite may feel more painful initially, but the pathological course is usually no worse than that from a wolf spider bite.
Allergic and infectious complications are the two main exceptions to the typical benign course. True IgE‑mediated anaphylaxis from a spider bite is rare but, when it occurs, signs (urticaria, wheeze, hypotension) typically begin within 5–30 minutes. Secondary bacterial infection after a bite can develop over 48–96 hours; look for increasing erythema beyond the initial 24 hours, warmth, purulent drainage, or spreading streaks suggestive of cellulitis. People with diabetes or immunosuppression in Seattle-area populations have a higher relative risk of such infectious complications.
Effects on companion animals are usually limited to transient local swelling and discomfort. Small dogs or puppies may show more pronounced signs—excessive licking, transient limping, mild vomiting or lethargy lasting 24–48 hours—because the venom dose per body weight can be proportionally larger. Seasonal and behavioral context changes the exposure risk: giant house spiders are more often encountered indoors in late summer and autumn in humid Seattle homes (leg spans up to 6–7 cm are common), while wolf spiders are ground‑active in spring and summer in gardens and are more likely to bite if handled or cornered outdoors.
What safe control and exclusion methods work best in Seattle homes and gardens for giant house spiders and wolf spiders
Start with structural exclusion: seal exterior gaps larger than about 1/8 inch (≈3 mm) with silicone caulk and use copper or stainless-steel mesh for voids bigger than 1/4 inch (≈6 mm). Fit door sweeps and threshold seals that reduce the under‑door gap to ≤6 mm and repair or replace window and attic screens with standard 18×16 insect mesh; inspect and reseal foundations, utility penetrations, and soffits each spring and again in late summer before the peak indoor migration of giant house spiders (typically August–October in the Seattle area).
Target habitat modification differently for ground‑active wolf spiders versus web‑building giant house spiders. For wolf spiders, remove leaf litter, keep mulch layers to 2–3 inches and set mulch back 6–12 inches from foundations, elevate firewood at least 12 inches off the ground and store it 10–20 feet from the house, and trim shrubs so there is a 12‑inch clear zone between foliage and siding. For giant house spiders, reduce sheltered outdoor harborage within 6–8 feet of doors and windows (stacked boxes, open eaves, dense ivy) because those structures serve as staging areas for females that enter homes to mate in late summer.
Interior housekeeping and mechanical removal are high‑value, low‑toxicity tactics. Vacuum webs, egg sacs and corners weekly during summer and fall migration; giant house spider egg sacs in webs are roughly pea‑sized (about 6–12 mm) and removing them before hatching cuts juvenile influx. Place glue boards along baseboards, behind furniture and near entry points (check weekly) — glue traps tend to be more effective for the vertically traveling Eratigena/house spider group than for larger, ground‑running wolf spiders, which are more often caught by traps placed at floor thresholds, garages and basements.
When chemical or dust options are necessary, choose low‑toxicity, targeted products and plan for Seattle’s damp climate. A light dusting of food‑grade diatomaceous earth or silica desiccant in crawlspaces, under porches and inside wall voids can be left in place and rechecked after heavy rain or every 2–3 months; expect gradual mortality over days rather than immediate results. Short‑range pyrethrin spot treatments in cracks and voids will give quick knockdown but degrade faster in high humidity, so rely on exclusion and habitat removal as the primary long‑term strategy and reserve residuals for localized, persistent harborage.
How can I tell a giant house spider from a wolf spider?
Giant house spiders (Eratigena spp.) have long, thin legs, an elongated flattened body, and sit in horizontal sheet‑and‑funnel webs in corners, while wolf spiders (Lycosidae) are stockier with proportionally shorter, thicker legs, do not build capture webs, and are active ground hunters. Wolf spiders also show a distinctive eye arrangement with two relatively large middle eyes that often produce eyeshine at night.
Are bites from giant house spiders or wolf spiders dangerous to people or pets in Seattle?
Bites from both groups are uncommon and their venom is of low mammalian toxicity; typical local reactions are brief sharp pain, small puncture marks, and localized swelling that usually resolves in 48–72 hours. Seek medical care promptly for signs of anaphylaxis (wheezing, hives, hypotension) or for increasing redness, pus, or spreading warmth that could indicate secondary infection, and note that medically significant envenomation in the region is more associated with western black widows, not these spiders.
Why do I see more giant house spiders in my Seattle house in the fall?
Adult male Eratigena house spiders commonly wander indoors in late summer and autumn (peak sightings August–November) while searching for mates, so you’ll notice more large, long‑legged spiders in basements, eaves and corners during that period. Females and their funnel webs can persist year‑round in sheltered, humid parts of homes, making indoor encounters more frequent in the Pacific Northwest’s cool, wet climate.
What safe, non‑chemical steps will reduce wolf spiders and giant house spiders around my Seattle home?
Seal exterior gaps ≥3 mm with silicone caulk, fit door sweeps and screens (reduce under‑door gaps to ≤6 mm), remove leaf litter and keep mulch 2–3 inches deep and set back 6–12 inches from foundations, and reduce stacked clutter and dense ivy near entry points. Inside, vacuum webs and egg sacs regularly, use glue boards along baseboards and entryways, and consider targeted diatomaceous earth in crawlspaces or voids as a low‑toxicity option before resorting to residual pesticides.