Giant House Spider
Eratigena duellica (formerly Tegenaria gigantea)
Agelenidae (Funnel Weavers), Order Araneae
Physical Description
A robust spider with a typical Agelenid shape: an oval cephalothorax and a bulbous, tapering abdomen. The body is covered in fine sensory hairs. This specimen appears to be a male, noted by the prominent, bulbous pedipalps at the front of the head which resemble small boxing gloves.
Size Estimate
Body length approximately 10-18mm; leg span likely 50-75mm. This appears to be an adult male searching for a mate.
Coloration & Markings
Dark brown to earthy tan base color. The cephalothorax features two broad, dark longitudinal stripes. The abdomen has a central pale 'herringbone' or chevron-like pattern flanked by darker spots.
Web Type
Funnel web; they build flat, horizontal sheets of non-sticky silk leading to a tubular retreat in a corner or crevice. They do not hunt on the web but wait for vibrations.
Eye Arrangement
Eight eyes of similar size arranged in two nearly straight rows of four. This provides excellent motion detection for catching prey on their silk sheets.
Leg Characteristics
Notably long and hairy legs, lacking the heavy banding seen in some relatives. They are capable of extremely high speeds, making them some of the fastest arachnids in northern climates.
Venom & Safety Information
Venom Information
Possess a mild neurotoxic venom used to subdue insects. It is not considered toxic to humans and is less potent than that of a common honeybee.
Medical Significance
Harmless and not medically significant. Bites are rare and usually occur only if the spider is squeezed. Symptoms are limited to minor redness and localized swelling similar to a mosquito bite.
Safety Recommendations
If found, they can be easily relocated using a cup and a piece of paper. Avoid using glue traps (as seen in the photo) which cause a slow death; use catch-and-release to benefit from their pest control.
Habitat & Behavior
Habitat & Range
Commonly found in the Pacific Northwest of North America and throughout Europe. They prefer dark, undisturbed microhabitats like basements, woodpiles, garages, and crawl spaces.
Behavior & Temperament
Very fast but shy. They are not aggressive and've a strong 'flight' response. Most encounters occur in autumn when males wander indoors looking for females.
Diet & Prey
Generalist predators eating flies, beetles, moths, and even other spiders (including the Hobo spider). They use their speed to dash out and grab prey that falls on their web.
Seasonal Activity
Most visible in late summer and autumn (August through October) when males emerge from hiding to find mates.
Description
The Giant House Spider is a common and often misunderstood roommate. Despite its imposing size and incredible speed, it is a beneficial predator that provides excellent natural pest control within homes.
Key Features
Large size, long hairy legs, twin stripes on the cephalothorax, and lack of distinct banding on the legs. Males have large, visible pedipalps.
Similar Species
Eratigena agrestis (Hobo Spider), which is smaller with shorter legs and less distinct markings; Tegenaria domestica (Barn Funnel Weaver), which is smaller with banded legs.
Life Cycle
Females can live several years; males typically die after the mating season. They produce several egg sacs containing 40-60 eggs each. Spiderlings often stay near the mother's web initially.
Ecological Importance
Crucial apex predators in the indoor/domestic ecosystem, regulating populations of silverfish, cockroaches, and nuisance flies.
Conservation Status
Not evaluated by IUCN, but populations are stable and widespread throughout their range.
Interesting Facts
At one point, these spiders held the Guinness World Record for the fastest spider speed (roughly 1.73 feet per second). They are also known to actively compete with and displace Hobo spiders.
Photography Tips
Focus on the 'palps' of the male and the dorsal pattern on the back. A side profile helps show the leg hairiness and body proportions clearly.
Identified: 2026-06-15T01:36:00.616034