Cellar Spiders: Habits, Eggs, Diet and Lifespan
By the Clark Pest Entomology Team | Last Updated: October 29, 2026
Key Takeaways
Cellar spiders are small, pale spiders with very long legs. They hang upside down in messy webs in basements, garages, closets and attics, and they live there all year. They shake when disturbed. They eat flies, gnats and mosquitoes, and sometimes other spiders. Penn State Extension says they aren't known to bite people.
Quick answer: A cellar spider is a pale tan or yellow spider with a body about 1/4 inch long and legs that can reach 2 inches. It builds a loose, tangled web in dark, quiet corners and lives indoors all year. Females carry their eggs in their jaws. Penn State Extension says they aren't known to bite people.
What a Cellar Spider Looks Like
Most homeowners find the long-bodied cellar spider, Pholcus phalangioides. Penn State Extension says females are 7 to 8 millimeters long and males about 6. That's a body under a third of an inch. The color is pale tan or yellow with a gray mark in the middle. The abdomen is shaped like a tube and runs about three times as long as it is wide.
The legs are what you notice first. An adult female's front legs are about 50 millimeters long, close to 2 inches. The University of Kentucky describes a small body held up by very thin legs.
Found one that isn't in a web? Compare it with the other spiders people mix it up with in our spider identification guide.
Is a Cellar Spider a Daddy Longlegs?
Often, yes. UC Riverside entomologists say the name daddy longlegs gets used for at least three different animals. The cellar spider is the only true spider of the three. Harvestmen and crane flies are the other two. A harvestman can't make silk, so a long-legged spider hanging in a web is a cellar spider. The spider identification guide has the full side-by-side.
Why Cellar Spiders Live in Your Basement and Garage
Cellar spiders like places that are dark, dry, quiet and protected, says the University of Maine. That describes basements, garages, closets, attics and sheds. The University of Kentucky adds pantries and barns. Penn State Extension says males and females both live in heated buildings all year.
Once they settle in, they tend to stay put. The University of Kentucky calls them slow movers that stay in one place. Penn State Extension says their numbers can grow large in a protected spot. Utah State University Extension says to look for messy webs near windows, over pipes and in corners. Check behind furniture too.
What Cellar Spiders Eat
Cellar spiders eat small insects. The University of Kentucky lists small moths, flies, gnats and mosquitoes. The spider hangs upside down in its web and waits for prey to get caught.
Sometimes the prey is another spider. When food is scarce, a cellar spider may leave its own web and visit a neighbor's. It taps the silk like a trapped insect. The owner comes to look, and the cellar spider eats it.
Eggs and Lifespan
A female lays 25 to 60 eggs at a time and wraps them in thin silk, says Penn State Extension. She doesn't hide the sac. She holds it in her jaws while she hangs in the web. The young hatch looking like tiny adults, per the University of Kentucky, and they shed their skin as they grow. A cellar spider takes about a year to mature. Adults can live two years or more.
Getting Rid of Cellar Spiders
UC IPM says insecticides won't give long-term control of spiders outdoors. Utah State University Extension points to habits instead. Cut down the other insects in and around the building. Vacuum spiders and webs inside and out, and keep doing it. Seal cracks, add door sweeps and repair screens. Clear clutter from the spots they like and trim plants that crowd the walls. The same page suggests sodium vapor bulbs for outdoor lights.
Looking for quick ways to clear webs or sort out other spiders? Start with the spider identification guide.
Sources: Penn State Extension, University of Kentucky Entomology, University of Maine Cooperative Extension, Utah State University Extension, UC Riverside Department of Entomology and UC IPM Pest Notes: Spiders.
Clark's Expert Insight
"If you touch a cellar spider web, the spider may start to vibrate, or dance. It's a defense move. The motion turns the spider into a blur, which makes it hard for a predator to see and grab. Penn State Extension describes the same circular shaking."
Frequently Asked Questions (FAQs)
Are cellar spiders poisonous? ▶
No. Cellar spiders do have venom glands, but a UC Riverside entomologist knows of no publication showing harm to people. Penn State Extension says they aren't known to bite people and aren't medically important. The University of Kentucky calls the deadliest venom story a widespread myth.
Why do cellar spiders shake in their webs? ▶
It's a defense move. Penn State Extension says a threatened cellar spider rapidly vibrates in a circle in its web. The motion makes it hard to see.
What do cellar spiders eat? ▶
Small insects. The University of Kentucky lists small moths, flies, gnats and mosquitoes. The spider hangs upside down in a messy web and waits for prey to get caught.
Do cellar spiders eat other spiders? ▶
Sometimes. The University of Kentucky says that when food is scarce, a cellar spider may enter another spider's web and tap it like a trapped insect. The owner comes to look, and the cellar spider eats it. The sources we checked don't name the spiders it eats, black widows included.
How long do cellar spiders live? ▶
About two years or more as adults. Penn State Extension says a cellar spider takes about a year to mature and can then live for two or more years.
How big do cellar spiders get? ▶
The body is small. Penn State Extension says females are 7 to 8 millimeters long and males about 6. The University of Kentucky puts the body at about 1/4 inch or less. An adult female's front legs can reach about 50 millimeters, close to 2 inches.
How many eggs do cellar spiders lay? ▶
Penn State Extension says a female lays 25 to 60 eggs in a cluster wrapped in thin silk. She carries the sac in her jaws while she hangs in her web.
Why do I keep finding cellar spiders in my house? ▶
Your building gives them what they like. The University of Maine says they favor dark, dry, quiet and protected places, and Penn State Extension says they live in heated buildings all year. Their numbers can grow large in a protected spot.
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