Giant House Spider
Eratigena atrica
Agelenidae (Funnel Web Weavers), Order Araneae
Physical Description
Robust body with a clearly separated cephalothorax and elongated oval abdomen, covered in fine setae giving a somewhat velvety texture. Females are typically larger and heavier-bodied, while males feature noticeably longer legs and enlarged palps.
Size Estimate
Body length ranges from 10 to 18 mm for females and slightly smaller for males, with an impressive leg span reaching up to 75 to 100 mm.
Coloration & Markings
Mottled brown, earthy tones, and yellowish markings. The carapace features darker longitudinal stripes, while the abdomen exhibits a complex, chevron-like or speckled pattern down the dorsal midline.
Web Type
Constructs a flat, dense sheet web that terminates in a tubular retreat where the spider hides, typically built in dark, undisturbed corners.
Eye Arrangement
Eight small eyes of roughly uniform size arranged in two slightly curved, horizontal rows across the front of the cephalothorax.
Leg Characteristics
Long, robust legs covered in visible spines and fine hairs, often showing faint dark banding. The legs spread out widely to enhance sensitivity to vibrations on the web.
Venom & Safety Information
Venom Information
Contains neurotoxic components designed for invertebrate prey. The venom is generally harmless to humans, rarely resulting in anything more than localized minor discomfort if a bite occurs.
Medical Significance
Not medically significant. Bites are extremely rare as these spiders are docile and would rather escape; any accidental bite typically causes only mild, temporary irritation similar to a mosquito sting.
Safety Recommendations
Keep areas clean and uncluttered to reduce hiding spots. If removal is necessary, use a glass and a piece of card to safely catch and release the spider outside.
Habitat & Behavior
Habitat & Range
Native to Europe and introduced to parts of North America and Central Asia. Favors human dwellings, basements, sheds, garages, and dark crevices, as well as natural rock piles and hollow logs outdoors.
Behavior & Temperament
Timid and fast-moving, these spiders prefer to flee when disturbed. They are primarily nocturnal hunters that rush out from their tubular retreat when prey triggers their sheet web.
Diet & Prey
Feeds primarily on various household and garden insects, including flies, roaches, beetles, and other spiders, subduing them with venom delivered via powerful chelicerae.
Seasonal Activity
Most commonly seen in late summer and autumn when mature males actively roam in search of females during the mating season.
Description
The Giant House Spider is one of the most recognizable and rapid household inhabitants. Known for its impressive size and swift movements, it constructs intricate funnel-shaped webs in quiet corners, quietly managing insect populations around homes and outbuildings.
Key Features
Large overall size, long spiny legs, mottled brown patterns with chevrons on the abdomen, and the characteristic flat sheet web ending in a funnel retreat.
Similar Species
Tegenaria domestica (Barn Funnel Weaver) and Eratigena agrestis (Hobo Spider), which can be distinguished primarily through microscopic examination of genital structures.
Life Cycle
Females produce disc-shaped egg sacs in late summer or autumn, depositing dozens of eggs that overwinter. Spiderlings emerge in spring, undergoing multiple molts to reach maturity with a typical lifespan of 2 to 3 years.
Ecological Importance
Acts as an effective natural predator of household pests and general insects, helping to control populations within residential structures and natural habitats alike.
Conservation Status
Not evaluated by the IUCN, but populations are widespread, stable, and highly abundant globally.
Interesting Facts
Despite their intimidating appearance and startling speed—capable of reaching speeds over a foot per second—they are entirely harmless to humans and actively help keep domestic spaces free of pests.
Photography Tips
Use a macro lens with adequate lighting to highlight the intricate patterns on the carapace and abdomen. Keep a safe distance to avoid startling the spider into sudden flight.
Identified: 2026-08-25T19:17:35.103160