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Spiders & Scorpions

Giant House Spider

Eratigena atrica

Danger Level: 2/5Updated September 2026 · Boise, ID

IdentificationHow to Identify Giant House Spider

Quick Answer

Giant house spiders are among the largest spiders in Idaho, with leg spans up to 75mm (3 inches). They're brown with mottled darker markings and build funnel webs.

Full identification notes

They're often confused with hobo spiders but are larger with banded legs and more distinct markings.

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Giant House Spider Behavior & Habits

Understanding how giant house spider behave helps prevent infestations

Giant house spiders are fast runners that build funnel webs in dark corners.

More about their habits

Males wander in late summer/fall seeking mates, leading to increased indoor sightings. Despite their alarming size, they're shy and prefer to flee rather than bite. They're actually competitors of hobo spiders.

Giant House Spider Risks & Dangers

What giant house spider can do to your health and property

Health Risks

Giant house spiders rarely bite, and bites are not medically significant.

Property Damage

No property damage.

Full health and property details

Health Risks

Reactions are comparable to a minor bee sting. Their large size makes them frightening, but they're not dangerous.

Property Damage

Their webs can be unsightly in corners and crevices.

Signs of Giant House Spider Infestation

Look for these indicators in your home

Signs You Have Giant House Spider

What homeowners spot first

  1. Large funnel webs in dark corners
  2. Fast-moving large spiders, especially at night
  3. Increased sightings in August-October
More signs to look for
  1. Banded legs visible on close inspection
  2. Webs in basements, garages, and bathrooms

Giant House Spider in Boise & the Treasure Valley

We see most giant house spider calls in September and October, when wandering males show up in basements and garages looking for mates.

More on what we see locally

They're especially common in older Boise neighborhoods with full basements (North End, East End, Boise Bench) and in Garden City and Meridian garages with damp corners. The good news: they actually outcompete and prey on hobo spiders, so a few in your basement may be keeping the more dangerous ones out. Our technicians often find them sharing dark corners with cellar spiders along the foothills, where cooler nighttime temps push them inside.

Our Solution

How We Handle Giant House Spider

What our approach looks like

Giant house spider control involves treating harboring areas with residual products and reducing prey populations.

Our full approach

Sealing gaps around doors and windows on your end helps too. Because they help keep hobo spiders in check, we usually focus on keeping them out of living areas rather than wiping them all out.

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How to Prevent Giant House Spider

Steps you can take to reduce the risk of infestation

  1. Seal gaps around doors and windows
  2. Use door sweeps
  3. Reduce clutter that provides hiding spots
More prevention steps
  1. Regular cleaning removes webs and eggs
  2. Sticky traps along baseboards

Giant House Spider Questions Answered

Common questions about identification, prevention, and treatment

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Is this a hobo spider or giant house spider?

Quick answerGiant house spiders are larger with distinctly banded legs.

Hobo spiders have solid brown legs without bands. Giant house spiders are actually harmless and prey on hobo spiders.

Why am I seeing so many of these in September and October?

Quick answerThat is mating season.

Male giant house spiders leave their funnel webs and wander through basements, garages, and bathrooms looking for females. You are not seeing more spiders overall, just the males that are normally hidden. Sightings usually drop off by November.

Should I kill them or leave them alone?

Quick answerIn Boise, leaving a couple in undisturbed basement corners is actually helpful.

They prey on hobo spiders, which carry a much worse reputation. If you want them out of living areas, seal gaps around doors and windows, knock down funnel webs, and call us at (208) 297-7947 for a perimeter treatment that keeps both species outside.

Think You Have Giant House Spider?

Call and we'll talk through your options. We usually get out within 24 to 48 hours.

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