Are Daddy Long Legs Poisonous? The Myth, and Three Different Animals
No: daddy long legs are not poisonous or dangerous to people, whichever of the three animals with that name you have found. Harvestmen, the round-bodied outdoor kind, have no venom glands and no fangs at all. Cellar spiders, the thin web-builders in basements, do have venom like nearly all spiders, but there is no evidence it harms humans. Crane flies, called daddy long legs in Britain, are insects that do not bite. The story that they are the world’s most venomous spider with fangs too short to bite is an urban legend.
The myth survives because one common name covers three unrelated animals, and each debunking usually deals with only one of them. This guide separates the three, explains where the legend breaks down on both counts (the venom and the fangs), and answers the practical questions: is it safe to touch one, what happens if one bites, and does a pet that eats one need a vet.
Three animals called daddy long legs
| Harvestman | Cellar spider | Crane fly | |
|---|---|---|---|
| Group | Order Opiliones, an arachnid but not a spider | Family Pholcidae, a true spider | Family Tipulidae, an insect (a fly) |
| Legs | 8 | 8 | 6, plus wings |
| Body | One oval, pill-like body, 2 to 10 mm | Two parts (head and abdomen), 6 to 8 mm in the longbodied species | Long, narrow, up to about 1 in (25 mm) |
| Eyes | 2 | 8, clustered | Compound eyes, like any fly |
| Silk and webs | None | Loose, irregular webs in corners | None |
| Venom | None: no venom glands, no fangs | Yes, but not shown to harm people | None; adults do not bite |
| Where you see it | Outdoors on walls, trunks, mulch; clusters near eaves in autumn | Indoors year round: basements, garages, ceiling corners | Warm months, especially spring and autumn |
| What it eats | Small soft insects, dead insects, plant juices, pollen | Insects and other spiders | Most adults eat little or nothing |
One cellar spider habit settles most doubts: Penn State notes that when threatened they vibrate rapidly in a circular motion in the web, becoming hard to see. A long-legged spider that shakes itself into a blur when you touch its web is a cellar spider.
The quickest field test comes from an evolutionary biologist’s rule of thumb and the anatomy behind it: if it is sitting in a web, it is a spider, because harvestmen make no silk. If it has one rounded body with legs radiating from it like a bead on wires, it is a harvestman. If it has wings, it is a crane fly.
Are daddy long legs poisonous? The myth, taken apart
The legend usually runs: daddy long legs have the most potent venom of any spider, but their fangs are too short to pierce human skin. Every part of that is wrong, and it is wrong differently for each animal.
Harvestmen: no venom at all
Harvestmen are not spiders. Ohio State University Extension states they do not produce venom, and the UC Riverside spider site puts it plainly: they do not have venom glands, fangs or any other mechanism for chemically subduing their food. University of Maryland entomologist Michael Raupp sums it up as no venom glands, no venom. Instead of fangs, harvestmen have small pincer-like mouthparts used to tear food apart. An animal with no venom cannot be the most venomous of anything.
Cellar spiders: venom, but weak and harmless to people
Cellar spiders (pholcids) are real spiders and do have venom, which they use on insects. The claim that it is unusually potent has never been shown. Rod Crawford at the Burke Museum notes that published work found pholcid venom to be unusually weak in its effect on insects, the opposite of the myth. Rick Vetter, a retired research associate in entomology at UC Riverside, has said he is not aware of any publication showing that pholcid spiders cause a toxic effect in humans.
The one experiment usually cited came from a 2004 television episode, later written up in a 2019 study, in which arachnologist Charles Kristensen injected mice with venom from cellar spiders or black widows. The black widow venom had the much more potent effect.
The fangs are not too short
The second half of the myth also fails. The Australian Museum reports that the cellar spider’s tiny fangs, about 0.25 mm long, proved capable of piercing human skin in a test on the US television show MythBusters, and the stinging sensation produced was very short-lived. So the fangs can, occasionally, get through skin; there is simply nothing dangerous behind them.
Crane flies: an insect, and not a biter
In Britain and Ireland, “daddy long legs” usually means a crane fly. The University of Kentucky’s entomology department is clear that crane flies do not bite humans or animals, and that many adult species do not eat at all. The US nickname “mosquito hawk” or “skeeter eater” is also a myth: adult crane flies are not predators and do not eat mosquitoes.
