Giant House Spider
Eratigena duellica (formerly Tegenaria gigantea)
Agelenidae (Funnel-Weavers), Order Araneae. Key family characteristics include long, prominent spinnerets and the construction of flat, sheet-like webs ending in a funnel.
Physical Description
A large, robust spider with a hairy appearance. The cephalothorax is pear-shaped and the abdomen is oval with a distinctive mottled or chevron pattern. They possess long, hairy legs and noticeable spinnerets protruding from the rear of the abdomen.
Size Estimate
Body length 10-18mm for females, 12-15mm for males. Total leg span can reach 50-100mm (2-4 inches), making it one of the largest spiders in its range.
Coloration & Markings
Primarily earthy tones: tan, brown, and grey. The cephalothorax features two dark longitudinal stripes. The abdomen has a central light stripe with dark, lateral spots or chevron-like patterns.
Web Type
Constructs a flat, non-sticky sheet web with a silk-lined funnel retreat in one corner. Webs are typically built in dark, undisturbed corners of buildings or under rocks/logs.
Eye Arrangement
Six or eight eyes (usually eight) in two rows: the anterior row is nearly straight and the posterior row is slightly procured; the eyes are relatively uniform in size.
Leg Characteristics
Notably long and spindly but strong, covered in fine sensory hairs (trichobothria) and small spines. They do not have the heavy banding found in some other funnel-weavers but may show faint mottling.
Venom & Safety Information
Venom Information
Possesses a mild neurotoxic venom used to immobilize small insects. The venom is not considered toxic to humans or pets.
Medical Significance
Low medical significance. Bites are extremely rare and usually only occur if the spider is pinned against skin. Symptoms are typically limited to mild redness and slight swelling similar to a bee sting.
Safety Recommendations
If found indoors, they can be safely relocated by placing a jar over them and sliding a piece of paper underneath. Ensure crevices in foundations are sealed if you wish to prevent entry, but they are generally harmless and beneficial to keep around.
Habitat & Behavior
Habitat & Range
Common in the Pacific Northwest of North America and throughout Europe. They are synanthropic, frequently inhabiting houses, garages, basements, and sheds, as well as outdoor crevices.
Behavior & Temperament
Extremely fast runners but very shy and non-aggressive. They prefer to flee into their funnel or a dark crevice when disturbed. They are nocturnal hunters that wait in their funnel for vibrations on the sheet web.
Diet & Prey
Generalist predators feeding on various insects, including flies, beetles, moths, and even other spiders (including the Hobo spider). They use their speed to dash out and overpower prey.
Seasonal Activity
Sightings peak in late summer and early autumn (August-October) when mature males leave their webs to wander in search of females.
Description
The Giant House Spider is a common and often startling sight due to its impressive size and incredible speed. Often mistaken for more dangerous species, it is actually a beneficial roommate that helps manage indoor pest populations. Its long legs and mottled brown pattern are hallmarks of the Agelenidae family.
Key Features
Distinguished by its large size (up to 4 inches leg span), dark longitudinal stripes on the cephalothorax, and prominent, visible spinnerets. Its speed is a major diagnostic behavioral trait.
Similar Species
Often confused with the Hobo Spider (Eratigena agrestis), which is smaller and lacks the distinct dark spots on the sternum (visible from below), and Wolf Spiders (Lycosidae), which have a different eye arrangement and do not build webs.
Life Cycle
Females produce several globular, silk-wrapped egg sacs containing hundreds of eggs. Spiderlings emerge in spring. They can live 2-3 years, and males are often seen wandering in late summer/autumn looking for mates.
Ecological Importance
Acts as a major apex predator within the micro-ecosystem of human dwellings, providing excellent natural pest control against flies, gnats, and disease-carrying insects.
Conservation Status
Not listed by IUCN; populations are stable and widespread due to their successful adaptation to human-altered environments.
Interesting Facts
The Giant House Spider was once recorded as the fastest spider in the world in the Guinness Book of World Records, capable of reaching speeds of up to 1.73 feet per second.
Photography Tips
To document for identification, capture a clear top-down view (dorsal shot) of the cephalothorax patterns and the abdomen markings. Use a macro lens or high-resolution zoom to see the spinnerets.
Identified: 2026-06-15T01:35:31.766355