You flip on the garage light and there it is: a pea-size body on legs that look far too long for it, picking its way across the wall. Someone has told you, probably at a cookout, that daddy longlegs are the most venomous spiders in the world and only their tiny fangs keep them from killing you. It's one of the most repeated bug stories in the country, and it's wrong on both counts.
No. The daddy longlegs most people mean, the harvestman, has no venom glands and no fangs, so it can't bite you. Cellar spiders, also called daddy longlegs, do carry a mild venom, but their fangs are usually too short to break human skin and no published case shows them causing toxic effects in people. Neither one is the "world's most venomous spider."
Which "Daddy Longlegs" Are You Looking At?
The name gets pinned on three unrelated animals. The University of California, Riverside's entomology department lists them as cellar spiders (family Pholcidae), harvestmen (order Opiliones) and crane flies (family Tipulidae). Only the first one is a true spider.
| Animal | What it is | Venom? | Can it bite you? |
|---|---|---|---|
| Harvestman (Opiliones) | Arachnid, not a spider | No venom glands | No fangs, no bite |
| Cellar spider (Pholcidae) | True spider | Yes, mild | Rarely; fangs usually too short for skin |
| Crane fly (Tipulidae) | Insect, a fly | No | No; many species lack mouthparts |
In the Carolinas and Virginia, "daddy longlegs" usually means the harvestman you find on porch rails, tree trunks and garage walls. If the thing is hanging upside down in a messy web in a corner, it's a cellar spider. If it flies, it's a crane fly.
Do Harvestmen Have Venom?
They don't. Clemson University's Home & Garden Information Center (HGIC) says harvestmen have no venom glands in their mouthparts and no fangs, so they "cannot (and will not) bite you." They also have no spinnerets, which means no silk and no webs.
What they do have is a smell. When a harvestman is grabbed, it releases a foul-smelling chemical that predators dislike. UC Riverside entomologist Rick Vetter describes their mouthparts as little pinchers used for tearing food, not fangs. The other trick is dropping a leg. The detached leg keeps twitching for a while, which buys the harvestman time to walk off on the other seven.
Here's how to recognize one:
- Body: a single oval, about 1/16 to 1/2 inch long, with no pinched waist
- Legs: eight, very long and thin; the second pair is the longest and works like a pair of feelers
- No web: you'll see it walking, not sitting in silk
Harvestmen eat small insects, including aphids, and scavenge dead insects and other organic debris. Clemson calls them generally beneficial predators, scavengers and decomposers.
Are Cellar Spiders Venomous?
Technically, yes. Unlike harvestmen, cellar spiders are true spiders, and UC Riverside notes they have fangs with venom ducts and glands. That's where the myth gets its grain of truth. But "has venom" and "dangerous to people" are very different claims.
The University of California Statewide IPM Program says cellar spiders are only marginally able to bite humans because their fangs are usually too short to pierce skin. Penn State Extension says the long-bodied cellar spider, Pholcus phalangioides, is not known to bite people and is not a medically important species. Vetter, who wrote UC's spider guidance, told UC Riverside he knows of no publication showing cellar spiders cause toxic effects in humans, calling them "definitely not the most toxic spider in the world."
You'll know a cellar spider by its habits. Penn State describes the web as an irregular mesh of threads, built in cellars, garages, warehouses and other dark, quiet spots, and in heated buildings year-round. Poke the web and the spider vibrates so fast it blurs. That's a defense, not an attack.
Where Did the "Most Venomous Spider" Myth Come From?
Nobody has pinned down the origin. Asked why the story persists, Vetter told UC Riverside he suspects someone said it once, nobody refuted it, and people love scary stories.
It has been tested, though. UC Riverside notes a 2004 MythBusters episode took on the claim, and a 2019 study by arachnologist Charles Kristensen found cellar spider venom injected into mice had far less effect than black widow venom. The "fangs too short" half of the legend doesn't save it either: harvestmen have no fangs at all, and cellar spiders have no record of harming anyone.
Why You See Daddy Longlegs Around Your House
Clemson says harvestmen are seen from May through November and are most common in fall, when they can gather in large clusters on trees and homes, usually around eaves and windows. If you've seen a tangle of long legs under an eave in Columbia or Greenville in October, that's what it was. In South Carolina and the rest of the Southeast, they can overwinter as adults and live up to two years.
Indoors, harvestmen stick to damp crawl spaces, unfinished basements and garages, and Clemson says they're rarely found in finished living space. Cellar spiders are different: Penn State says they live in heated buildings year-round, so from Charleston to Hampton Roads the garage, laundry room and storage closet are where you'll find their webs.
