Head to head
Black Widow Spider vs Brown Recluse Spider
The black widow and the brown recluse are the two spiders most feared in North America and the two whose bites most often need medical attention. They look nothing alike, their venoms work in completely different ways, and only one of them lives across most of the continent.
| Black Widow Spider | Brown Recluse Spider | |
|---|---|---|
| Identification | Glossy black, round abdomen, red hourglass underneath | Tan to brown, dark violin shape on the back, six eyes in three pairs |
| Body size | About 10 mm (female) | About 6–10 mm |
| Range | Throughout the warmer United States and much of the Americas | South-central United States only, roughly Kansas to Texas to Georgia |
| Web | Messy, strong, tangled web low to the ground | Loose, irregular retreat web in undisturbed clutter |
| Venom type | Neurotoxin (latrotoxin) | Cytotoxin (tissue-destroying enzymes) |
| Bite sensation | Often a pinprick, then spreading muscle pain and cramps | Often painless at first, then possible redness and a blister hours later |
| Worst-case outcome | Severe pain, sweating, raised blood pressure; deaths extremely rare | A slow-healing ulcer in a minority of bites; deaths extremely rare |
| Temperament | Bites defensively when trapped against skin | Extremely shy; bites when pressed in clothing or bedding |
| Antivenom | Available for black widow bites | None in routine use |
Black Widow vs Brown Recluse: common questions
Which is more dangerous, a black widow or a brown recluse?
Both are medically significant and both very rarely kill a healthy adult. The black widow causes worse immediate pain, spread through the whole body. The brown recluse can cause longer-lasting damage as a skin ulcer, but only in a fraction of bites, and its limited range means most of North America has no brown recluses at all.
How can I tell them apart?
A black widow is shiny, jet black, and round-bodied, with a red hourglass on the underside of the abdomen. A brown recluse is flat, uniformly tan-brown, long-legged, with a darker violin-shaped mark pointing back from its head. If a suspected recluse is shiny, patterned, or hairy, it is not one.
Are brown recluse spiders really everywhere?
No. Despite countless reported recluse bites across the United States, established populations are confined to the south-central states. Verified recluses outside that range are rare and usually single hitchhikers, and most bites blamed on recluses elsewhere turn out to be other conditions or other spiders.