Giant house spiders might sound scary, but they’re actually pretty interesting once you get to know them. These large, fast-moving spiders often appear in homes across the United States, especially during the fall. In this guide, we’ll explore everything you need to know about giant house spiders—from what they look like to how to keep them out of your house. Let’s dive into the world of this misunderstood creature!
What Does a Giant House Spider Look Like?
The giant house spider (scientific name: Eratigena atrica) earns its name from its impressive size. It’s one of the largest spiders you’ll commonly find inside homes in the United States. Adult giant house spiders typically have a leg span that can reach up to 4 inches (10 cm). That’s about the width of an average adult hand!
Their bodies are dark brown or muddy gray, and they have striped legs covered with tiny hairs, which help them move quickly across floors and walls. Some people confuse them with the wolf spider, but giant house spiders tend to be leaner, with longer legs and a more angular body.
When you spot one, it might look intimidating because of its size and speed—but it’s not out to get you. They usually run and hide the moment they sense humans nearby. In fact, many giant house spiders are more scared of you than you are of them.
Where Do Giant House Spiders Live?
Giant house spiders are most commonly found in dark, quiet areas. They love places where they won’t be disturbed. Inside homes, you’ll often spot them in:
- Basements
- Attics
- Closets
- Garages
- Behind furniture
Outdoors, they may live under rocks, in woodpiles, or in garden sheds. They prefer cool and damp environments, which is why bathrooms and basements are common hiding spots.
These spiders are native to Europe but have become quite common in the Pacific Northwest and other parts of the U.S. thanks to global travel and shipping. Once they find a comfortable space, they build messy sheet-like webs near floor level, especially in corners.
Are Giant House Spiders Dangerous?
This is probably the most common question people ask. And the good news? No, giant house spiders are not dangerous to humans or pets.
They may look big and scary, but they’re generally harmless. In fact, they can even help reduce the number of insects in your home by feeding on pests like flies, mosquitoes, and even cockroaches.
Let’s break this down further.
Do They Bite?
Yes, giant house spiders can bite, but it’s very rare. They usually only bite if they feel threatened or are handled roughly. Even then, their bites are not considered medically significant. A bite might cause mild irritation, like a mosquito bite, but most people don’t even notice it.
Can They Hurt Pets?
Your dog or cat is perfectly safe. Giant house spiders are not a threat to pets. If a curious cat paws at one, the spider will usually run away. In the rare event of a bite, the effects are minor and usually disappear on their own.
Are They Poisonous?
Here’s a common myth: “All big spiders are poisonous.” Not true. Giant house spiders are not poisonous to humans. While they do have venom (like all spiders), it’s only used to subdue their insect prey. Their venom is not strong enough to harm humans or pets.
What Do Giant House Spiders Eat?
Giant house spiders are natural pest controllers. They help keep your home free of other annoying bugs. Their diet includes:
- Flies
- Mosquitoes
- Moths
- Small beetles
- Ants
These spiders spin flat, messy-looking webs near the floor. They wait quietly in their retreat space at the edge of the web, then quickly rush out to grab any insect that gets caught.
Interestingly, giant house spiders don’t need to eat every day. They can go days or even weeks without food if necessary, though they prefer to snack regularly if insects are available.
How Do Giant House Spiders Get Inside Your Home?
Ever wonder how a giant spider ends up in your living room? These spiders usually enter homes in search of shelter, food, or mates, especially during the cooler fall months.
Here’s how they sneak in:
- Through open doors and windows
- Cracks in the foundation
- Gaps under doors
- Vents and pipes
- Boxes or items brought in from garages or sheds
They don’t mean to scare anyone—they just find your cozy house a perfect place to live!
How Can I Keep Giant House Spiders Away?
If you’d rather not share your space with these eight-legged guests, there are several things you can do to prevent them from coming inside.
Seal the Cracks and Gaps
Inspect your home for any small openings, especially around doors, windows, and vents. Use caulk or weather stripping to seal them up. Even the tiniest cracks can be an open door for a spider.
Keep Things Clean
Giant house spiders love cluttered, dark places. By vacuuming regularly and keeping storage areas tidy, you take away their favorite hiding spots. Also:
- Don’t leave food crumbs lying around—they attract insects, which attract spiders.
- Avoid stacking cardboard boxes or firewood indoors.
- Shake out clothes or shoes that have been sitting for a while.
How Long Do Giant House Spiders Live?
On average, a giant house spider lives about 1 to 3 years. Males usually die shortly after mating, while females can live longer if left undisturbed.
Interestingly, in controlled environments, some females have lived as long as 6 or 7 years! But inside most homes, their lifespan tends to be on the shorter side due to predators, lack of food, or human interference.
When Do Giant House Spiders Come Out?
You’ll see the most giant house spiders in late summer and early fall, typically from August to October. This is the spider mating season. Males come out of hiding to look for females, which is why they suddenly appear in hallways, bathtubs, or scurrying across your floors.
Outside of mating season, they stay hidden most of the time, quietly catching bugs and avoiding people. So if you spot one, it’s probably just looking for love—not trying to scare you!
The Bottom Line
Giant house spiders may look frightening, but they’re not dangerous, not aggressive, and not out to get you. In fact, they’re helpful little pest-control agents that keep other bugs in check.
Here’s a quick recap:
- They’re big but harmless.
- They rarely bite and aren’t poisonous to humans or pets.
- They eat annoying insects like flies and mosquitoes.
- They sneak in through small cracks or open windows.
- Keeping your home clean and sealed helps keep them out.
- You’ll mostly see them during the fall mating season.
So the next time you see a giant house spider, try not to panic. They’re just doing their thing—and chances are, they’re more afraid of you than you are of them!
