Are Daddy Long Legs Really Venomous? The Myth Falls Apart Fast
- Give A Shit About Nature
- May 3, 2026
- Backyard Habitat
- 0 Comments
The myth goes like this: daddy long legs are the most venomous spider in the world, but their fangs are too small to pierce human skin. It’s the kind of thing that gets passed around at summer camps and backyard barbecues with total confidence. Britannica describes it plainly as scientifically baseless.
But here’s where it gets interesting. “Daddy long legs” isn’t one animal. It’s a casual nickname applied to at least three completely unrelated creatures, and the myth doesn’t even apply cleanly to any of them.
Three Animals, One Confusing Name
The three animals routinely called daddy long legs are harvestmen, cellar spiders, and crane flies. They look vaguely similar to a casual observer — long, spindly legs, often found indoors or in damp outdoor areas — but they’re not closely related, and they have meaningfully different biology.
Harvestmen (order Opiliones) are the ones most technically deserving the daddy long legs name. They’re arachnids, but not spiders. They have a single fused body segment rather than two, only two eyes, and no venom glands or fangs whatsoever. They can’t bite. The myth doesn’t apply to them at all, because there’s nothing to apply it to. What harvestmen do have is a chemical defense: when disturbed, they can release or coat themselves in a foul-smelling secretion that deters predators, but this is a far cry from lethal venom.
Cellar spiders (family Pholcidae) are the ones the myth is usually aimed at. These are true spiders, with two body segments, eight eyes, and yes, fangs with venom glands. They’re the pale, wispy spiders that build messy webs in basement corners and garage rafters. Research on pholcid spider venom has found it to be relatively weak by spider standards, and there’s no documented case of a cellar spider bite causing a medically significant reaction in humans. Their fangs can likely pierce skin, but they essentially never do, and when they have, the result is described as roughly equivalent to a minor bee sting at worst.
Crane flies are insects, not arachnids at all. Many species lack functional mouthparts entirely as adults, meaning they literally cannot bite. The myth doesn’t touch them either.
Where the Myth Actually Came From
The cellar spider’s reputation for taking down dangerous spiders, including black widows, is real. People observed that and drew an obvious but wrong conclusion: if it can kill a black widow, its venom must be even more potent. What research has actually shown is that cellar spiders subdue other spiders using silk and movement, not through superior venom. The venom is mild. The hunting strategy is what makes them effective against larger, more dangerous spiders, and that’s a much less dramatic story than the myth, so the myth won.
The “fangs too short to bite” part is also wrong. Cellar spider fangs are short, but arachnologist Rick Vetter of UC Riverside, who has studied this question directly, found no evidence to support the fang-length explanation as the reason they don’t bite humans. They just don’t tend to bite, and when they do, nothing much happens.
What They’re Actually Doing in Your Garden
Harvestmen are quiet and underappreciated garden residents. They’re scavengers, feeding on decomposing plant material, dead insects, fungi, and occasionally small live prey. They’re part of the cleanup crew, breaking down organic matter in the same category of ecological function as leaving leaf litter in place rather than raking it bare. They don’t build webs, they don’t bite, and they don’t damage plants. Finding them under logs, in garden beds, or around damp areas is a normal sign of a functioning soil ecosystem.
Cellar spiders in your home or garage are doing something useful too: catching and eating other insects. The scrappy, irregular webs they build in corners aren’t pretty, but they’re working. Leaving them alone costs nothing and keeps the insect population in the corners of your house lower than it would otherwise be.
Crane flies tend to alarm people because they look like enormous mosquitoes. They’re not. Adult crane flies typically don’t feed at all, or feed on nectar. Their larvae live in soil or decaying matter, and while some species can affect lawns in large numbers, the adult flying around your porch light is not a threat to anything.
The broader point: all three of these animals are harmless to humans, and two of them are actively doing useful work in your yard. Yards that support diverse insect and invertebrate communities tend to have better ecological function overall, and the presence of harvestmen is one small indicator of a healthy, intact soil layer.
FAQ
Can daddy long legs bite humans? It depends a little bit on which animal you mean. Harvestmen have no fangs or venom and cannot bite. Crane flies cannot bite either. Cellar spiders have fangs and technically can bite, but virtually never do, and the venom is considered medically insignificant to humans.
Are harvestmen the same as spiders? No. Harvestmen are arachnids in the order Opiliones, but they lack the two-body-segment structure, silk glands, and venom glands of true spiders. They’re more distantly related to spiders than most people assume.
Why do cellar spiders wrap up black widows if their venom is weak? They rely on silk and movement to subdue prey rather than venom potency. A cellar spider can entangle a black widow in web before the black widow can deliver a defensive bite, which is a hunting strategy rather than a sign of superior toxicity.
Are crane flies harmful to gardens? Adult crane flies are essentially harmless. Some crane fly larvae (leatherjackets) can cause lawn damage in large numbers by feeding on grass roots, but this is species-dependent and not something the adults themselves cause.
Should I remove daddy long legs from my home? There’s generally no reason to. Harvestmen outdoors are part of a functioning decomposer community. Cellar spiders indoors catch other insects. None of them bite, sting, damage structures, or pose any health risk.
