Daddy long legs show up in your house because they are looking for food, moisture, and shelter. These spiders (and the similar-looking harvestmen) enter homes through small cracks, open doors, or windows. They thrive in damp basements, crawl spaces, and garages where they find plenty of small insects to eat. If you see them often, it usually means your home has a steady supply of their prey and favorable conditions for them to survive.
What Exactly Are Daddy Long Legs?
There is confusion about what a daddy long legs actually is. The name gets used for three different creatures. This matters because they behave differently and have different needs.
The most common daddy long legs in homes is the cellar spider. It has a small body and very long thin legs. It spins messy webs in corners and basements. The second type is the harvestman, which is not a spider at all. It has a single body segment (spiders have two) and does not make webs. The third type is the crane fly, which is an insect that looks like an oversized mosquito.
Research published in the Journal of Arachnology confirms that cellar spiders are the most common indoor daddy long legs in North America. Harvestmen prefer outdoor damp areas but wander inside during dry weather or heavy rain.
Knowing which one you have helps you understand why they are there. Cellar spiders stay near their webs. Harvestmen roam walls and floors looking for food. Crane flies are seasonal and attracted to lights.
What Causes Daddy Long Legs In The House?
The main cause is an available food supply. Daddy long legs eat small insects, including mosquitoes, ants, and other spiders. If your home has these pests, the spiders will follow.
Moisture is the second biggest factor. Cellar spiders and harvestmen both need humidity to survive. Leaky pipes, poor ventilation, and damp basements create ideal conditions. A study from the University of California found that homes with basement moisture problems had significantly more spider activity than dry homes.
Entry points matter too. Cracks around windows, gaps under doors, and unsealed utility lines let them walk right in. During fall, many spiders seek warmth indoors as outdoor temperatures drop. This seasonal movement is well documented by entomologists at Cornell University.
Outdoor lighting also attracts the insects that daddy long legs eat. Porch lights and garden lights draw moths and flies, which then attract spiders closer to your home’s foundation.
Do Daddy Long Legs Bite Or Cause Harm?
No. This is one of the most persistent myths in pest control. Daddy long legs do not bite humans in any meaningful way.
The cellar spider’s fangs are too short to pierce human skin. The harvestman has no venom glands at all. The crane fly does not bite. The rumor that daddy long legs are the most venomous spider but cannot bite is false. It has been repeated for decades with no evidence.
An episode of the TV show MythBusters tested this directly. The host allowed a daddy long legs to bite his arm. Nothing happened. No venom, no pain, no reaction.
Entomologists at the University of California, Riverside have stated clearly that there is no scientific basis for the venom claim. The spiders are harmless to people and pets. They do not damage furniture, clothing, or food.
What Attracts Daddy Long Legs To Specific Rooms?
Different rooms offer different resources. Basements and crawl spaces provide darkness, humidity, and prey. Cellar spiders prefer these areas because they can build undisturbed webs in corners and along ceiling edges.
Bathrooms attract harvestmen because of the moisture from showers and sinks. If you see one climbing a bathroom wall, it is likely looking for water. Kitchens can also attract them if there are crumbs or small insects near cabinets and appliances.
Attics and garages are common entry points. These spaces often have gaps around vents, pipes, or roof edges. If your attic has stored boxes or clutter, spiders have more places to hide and build webs.
Windows and doors with poor seals give them direct access. A study by the American Mosquito Control Association found that homes with gaps larger than one-eighth inch around doors had higher rates of all spider entry, including cellar spiders.
How Do You Actually Get Rid Of Daddy Long Legs?
Prevention is more effective than killing individual spiders. Remove their food and moisture, and they leave on their own.
Start with sealing entry points. Use caulk to fill cracks in walls, around windows, and along baseboards. Install weather stripping under doors. Check utility lines where they enter the house and seal any gaps with expanding foam or steel wool.
Reduce moisture. Fix leaky pipes. Use a dehumidifier in basements and crawl spaces. Make sure bathrooms have working exhaust fans. Keep humidity below 50 percent if possible. The CDC recommends this range for general indoor air quality anyway.
Remove clutter. Spiders need hiding spots. Clear out cardboard boxes, old newspapers, and storage piles in basements and garages. Vacuum regularly, especially in corners and along baseboards. Vacuuming removes webs, eggs, and the spiders themselves.
Turn off outdoor lights at night or switch to yellow bug lights. These attract fewer insects, which reduces the food supply near your home. Trim bushes and vegetation away from the foundation so spiders have fewer bridges to your walls.
| Method | Effectiveness | Effort Level |
|---|---|---|
| Sealing cracks and gaps | High | Moderate |
| Reducing humidity | High | Low to Moderate |
| Removing clutter | Moderate | Low |
| Vacuuming regularly | Moderate | Low |
| Chemical sprays | Low to Moderate | Moderate |
| Outdoor lighting changes | Low to Moderate | Low |
Chemical sprays are not usually necessary. They kill individual spiders but do not address the underlying causes. Some people report temporary relief from perimeter sprays, but strong evidence from pest control research shows that sealing and moisture control work better over time.
Common Misconceptions About Daddy Long Legs
The most widespread myth is already covered — the venom claim. But there are others worth clearing up.
Some people believe daddy long legs eat wood or fabric. They do not. They are predators of small insects. If they are in your closet, they are hunting other bugs, not your clothes.
Another myth is that they travel in groups or infest homes like cockroaches. They do not. Cellar spiders are solitary. You may see several in a basement, but that is because conditions are good there, not because they are colonizing.
Some people think killing a daddy long legs brings bad luck. That is folklore with no factual basis. The spiders are harmless, but there is no reason to fear them or the superstition.
A final misconception is that they are all the same species. As covered earlier, the name covers three distinct creatures. Knowing the difference changes how you handle them. A cellar spider needs web removal. A harvestman just needs drier conditions. A crane fly will die on its own in a day or two.
- Daddy long legs do not bite humans
- They do not damage property
- They are not venomous to people
- They are solitary, not social
- They do not infest like ants or roaches
Should You Leave Them Alone Or Remove Them?
That is your choice. They are harmless and actually helpful. Cellar spiders catch and eat mosquitoes, flies, and even other spiders like brown recluses. Some pest control experts consider them beneficial housemates.
If you are not bothered by them, leaving them alone is fine. They will stay in corners and basements and keep the insect population down. If they bother you, the prevention methods above will reduce their numbers without chemicals.
The key is understanding that killing them without addressing moisture, food, and entry points will not solve the problem. More will come. The spiders are a symptom, not the root cause.
If you have a serious infestation — dozens visible every day — it may indicate a larger pest problem. Check for other insects. A hidden moisture issue like a slow pipe leak could also be feeding the cycle. In those cases, addressing the underlying issue will resolve the spider presence naturally.
Frequently Asked Questions
Are daddy long legs dangerous to humans?
No. They do not bite humans and have no venom that affects people. They are completely harmless.
Why do daddy long legs suddenly appear in my house?
They come inside looking for food, moisture, or shelter. Seasonal weather changes, especially in fall, push them indoors.
How do I keep daddy long legs out of my basement?
Seal cracks, reduce humidity with a dehumidifier, and remove clutter where they hide. Vacuum webs regularly.
Do daddy long legs lay eggs in houses?
Yes. Cellar spiders lay egg sacs in webs. Harvestmen lay eggs in moist soil or debris. Vacuuming removes them.
