Giant House Spider, European House Spider
Eratigena atrica (formerly Tegenaria duellica / Tegenaria atrica)
Family Agelenidae (Funnel-web weavers), Order Araneae. Key family characteristics include three pairs of spinnerets with the posterior pair being noticeably elongated, and building characteristic sheet-like webs that lead to a tubular retreat.
Physical Description
The giant house spider has a robust, elongate body with a distinctively patterned cephalothorax and an oval-shaped abdomen. The body texture appears slightly velvety or sparsely bristled with fine hairs rather than heavily spined. Visible features include prominent pedipalps and robust legs typical of fast-running funnel weavers.
Size Estimate
Body length typically ranges from 11 to 18 mm for females (sometimes up to 18.5 mm) and 10 to 15 mm for males. The total leg span can reach up to 45 to 75 mm, making it one of the larger house-dwelling spiders found in its range.
Coloration & Markings
The base coloration ranges from dull brown to yellowish-brown. The cephalothorax features distinct darker brown longitudinal stripes or markings. The abdomen exhibits a recognizable, complex pattern consisting of a lighter central yellowish band flanked by symmetrical dark spots and chevron-like markings.
Web Type
Builds a flat, non-sticky sheet web (funnel web) that extends out from a retreat tunnel or crevice where the spider hides. The sheet functions to intercept walking prey rather than airborne insects.
Eye Arrangement
Eight eyes of roughly equal size arranged in two slightly curved, closely spaced horizontal rows across the front of the carapace, typical of the Agelenidae family.
Leg Characteristics
Long, robust, tapering legs covered in fine hairs and prominent spines. The legs are generally uniform brown without distinct banding, built for rapid acceleration and running rather than climbing smooth vertical glass.
Venom & Safety Information
Venom Information
Produces a mild neurotoxic venom used primarily to immobilize insect prey. Their chelicerae can occasionally pierce human skin if firmly pressed, but the venom poses no significant medical threat to humans.
Medical Significance
Not medically significant. Bites are extremely rare, usually occurring only when the spider is trapped against human skin. Symptoms, if any, are typically limited to minor, localized pain, redness, or swelling similar to a mild bee sting.
Safety Recommendations
No special control measures are required as they are harmless. If relocation is desired, place a cup over the spider, slide a piece of paper underneath, and release it outdoors in a sheltered spot.
Habitat & Behavior
Habitat & Range
Native to Europe and introduced to parts of North America (particularly the Pacific Northwest). Prefers dark, undisturbed areas, commonly found indoors in basements, attics, behind furniture, in crawlspaces, and outdoors in woodpiles, sheds, and under rocks.
Behavior & Temperament
A nocturnal, fast-running hunter that spends most of its time waiting in its funnel retreat. They are generally non-aggressive and will flee rapidly from disturbance rather than bite, though mature males wander actively in autumn searching for mates.
Diet & Prey
Feeds primarily on crawling household insects such as cockroaches, beetles, woodlice, flies, and other spiders. They subdue prey using speed and venom after it walks onto the sheet web.
Seasonal Activity
Most commonly noticed in late summer and autumn when mature males leave their webs to actively search for females, increasing encounters with humans indoors.
Description
The giant house spider is a familiar and impressive arachnid guest in many homes. Known for its remarkable speed and impressive leg span, this funnel-weaver spends its life constructing flat sheet webs in quiet corners, basements, and wall voids. While their large size and sudden movements can startle homeowners, they are beneficial predators that help control household pest populations.
Key Features
Distinguished by large size, long spiny legs, mottled yellowish-brown chevron pattern on the abdomen, dark longitudinal stripes on the cephalothorax, and construction of a flat sheet web ending in a funnel retreat.
Similar Species
Can be confused with the Hobba Spider (Eratigena agrestis) or Wolf Spiders (Lycosidae). E. agrestis is similar in appearance but requires microscopic examination of genitalia for definitive separation; Wolf spiders typically hunt actively without building sheet webs and have distinctly larger posterior median eyes.
Life Cycle
Females construct silk egg sacs in hidden areas during autumn, containing up to dozens of eggs. Spiderlings hatch in spring, molt multiple times as they grow, and can live for 2 to 3 years. Mature males often die after wandering in search of females during late summer and autumn.
Ecological Importance
Acts as an effective natural pest controller in domestic and semi-natural environments by regulating populations of crawling insects and other arthropods.
Conservation Status
Not evaluated by the IUCN, but populations are stable, widespread, and thriving in association with human habitations.
Interesting Facts
Despite their intimidating size, giant house spiders are exceptionally fast runners, having once held a spot in the Guinness Book of World Records for top spider speed (reaching speeds up to 0.5 meters per second). They spend almost their entire lives off the ground inside buildings.
Photography Tips
Use natural or diffused lighting to capture the fine details of the abdominal chevron patterns and cephalothorax stripes. Maintain a calm distance to avoid startling the spider into fleeing into a dark crevice.
User Notes
Found in wall in house
Identified: 2026-08-28T20:16:06.333301