1. Classification & Appearance

Feature Description

Family Agelenidae (Funnel Weavers).

Body Size Large body size for a house spider. Females can reach up to 18.5 mm (0.73 in) in body length.

Leg Span This is where they earn their name. The leg span, especially of a mature male, can reach up to 75 mm (3 inches), making them one of the largest spiders commonly found in North American homes.

Colour Generally dark brown, black, or earthy tones. They have a conspicuously hairy body and legs.

Markings Often feature a lighter-coloured pattern on the sternum (the underside of the cephalothorax) and lighter spots along the abdomen. These markings are similar to, but often less defined than, their smaller cousin, the Barn Funnel Weaver (Tegenaria domestica).

Speed These spiders are famously fast. They were once considered the world's fastest spider, clocked at speeds of over 0.5 meters per second!

2. Habitat and Web

• Origin: Native to Europe, but introduced to North America, primarily via the Pacific Northwest, around 1900.

• Preferred Habitat: They are troglophiles, meaning they naturally prefer dark, protected, often damp environments like caves or under rocks and logs in forests.

• Indoors: They thrive in human structures because of the stable climate and protection from predators. They are most commonly found in basements, cellars, attics, garages, sheds, and behind large furniture—places that are dark and undisturbed.

• Web Structure: They build a distinctive sheet web (a large, flat, messy sheet of non-sticky silk) with a funnel-like retreat leading into a protected corner, crevice, or gap. The spider waits inside the funnel for prey to wander onto the sheet.

3. Diet and Hunting

• Diet: Generalist predators, consuming a variety of small invertebrates that stumble into their web, including flies, silverfish, and other spiders.

• Hunting: Once prey hits the web, the Giant House Spider rushes out of its funnel retreat to subdue the prey quickly with a venomous bite and wrap it in silk.

• Nocturnal Activity: They are primarily nocturnal, which is why they are often seen running across floors or trapped in sinks/tubs (after falling in while exploring) during the night.

4. Life Cycle

• Lifespan: Females can live for several years (typically 2 to 3, but sometimes up to 6) in the stable indoor environment. Males generally live for only about one year.

• Wandering Males: The late summer and autumn (late August to October) are when males reach maturity and leave the safety of their webs to actively search for females. This is the period when they are most likely to be seen suddenly running across a floor, bathtub, or sink.

• Egg Sac: Females produce multiple egg sacs, often hidden deep within the funnel retreat or in a dark crevice. Each sac can contain 60 or more spiderlings.

• Subsocial Young: The spiderlings will often remain together in the nest for about a month after hatching before dispersing.

5. Interaction with Humans

• Toxicity: The Giant House Spider's bite is not considered medically significant to humans.

• Bite Risk: They are very reluctant to bite, preferring to escape or flee. Bites usually only occur if the spider is aggressively handled, accidentally pinned against the skin, or trapped. A bite is often compared to a mild bee sting, resulting in localized, minor pain and slight swelling.