Are Daddy Long Legs Poisonous? (The Myth, Settled)

No — daddy long legs are not poisonous, and the famous claim that they are “the most venomous spider in the world but their fangs are too short to break human skin” is a myth. It gets repeated endlessly, but it does not hold up. The confusion is made worse by the fact that two completely different animals get called “daddy long legs,” and only one of them is even a spider. Here is what is actually going on.

The myth, debunked

The myth makes two claims, and both fail. First, that daddy long legs are the most venomous spider on earth — there is no evidence for this, and their venom has never been shown to be unusually potent. Second, that their fangs are too short to pierce human skin — cellar spiders can in fact bite, and researchers (including the team at UC Riverside, which has tested exactly this) report the effect is at most a brief, mild sting with no medical significance. So the spider can bite, it just is not dangerous when it does. The dramatic version simply is not true.

Two different animals called “daddy long legs”

Part of why the myth persists is that “daddy long legs” means two different creatures. One is the cellar spider — a true spider with a small two-part body and very long, thin legs, the one you see in loose webs in garage and ceiling corners. The other is the harvestman (also called opiliones), which has a single oval body, even longer legs, and is not a spider at all — it has no silk and no venom glands. People lump them together because both have absurdly long legs.

Cellar spider vs. harvestman

Are daddy long legs dangerous to people or pets?

No. Neither the cellar spider nor the harvestman is a threat to people, dogs, or cats. A cellar spider could theoretically deliver a tiny, harmless nip if you really pressed one against your skin, and the harvestman cannot bite at all. There is no scenario in which a daddy long legs poses a danger to your household.

They are actually on your side

Cellar spiders are quietly useful: they catch and eat other insects, and they will even prey on other spiders — including, occasionally, ones you would rather not have around. A few cellar spiders in the garage are a sign the local bug population is being kept in check for you. If you can tolerate the webs, they are quietly doing your pest control for you, at no charge.

Should you get rid of them?

It is entirely cosmetic. If the dusty webs in the corners bother you, knock them down with a duster or vacuum and the spiders will move on or move out; keeping corners clear discourages them from rebuilding. If you would rather not deal with webbing at all, the same perimeter approach that handles other spiders works here — see our guide to getting rid of spiders, or read about the other common house spiders of California. For the science, UC Riverside’s spider research site covers the daddy-long-legs myth directly.

See our spider control process →

Daddy long legs FAQ