Neither damages your house. If you'd rather not share it:
- Vacuum or sweep them up. Clemson says a vacuum or broom handles most harvestmen on a structure, and UC IPM calls vacuuming an effective spider control that also removes webs.
- Change your outdoor lighting. UC IPM notes lights attract insects, which attract spiders. Keep fixtures away from doors and windows where you can.
- Seal the gaps. Caulk foundation cracks and gaps around windows and doors.
- Cut the clutter. Boxes, firewood and leaf piles against the house give both animals a place to hide.
- Use sticky traps indoors in garages and closets, placed where kids and pets can't reach them.
Skip the bug bombs. Clemson says chemical control of harvestmen is rarely necessary, and UC IPM says indoor spraying for spiders gives only temporary results without the housekeeping above. For more on where spiders settle in, see where spiders like to hide and why you see more spiders indoors every September.
The Spiders That Actually Matter
If you want to worry about a long-legged spider in the Carolinas or Virginia, worry about widows and recluses, not daddy longlegs. Our guide to brown recluse vs. black widow covers how to tell them apart, and our post on whether jumping spiders are poisonous covers another common worry.
UC IPM advises anyone bitten by a black widow to stay calm and seek medical advice, and to contact a doctor, hospital or poison control for any bite with an unusual or severe reaction. If you think you've been bitten by anything, talk to a medical professional rather than guessing from a photo.
When to Call a Professional
Daddy longlegs alone rarely justify a service call. Call when:
- Cellar spider webs keep coming back in the garage, basement or crawl space no matter how often you clear them
- Fall clusters of harvestmen are piling up around eaves, windows and doors every year
- You're seeing lots of spiders of any kind, which usually means lots of insects for them to eat
- You find a spider you can't identify, or one that looks like a widow or recluse
Our spider control service includes web removal and exterior barrier treatments for homes in South Carolina, North Carolina and Virginia. If you'd like someone to take a look, request a quote.
Key Takeaways
- Harvestmen can't bite you. Clemson HGIC says they have no venom glands and no fangs.
- Cellar spiders have mild venom but fangs usually too short to pierce skin, and no published case of harming people.
- Crane flies are flies, with no venom and often no working mouthparts.
- The "most venomous spider" story is a myth that has been tested and failed.
- Fall clusters are normal and harmless; a vacuum, a broom and better lighting handle most of it.
- Save your concern for widows and recluses, and see a doctor for any bite that worries you.
Sources: D. A. Oswalt, E. P. Benson, P. A. Zungoli and D. Coyle, "Daddy Longlegs" (HGIC 2418), Clemson Cooperative Extension Home & Garden Information Center; University of California, Riverside Department of Entomology, "Are daddy longlegs really the most venomous spiders in the world?"; S. Jacobs, "Longbodied Cellar Spider", Penn State Extension; R. S. Vetter, "Pest Notes: Spiders" (Publication 7442), University of California Statewide IPM Program.
Frequently Asked Questions
Harvestmen, the most common daddy longlegs, have no venom glands and no fangs. Cellar spiders, also called daddy longlegs, have a mild venom, but their fangs are usually too short to pierce human skin and they are not considered medically important.
A harvestman can't, because it has no fangs. A cellar spider can bite in theory, but the University of California says it is only marginally able to bite humans, and Penn State Extension says it is not known to bite people.
No. It is a myth. Harvestmen aren't spiders and have no venom, and a 2019 study found cellar spider venom had far less effect on mice than black widow venom.
Only the cellar spider is. Harvestmen are arachnids in a separate order, Opiliones, with a single oval body and no silk. Crane flies, sometimes called daddy longlegs, are insects.
Harvestmen have no venom or fangs, and cellar spiders are not considered medically important. If your pet has an unusual reaction after eating or mouthing any bug, call your veterinarian.
Clemson HGIC says harvestmen are most common in fall and can gather in large clusters on trees and homes, usually around eaves and windows. The clusters are brief and do not damage the structure.
Vacuum or sweep them up, move outdoor lights away from doors and windows, seal gaps, and clear clutter near the foundation. Clemson says chemical control is rarely necessary.
Photo credits: Photo: Ngan Nguyen on Unsplash (harvestman); Luis Fernández García, CC BY-SA 4.0, via Wikimedia Commons (cellar spider); Karlamalie, public domain, via Wikimedia Commons (brown widow).