Is the grass spider dangerous?

The grass spider is harmless to people. Harmless. Not inclined to bite and of no medical significance.

How do you identify a grass spider?

Two long spinnerets sticking out at the back like a pair of tails — very distinctive at close range. Two bold dark stripes running down the head-and-thorax.

Where do grass spiders live?

The grass spider is found across most of the United States, in habitats including garden, grassland and garage.

Grass Spider

Harmless

Agelenopsis species · also called funnel weaver, sheet web spider

Grass spiders make the sheet webs that appear all over a lawn on a dewy autumn morning. They are among the fastest spiders in North America over short distances, which is unsettling but of no consequence, and they are entirely harmless.

Bite risk: Harmless. Not inclined to bite and of no medical significance.
Size: Body 10–20 mm. Body about a thumbnail with long legs.
Appearance: Brown with two bold dark lengthwise stripes on the head-and-thorax, and a pair of long, finger-like spinnerets projecting visibly from the rear of the abdomen.
Web: The horizontal sheet webs with a funnel at one corner that cover lawns, hedges and ground cover on dewy mornings. Not sticky — it works by tripping insects.
Found in: garden, grassland, garage
Family: Agelenidae
Range: Most of the United States

How to identify a grass spider

Two long spinnerets sticking out at the back like a pair of tails — very distinctive at close range.
Two bold dark stripes running down the head-and-thorax.
Flat non-sticky sheet web with a funnel retreat, usually outdoors in grass or shrubs.
Extremely fast, but only over short distances.

How it behaves

Waits in the funnel and rushes out when an insect trips the sheet. Rarely comes indoors except by accident.

What the grass spider is confused with

One observation settles each of these.

Hobo spider →

Hobo spiders lack the bold stripes and prominent tail-like spinnerets, and are indoor spiders in a much smaller range.

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.

Not sure it was a grass spider? Identify it step by step →