Giant House Spider
Eratigena duellica
Agelenidae (Funnel Weavers), Order Araneae. Key family traits include long dorsal spinnerets and the construction of non-sticky funnel-shaped webs.
Physical Description
A large, robust spider with a typical agelenid shape. It features a pear-shaped cephalothorax and an elongated oval abdomen. The body is covered in fine, short hairs (setae) giving it a velvety appearance. Females are larger-bodied, while males have smaller abdomens and significantly longer, spindly legs.
Size Estimate
Body length 10-18mm for females; leg span can reach 45-75mm. This specimen appears to be an adult, likely a male given the leg-to-body proportion.
Coloration & Markings
Generally earthy tones of brown, beige, and charcoal. The cephalothorax features two broad, dark longitudinal stripes. The abdomen displays a central pale 'herringbone' or chevron pattern bordered by darker spots. The legs are typically uniform brown without distinct rings in adults, unlike the related Barn Funnel Weaver.
Web Type
A flat, sheet-like funnel web made of non-sticky silk. The web leads into a narrow silk tube or 'funnel' where the spider retreats. Typically built in corners, window wells, or wall-floor junctions.
Eye Arrangement
Eight eyes of similar size arranged in two slightly curved rows of four. This arrangement is characteristic of Agelenidae, providing a wide field of view to detect vibrations and movement near the web entrance.
Leg Characteristics
Notably long and hairy. They lack the heavy spination seen in wolf spiders. The legs are quite agile, designed for rapid sprints across and away from the web. In males, the legs appear disproportionately long.
Venom & Safety Information
Venom Information
Neurotoxic venom specialized for insect nervous systems. It is not considered toxic to humans. The venom is mild and intended to quickly immobilize small invertebrate prey.
Medical Significance
Low medical significance. The spider is reluctant to bite and will usually run away. If a bite occurs, it is generally less painful than a bee sting, resulting in localized redness or slight swelling that subsides quickly.
Safety Recommendations
If relocation is desired, use the 'cup and paper' method. They are harmless; ensuring cracks in windows and doors are sealed can reduce their entry into living spaces. No medical treatment is usually necessary for the rare bite beyond basic cleaning.
Habitat & Behavior
Habitat & Range
Commonly found throughout Europe and the Pacific Northwestern United States and Canada (where it is an introduced species). It prefers dark, undisturbed areas like basements, attics, sheds, and window screens.
Behavior & Temperament
Extremely fast runners, once holding a Guinness World Record for spider speed. They are generally shy and non-aggressive, preferring to retreat into their funnel at the slightest vibration. They are nocturnal hunters.
Diet & Prey
Generalist predators feeding on various insects, including flies, moths, beetles, and even other spiders. They detect prey through vibrations on the silk sheet, dash out to bite, and drag the prey into the funnel.
Seasonal Activity
Active year-round indoors, but most visible in late summer and autumn (August-October) when mature males wander in search of females.
Description
The Giant House Spider is a common sight in temperate homes, often causing alarm due to its impressive size and speed. Despite its fearsome appearance, it is a beneficial 'roommate' that provides excellent natural pest control. It is a master of the sprint, utilizing its long legs to overtake prey on flat surfaces.
Key Features
Large leg span, diagnostic herringbone pattern on the abdomen, two dark stripes on the cephalothorax, and the presence of a funnel-shaped retreat.
Similar Species
Often confused with Tegenaria domestica (Barn Funnel Weaver), which is smaller and has banded legs, or Eratigena agrestis (Hobo Spider), which has less distinct abdominal markings and shorter legs relative to its body.
Life Cycle
Females produce several white, lens-shaped egg sacs containing up to 60 eggs, often incorporated into the web. Juveniles molt several times before reaching maturity. Adults can live 2-3 years, which is long for a temperate spider.
Ecological Importance
Crucial for indoor and peri-domestic pest management. They consume large quantities of houseflies, earwigs, and other spiders, maintaining a balance in the micro-ecosystem of human dwellings.
Conservation Status
Not evaluated by the IUCN, but populations are stable and widespread. They thrive in human-modified environments.
Interesting Facts
Until 2013, they were classified under the genus Tegenaria. They were once clocked at speeds of 1.73 ft/s (0.53 m/s). During autumn, males are often found in sinks and bathtubs as they wander looking for mates and fall in, unable to climb the smooth porcelain.
Photography Tips
Photograph from a top-down (dorsal) angle to show the abdominal pattern. Use a flash to illuminate the dark markings, as they are often found in low-light corners.
Identified: 2026-07-19T13:38:41.263782