Giant House Spider, European House Spider
Eratigena atrica (formerly Tegenaria duellica / Tegenaria atrica)
Agelenidae (Funnel-web weavers), Order Araneae. Key family characteristics include long spinnerets extending from the rear of the abdomen and the construction of sheet-like webs ending in a funnel-shaped retreat.
Physical Description
Robust body with a relatively flat cephalothorax and an elongated oval abdomen. The texture is covered in fine, velvety hairs rather than being spiny or smooth. Sexual dimorphism is present, with females possessing larger, heavier abdomens and males having noticeably longer legs relative to their body size and enlarged palps.
Size Estimate
Body length ranges from 10 to 18 mm for females and slightly smaller for males. The total leg span can reach up to 75 to 100 mm (3 to 4 inches), making it one of the largest spiders found indoors within its range. This appears to be a mature adult specimen.
Coloration & Markings
Earthy tones ranging from yellowish-brown, grayish-brown to dark brown. The cephalothorax features characteristic pale, yellowish longitudinal markings or spots (often described as a pattern resembling a skull or dagger markings). The abdomen displays a mottled pattern with a central lighter band bordered by darker spots or chevrons.
Web Type
Builds a characteristic non-sticky sheet web (funnel web) that is usually constructed in dark, undisturbed corners, behind furniture, or in basements. The web consists of a flat horizontal sheet with a tubular retreat at one end where the spider waits for prey.
Eye Arrangement
Eight small eyes arranged in two slightly curved, nearly parallel horizontal rows of four across the front of the cephalothorax. All eyes are relatively uniform in size and pearly-white in appearance.
Leg Characteristics
Long, robust, and tapering legs covered in visible hairs and noticeable spines. The legs lack distinct dark banding, maintaining a uniform brownish coloration. They are held spread out flat against the surface, radiating widely from the body.
Venom & Safety Information
Venom Information
Possesses mild neurotoxic venom used primarily to immobilize insect prey. The venom is not potent enough to pose a serious threat to healthy human adults.
Medical Significance
Harmless to humans. While large enough to potentially pierce human skin if tightly squeezed or provoked, bites are extremely rare and typically result only in mild, localized pain, redness, or swelling comparable to a mosquito or bee sting, with no systemic effects.
Safety Recommendations
No special precautions needed beyond standard home cleanliness. If relocation is desired, place a glass over the spider, slide a stiff piece of paper underneath, and release it outdoors. No medical treatment is necessary for encounters unless a secondary infection occurs from a scratch.
Habitat & Behavior
Habitat & Range
Native to Europe, Central Asia, and North Africa, but introduced to North America (particularly the Pacific Northwest) and other temperate regions globally. Prefers dark, humid environments such as basements, crawlspaces, sheds, and quiet indoor corners, as well as natural shelters like hollow trees and rock piles.
Behavior & Temperament
Timid and fast-moving. They are primarily nocturnal hunters that rush out of their funnel retreats to capture prey that wanders onto the sheet web. They are generally non-aggressive and will flee rapidly when disturbed rather than bite.
Diet & Prey
Generalist predators feeding on various indoor and outdoor arthropods, including crawling insects like beetles, cockroaches, flies, silverfish, and woodlice, as well as other smaller spiders.
Seasonal Activity
Active year-round indoors, but adult males become most visible in late summer and autumn as they actively wander in search of mates, frequently leading to human encounters.
Description
The Giant House Spider is an impressive yet harmless arachnid often encountered indoors as the weather cools in autumn. With its substantial leg span and velvety brown body, it frequently startles homeowners, though it plays a beneficial role by keeping household insect populations in check. True to its name, it is one of the fastest running spiders, capable of sudden bursts of speed.
Key Features
Large size, long hairy legs without prominent banding, pale yellowish mottled markings on the cephalothorax, and the construction of a flat sheet web ending in a tubular funnel retreat in dark corners.
Similar Species
Hobo Spider (Eratigena agrestis) and domestic house spider (Tegenaria domestica). Distinguishing them often requires microscopic examination of genitalia, though Giant House Spiders are typically much larger and darker with less distinct herringbone patterns than hobo spiders.
Life Cycle
Females produce disc-shaped egg sacs in late summer or autumn, containing up to several hundred eggs, which are hidden near the web retreat. Spiderlings hatch and disperse. The species can live for two to three years, molting multiple times before reaching maturity.
Ecological Importance
Serves as an effective natural pest controller in homes and outbuildings by preying on nuisance insects and other arthropods, helping to regulate indoor invertebrate populations.
Conservation Status
Not evaluated by the IUCN, but populations are stable, widespread, and thriving, frequently expanding alongside human habitation in introduced regions.
Interesting Facts
Despite their intimidating size, Giant House Spiders held the world record for spider running speed, reaching speeds up to 0.5 meters per second. They are poor climbers on vertical glass surfaces due to the lack of specialized claw tufts.
Photography Tips
Photograph from above or a slight side angle to capture the cephalothorax pattern and leg spread. Use natural lighting or a diffused flash to avoid harsh shadows, and maintain a calm distance to prevent startling the spider into running away.
Identified: 2026-08-05T08:45:06.550611