Giant House Spider
Eratigena duellica
Agelenidae (Funnel-Web Spiders), Order Araneae
Physical Description
A large, robust spider with a cephalothorax featuring two dark longitudinal stripes and a bulbous, mottled abdomen. Their bodies are covered in fine, dense hairs, giving them a velvety texture. They have very long legs relative to their body size, especially in males.
Size Estimate
Body length 10-18mm; leg span up to 75-100mm (3-4 inches). This specimen appears to be an adult.
Coloration & Markings
Predominantly brown, tan, and grey. The cephalothorax has dark stripes on a lighter background, while the abdomen features a series of chevrons or spotted patterns. Legs are usually solid brown without distinct banding seen in some relatives.
Web Type
Large, flat sheet of silk leading into a non-sticky funnel-shaped retreat in a corner or crevice. They do not use sticky silk to trap prey, relying on speed instead.
Eye Arrangement
Eight eyes of similar size arranged in two rows of four, appearing as a compact group at the front of the head.
Leg Characteristics
Notably long and hairy. They lack the thick spines of wolf spiders and the banding common in fishing spiders. The legs are designed for extreme running speed.
Venom & Safety Information
Venom Information
Neurotoxic/cytotoxic blend effective on insects but very low potency for humans. It is not considered medically significant.
Medical Significance
Harmless. A bite might cause minor localized redness or swelling similar to a bee sting, but symptoms usually resolve within hours. No special medical treatment is typically required.
Safety Recommendations
If found indoors, they can be easily relocated using a jar and a piece of paper. They pose no threat to pets or children and are best left alone to hunt pests.
Habitat & Behavior
Habitat & Range
Common in Europe and the Pacific Northwest of North America. Often found in homes, garages, sheds, and dark crevices in gardens.
Behavior & Temperament
Extremely fast runners and active nocturnal hunters. They are generally shy and will flee rapidly if disturbed. They are not aggressive toward humans and bites are rare.
Diet & Prey
Generalist predators feeding on various insects, including flies, beetles, and notably other spiders like the hobo spider. They ambush prey that wanders onto their sheet web.
Seasonal Activity
Active year-round indoors, but most visible in late summer and autumn when males wander in search of mates.
Description
The Giant House Spider is a common, large arachnid often seen scuttling across floors during the autumn mating season. While their size and speed can be startling, they are beneficial house guests that provide effective pest control.
Key Features
Large leg span, chevron patterns on the abdomen, and incredible running speed (one of the fastest spiders in the world).
Similar Species
Often confused with the Hobo Spider (Eratigena agrestis), which is smaller, or Wolf Spiders, which have much larger eyes and different hunting habits.
Life Cycle
Females produce multiple lens-shaped egg sacs containing 40-60 eggs each. They can live 2-3 years, which is longer than many other temperate spider species. Mating occurs in late summer and autumn.
Ecological Importance
Crucial for controlling indoor and outdoor insect populations. They act as top predators in the micro-ecosystems of basements and crawlspaces.
Conservation Status
Not evaluated by IUCN, but common and populations are stable/increasing in urban areas.
Interesting Facts
Until 2010, they held the Guinness World Record for top spider speed, clocked at 1.73 feet per second. They are known to actively hunt and displace the medically debated Hobo Spider.
Photography Tips
Flash is helpful to highlight the abdominal chevrons. Try to get a top-down (dorsal) shot of the cephalothorax to see the specific striping for identification.
Identified: 2026-06-30T21:21:18.672937