Is the long-bodied cellar spider dangerous?

The long-bodied cellar spider is harmless to people. Harmless. The myth about deadly venom has been tested directly and is false. Note also that 'daddy long-legs' is used for three different animals: this spider, the harvestman, and the crane fly. None are dangerous.

How do you identify a long-bodied cellar spider?

Extremely long, thin, thread-like legs and a small elongated body. Vibrates rapidly in its web when disturbed, becoming a blur — a genuinely unique defensive behaviour.

Where do long-bodied cellar spiders live?

The long-bodied cellar spider is found across most of the United States, in habitats including basement, garage, indoors and bathroom.

Long-bodied Cellar Spider

Harmless

Pholcus phalangioides · also called daddy long-legs spider, skull spider, vibrating spider

The cellar spider is the subject of the most persistent spider myth in circulation: that it has the most powerful venom of any spider but fangs too short to bite. Neither half is true. Its venom is unremarkable, its fangs can pierce human skin, and the bite — when it happens — is a barely perceptible sting.

Bite risk: Harmless. The myth about deadly venom has been tested directly and is false. Note also that 'daddy long-legs' is used for three different animals: this spider, the harvestman, and the crane fly. None are dangerous.
Size: Body 7–10 mm. Tiny pill-shaped body on absurdly long, thread-thin legs spanning up to two inches.
Appearance: Pale tan or grey with a long, narrow, cylindrical abdomen and extremely long thin legs. The head-and-thorax has a faint dark mark sometimes said to resemble a skull.
Web: Loose, untidy, non-sticky tangle web in ceiling corners, basements and garages. Never cleaned or rebuilt, so it collects dust.
Found in: basement, garage, indoors, bathroom
Family: Pholcidae
Range: Most of the United States

How to identify a long-bodied cellar spider

Extremely long, thin, thread-like legs and a small elongated body.
Vibrates rapidly in its web when disturbed, becoming a blur — a genuinely unique defensive behaviour.
Dusty, untidy web that is never rebuilt.
Almost always indoors and up high.

How it behaves

Hangs upside down in the web and whirls violently when threatened. Preys on other spiders, including widows, and is worth leaving alone for that reason.

What the long-bodied cellar spider is confused with

One observation settles each of these.

Harvestman →

Harvestmen have a single fused body segment and no web at all. Cellar spiders have two body segments and always sit in a web.

If you think you were bitten

Most suspected spider bites are not spider bites. Studies of patients presenting with a “spider bite” repeatedly find that the large majority are bacterial skin infections — frequently MRSA — which need antibiotics rather than reassurance. A spreading, painful, pus-filled sore is far more likely to be an infection than a spider.
Wash it, ice it, and watch it. Clean the area with soap and water, apply a cold pack, and keep an eye on it.
Get medical care if the wound spreads or darkens, if you develop cramping, sweating, fever or severe abdominal pain, or if you are confident it was a widow or a recluse.
Bring the spider only if it is already dead and to hand. Do not go looking for it. Doctors treat symptoms, not species.

In the US, the Poison Help line is 1-800-222-1222. This site is a reference, not medical advice.

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