Where the legend may have come from
Nobody has traced the story to a single source. Vetter’s view is that it was something somebody said once, with never enough knowledge around to refute it, and people love scary stories. The Australian Museum suggests the myth probably grew from observations that cellar spiders kill and eat redback spiders, the Australian relative of the black widow. A thin, fragile spider that kills a widow sounds as if it must carry a fearsome venom. The museum adds that the venom is not actually that potent, even for insects.
What happens if a daddy long leg bites me?
For a harvestman, nothing, because it cannot bite in the venomous sense: it has no fangs and no venom. Clemson Cooperative Extension says simply that they cannot, and will not, bite you.
A cellar spider bite is rare. Penn State Extension describes the longbodied cellar spider as not known to bite people and not a medically important species. In the few informal tests on record, the result was a brief sting; Vetter recalls one researcher who had a small dark mark for a day or two. A crane fly does not bite at all.
Any bite mark that swells, spreads or worsens is a medical question, not an identification one, and should go to a doctor. Bites are poor evidence of what caused them, a point we cover in our guide to bite identification.
Which spider is the most poisonous?
Strictly, spiders are venomous (they inject), not poisonous (harmful to eat or touch). In the United States, the spiders that matter medically are the widow spiders and the recluse spiders: CDC’s workplace guidance names the black widow and the brown recluse as the venomous spiders of concern, and advises professional medical attention after a bite. Worldwide, the Australian Museum calls the Sydney funnel-web probably the most notorious of all spiders, though it records no deaths since antivenom was introduced. Cellar spiders and harvestmen are on nobody’s list. For telling a real recluse from its many lookalikes, see our spider identification guide.
Is it okay to pick up a daddy long legs?
Yes, with care for the animal rather than for you. A harvestman cannot hurt you, but it is fragile, and like many arachnids it can drop a leg when grabbed. A 2020 study in Scientific Reports by Escalante, Badger and Elias found that 69 per cent of harvestmen in one field population were missing at least one leg, and that harvestmen do not regenerate legs, even when lost young. The animals recovered their running speed within two days, but each lost leg is permanent.
Harvestmen also defend themselves chemically. Raupp describes glands along the body margin that release noxious quinones, a smelly secretion that deters predators. On your hand it is an odour, not a hazard, but washing your hands afterwards is sensible.
The kindest way to move one is to let it walk onto a sheet of paper or into a cup and carry it outside. A cellar spider can be moved the same way, or simply left where it is.
Are daddy long legs poisonous if eaten, or to cats and dogs?
Harvestmen have no venom, and cellar spider venom has not been shown to affect mammals in any meaningful way, so the published picture gives no reason to expect harm when a cat or dog swallows one. The harvestman’s defensive secretion is designed to taste bad to predators, so a pet may drool or paw at its mouth briefly. We found no extension or veterinary report of poisoning. As with anything a pet eats, persistent vomiting, swelling or lethargy is a reason to call your vet, not to wait.
When daddy long legs show up
The three animals peak at different times, which is another way to tell which one you have. Our analysis of iNaturalist research-grade records shows harvestmen as a summer and autumn animal, while cellar spider records stay much flatter across the year.
Harvestman records run at about half their usual share from January to April (index 41 to 48), jump to 131 in June and peak at 172 in October. That matches Clemson’s note that harvestmen gather in clusters on trees and homes, usually around eaves and windows, in the fall. Cellar spider records only range from 75 to 144, with the high point in October and November. Cellar spiders live indoors all year; the autumn rise most likely reflects people noticing them more as outdoor life winds down rather than a sudden invasion. These are records of where and when people photographed and identified these animals, not counts of infestations.
Daddy long legs in the house: what to do
Neither animal is a pest in the usual sense, and extension advice is consistent that chemical control is rarely needed.
- Harvestmen: Clemson notes they are beneficial predators and scavengers and that control is rarely necessary; a vacuum or broom removes the few that wander in. Ohio State lists aphids, caterpillars, beetle larvae, mites and slugs among their prey.
