Giant House Spider, European House Spider
Eratigena atrica
Agelenidae (Funnel-Weavers), Order Araneae. Key family characteristics include three pairs of spinnerets with the posterior pair notably elongated, and a typical two-row eye arrangement.
Physical Description
Robust, elongated body with a broad cephalothorax and a long, tapering oval abdomen. Covered in fine, velvety setae giving a matte texture. Noticeable sexual dimorphism with females having larger abdomens and males possessing noticeably longer legs and swollen palps.
Size Estimate
Body length ranges from 10 to 18 mm for females and 9 to 15 mm for males, with a formidable leg span stretching up to 75 to 100 mm. This appears to be a mature adult specimen.
Coloration & Markings
Dull earthy tones featuring mottled browns, dirty yellows, and greys. The cephalothorax has indistinct lighter markings, and the abdomen displays a subtle, broken herringbone or chevron pattern running down the dorsal center.
Web Type
Builds a characteristic flat, dense sheet web that ends in a tubular retreat where the spider waits in ambush, typically constructed in corners of rooms, basements, or dark crevices.
Eye Arrangement
Eight small eyes arranged in two slightly curved, nearly parallel horizontal rows across the front of the clypeus, typical of funnel-weavers.
Leg Characteristics
Long, robust, tapering legs covered in visible spines and fine hair. They are held in a sprawling, flattened lateral posture which aids in rapid tactile detection of vibrations on the web sheet.
Venom & Safety Information
Venom Information
Contains mild neurotoxic and proteolytic venom used primarily to subdue invertebrate prey. Not specialized for defense against large vertebrates.
Medical Significance
Not medically significant. Bites are extremely rare, typically occurring only when the spider is pressed directly against bare skin. Symptoms are usually minor, comparable to a mild bee sting with localized redness and slight swelling.
Safety Recommendations
Keep living areas clear of clutter and seal foundational cracks. If a spider is found inside, safely capture it under a glass and release it outdoors, or allow it to remain undisturbed in a basement or outbuilding.
Habitat & Behavior
Habitat & Range
Native to Europe and introduced to parts of North America and Central Asia. Prefers dark, undisturbed human structures such as basements, cellars, garages, and sheds, as well as natural cavities like hollow logs and rock piles.
Behavior & Temperament
Timid and fast-running. Prefers to flee from disturbances rather than confront, but can display defensive posturing if cornered. Strictly non-aggressive toward humans unless trapped against the skin.
Diet & Prey
Generalist predator feeding primarily on crawling insects including roaches, silverfish, flies, beetles, and occasionally other spiders captured via the sheet web.
Seasonal Activity
Most visibly active during late summer and autumn, which coincides with the wandering mating season when mature males frequently venture out into open living spaces.
Description
The Giant House Spider is one of the largest and most dramatic dwelling spiders found in human structures. With its impressive leg span and swift, darting movements, it often startles homeowners, though it plays an invaluable role in natural pest control by managing household insect populations.
Key Features
Elongated spinnerets visible at the rear of the abdomen, sprawling long spiny legs, mottled brown chevron-patterned abdomen, and construction of a flat sheet web ending in a funnel retreat.
Similar Species
Hobo Spider (Eratigena agrestis) and Wolf Spiders (Lycosidae). Hobo spiders are very closely related and require microscopic examination of genitalia for definitive differentiation, while wolf spiders do not build webs and have distinctive large anterior median eyes.
Life Cycle
Females construct durable silken egg sacs in autumn, guarding them until they hatch. Spiderlings disperse via ballooning or direct crawling. Mating occurs primarily in late summer and autumn when mature males wander in search of females. Lifespan ranges from 2 to 3 years.
Ecological Importance
Serves as a top invertebrate predator in domestic and woodland microhabitats, effectively regulating populations of pest insects and serving as a food source for larger predators like birds and small mammals.
Conservation Status
Not evaluated by the IUCN, but populations are secure, abundant, and widely distributed globally due to human-facilitated dispersal.
Interesting Facts
Despite their intimidating size, Giant House Spiders once held the Guinness World Record for top running speed among spiders, capable of bursts reaching up to half a meter per second.
Photography Tips
Use a macro lens with a fast shutter speed to freeze movement. Photograph from a lateral or slightly overhead angle to capture the chevron abdominal pattern and the leg spination clearly without disturbing the spider.
Identified: 2026-09-10T18:57:26.118343