Giant House Spider
Eratigena atrica (formerly Tegenaria duellica)
Agelenidae (Funnel-Weavers), Order Araneae. Key family characteristics include three pairs of spinnerets with the posterior pair notably elongated, and the construction of funnel-shaped sheet webs.
Physical Description
Robust and solidly built body with a distinct, elongated oval abdomen and a broad cephalothorax. The texture appears moderately glossy with fine hair coverage, and noticeable prominent forward-facing chelicerae (mouthparts).
Size Estimate
Body length is roughly 10-18 mm for females with a leg span reaching up to 45-75 mm, giving it a large, intimidating appearance. This specimen appears to be an adult male based on the enlarged pedipalps visible near the front.
Coloration & Markings
Uniformly dark brown to almost blackish coloration on the cephalothorax and legs, with a slightly lighter, mottled brown or greyish-brown abdomen showing faint chevron or spot patterns typical of the species.
Web Type
Builds a dense, non-sticky funnel web that features a retreat tube at one end and a broad, flat sheet of silk web extending outward to catch passing crawling insects.
Eye Arrangement
Eight small, dark eyes arranged in two closely grouped, slightly curved horizontal rows across the front of the cephalothorax, typical of funnel-weaver spiders.
Leg Characteristics
Long, robust, tapering legs covered in fine hairs and prominent spines. The legs are typically splayed out wide in a flattened resting posture characteristic of active ground dwellers.
Venom & Safety Information
Venom Information
Contains mild neurotoxic venom used primarily to immobilize insect prey. It is not specialized for vertebrate defense.
Medical Significance
Harmless to humans. Bites are extremely rare, generally only occurring if the spider is trapped directly against bare skin. Symptoms are typically minor, resembling a mild bee sting with local redness and temporary discomfort.
Safety Recommendations
Keep living spaces tidy and seal cracks around doors and windows. If relocation is necessary, place a glass over the spider and slide a piece of stiff paper underneath to safely carry it outdoors.
Habitat & Behavior
Habitat & Range
Native to Europe and introduced to parts of North America (particularly the Pacific Northwest). Prefers dark, undisturbed areas such as cellars, garages, woodpiles, sheds, and corners of indoor rooms.
Behavior & Temperament
Fast-running ground hunter that relies on its web for vibration detection rather than trapping prey. Generally non-aggressive, preferring to flee rapidly when disturbed, though mature males wander actively in search of mates.
Diet & Prey
Feeds on a wide variety of ground-dwelling insects, including roaches, beetles, flies, silverfish, and other spiders that cross its sheet web.
Seasonal Activity
Most commonly sighted in late summer and autumn (August to October) when mature males leave their webs to actively search for females.
Description
The Giant House Spider is one of the largest and most recognizable household spiders in its range. Known for its impressive leg span and surprising speed, it spends most of its time hidden in dark crevices or waiting inside its signature funnel web. Despite its intimidating size, it is a shy and beneficial pest controller.
Key Features
Large size, dark brown coloration, long spiny legs, prominent forward-facing chelicerae, and the presence of enlarged male pedipalps in adult males.
Similar Species
Hobo Spider (Eratigena agrestis) and Barn Funnel Weaver (Tegenaria domestica). Distinguishing often requires microscopic examination of genitalia, though giant house spiders are generally darker and larger.
Life Cycle
Females construct silken egg sacs in secluded areas in autumn, guarding them through the winter. Spiderlings hatch in spring, undergoing multiple molts to reach maturity over a 2 to 3-year lifespan.
Ecological Importance
Acts as an effective natural pest controller in homes and outbuildings by reducing populations of common household insects and other arthropods.
Conservation Status
Not evaluated by the IUCN, but populations are secure, widespread, and frequently expanding due to human habitation.
Interesting Facts
Giant house spiders were once recognized in the Guinness Book of World Records as one of the fastest running spiders, capable of reaching speeds up to 1.7 feet per second.
Photography Tips
Photograph from above or the side at a safe distance using natural light or a diffuser to avoid harsh shadows, ensuring the eye arrangement and leg spination are clearly visible.
Identified: 2026-08-16T09:59:21.715785