- Cellar spiders: a large population is mostly a housekeeping issue. Webs collect dust, and the spiders feed on other spiders and insects. Vacuuming webs and egg sacs is the practical fix. Penn State notes a female holds a cluster of 25 to 60 eggs, wrapped in a thin layer of silk, in her jaws, so removing a female with her egg cluster prevents a crop of young. They take about a year to mature and can live two or more years as adults, so a neglected corner fills up slowly rather than overnight.
- Fewer prey, fewer spiders: lots of cellar spiders usually means plenty of small insects to eat. Lowering basement humidity and sealing gaps, covered in our guide to bugs in the basement, removes their food.
- Crane flies indoors: they do not bite, and many adults do not feed at all. Let them out through an open window or door.
Spraying for spiders rarely solves a spider problem, because the next generation usually arrives from outside or hatches from sacs the spray never reached. Our spider control cost guide explains when paying for treatment makes sense, which for cellar spiders and harvestmen is almost never.
Other leggy things people mistake for daddy long legs
A fast, many-legged animal in a basement is usually a house centipede, which has 15 pairs of legs and which Penn State describes as harmless. A large, hairy spider running across the floor with no web is a wolf spider. A small, compact spider that hops and turns to watch you is one of the jumping spiders. None of these looks like a daddy long legs once you know the three body plans above.
Frequently asked questions
Are daddy long legs safe to touch?
Yes. Harvestmen have no venom glands or fangs, and cellar spiders are not known to bite people or to be medically important, according to Penn State Extension. The main risk is to the animal: harvestmen shed legs easily when grabbed and never regrow them. A harvestman may release a smelly defensive secretion, which is harmless but worth washing off.
Are daddy long legs spiders?
Only one of the three is. Cellar spiders (family Pholcidae) are true spiders, with two body parts, eight eyes and silk. Harvestmen (order Opiliones) are arachnids but not spiders: one oval body, two eyes, no silk and no venom. Crane flies are insects with six legs and wings. If the animal is sitting in a web, it is a cellar spider.
Can a daddy long legs bite kill you?
No. None of the extension or museum sources we consulted records a death or serious illness from any animal called daddy long legs. Harvestmen cannot bite venomously at all, crane flies do not bite, and the cellar spider’s venom proved far weaker than black widow venom when tested on mice. The few people bitten by cellar spiders on purpose described a brief sting.
Why are there so many daddy long legs in my house?
Cellar spiders build up where there is shelter, little disturbance and enough small insects to eat, which describes most basements and garages. Harvestmen wander in from outside, most often in late summer and autumn, when records of them peak. Removing webs, drying damp areas and sealing gaps reduces both, and neither calls for pesticide.
Sources
- University of California, Riverside, Spiders site: Daddy-long-legs (Opiliones and Pholcidae).
- UC Riverside Department of Entomology, Are daddy longlegs really the most venomous spiders in the world? (republished from Live Science), January 2022, with comments from Rick Vetter.
- Burke Museum, Spider Myths: Myth, the daddy-longlegs would kill you if only its jaws could pierce human skin, Rod Crawford.
- Ohio State University Extension, Ohio’s Natural Enemies: Harvestmen (also known as daddy longlegs), ENT-68, 2016.
- Clemson Cooperative Extension Home and Garden Information Center, Daddy Longlegs, HGIC 2418.
- University of Minnesota Extension, Harvestmen.
- Penn State Extension, Longbodied Cellar Spider, Steve Jacobs.
- University of Maryland, Bug of the Week: Daddy-longlegs, the most venomous of all spiders? Opilionids and pholcid spiders, Michael J. Raupp, 2022.
- University of Kentucky Department of Entomology, Kentucky Critter Files: Crane Flies, Blake Newton.
- Australian Museum, Daddy-long-legs Spider; and Sydney Funnel-web Spider.
- CDC National Institute for Occupational Safety and Health, Venomous Spiders.
- Escalante, Badger and Elias, Rapid recovery of locomotor performance after leg loss in harvestmen, Scientific Reports, 2020.
- Penn State Extension, House Centipedes.
- The Pest Control Brief analysis of iNaturalist research-grade records, pulled October 2026.
