Black Widow vs Brown Widow

The quick tellBrown widows are tan to brown with an orange hourglass and leave spiky egg sacs. Black widows are black with a red hourglass and their egg sacs are smooth.
Black widow (Latrodectus mactans, L. variolus, L. hesperus)

Photo (Southern black widow): Kazvorpal, CC BY-SA 4.0, via Wikimedia Commons

Black widow

Medically significant · Latrodectus mactans, L. variolus, L. hesperus

  • Shiny black female with a round abdomen
  • Red hourglass or two red marks under the abdomen
  • Messy, strong web low to the ground, often in garages, wood piles and water meters
  • Males are small, brown and harmless

Size: 0.5–0.6 in. Habitat: Dark, dry, undisturbed spots: wood piles, sheds, crawl spaces, under outdoor furniture.

Venom affects nerves and can cause strong muscle pain and cramps. Deaths in the US are very rare.

Brown widow (Latrodectus geometricus)

Photo: Jade Fortnash, CC0, via iNaturalist

Brown widow

Painful, rarely serious · Latrodectus geometricus

  • Tan to dark brown female with an orange hourglass
  • Spiky round egg sacs that look like burrs
  • Webs under patio chairs, mailboxes and eaves

Size: 0.4–0.6 in. Habitat: Around houses in warm states; introduced and still spreading.

Related to the black widow, but its bites are usually milder.

Where each one lives

Alabama: both live hereAlaska: neitherArizona: Black widow onlyArkansas: Black widow onlyCalifornia: both live hereColorado: Black widow onlyConnecticut: Black widow onlyDelaware: Black widow onlyFlorida: both live hereGeorgia: both live hereHawaii: Brown widow onlyIdaho: Black widow onlyIllinois: Black widow onlyIndiana: Black widow onlyIowa: Black widow onlyKansas: Black widow onlyKentucky: Black widow onlyLouisiana: both live hereMaine: Black widow onlyMaryland: Black widow onlyMassachusetts: Black widow onlyMichigan: Black widow onlyMinnesota: Black widow onlyMississippi: both live hereMissouri: Black widow onlyMontana: Black widow onlyNebraska: Black widow onlyNevada: Black widow onlyNew Hampshire: Black widow onlyNew Jersey: Black widow onlyNew Mexico: Black widow onlyNew York: Black widow onlyNorth Carolina: both live hereNorth Dakota: Black widow onlyOhio: Black widow onlyOklahoma: Black widow onlyOregon: Black widow onlyPennsylvania: Black widow onlyRhode Island: Black widow onlySouth Carolina: both live hereSouth Dakota: Black widow onlyTennessee: Black widow onlyTexas: both live hereUtah: Black widow onlyVermont: Black widow onlyVirginia: Black widow onlyWashington: Black widow onlyWest Virginia: Black widow onlyWisconsin: Black widow onlyWyoming: Black widow only
Black widow: 48 states. Brown widow: 10 states. Both live in 9 states.

Side by side

Black widowBrown widow
DangerMedically significantPainful, rarely serious
Size0.5–0.6 in0.4–0.6 in
States4810
HabitatDark, dry, undisturbed spots: wood piles, sheds, crawl spaces, under outdoor furnitureAround houses in warm states; introduced and still spreading

Questions

How can you tell a black widow from a brown widow?

Brown widows are tan to brown with an orange hourglass and leave spiky egg sacs. Black widows are black with a red hourglass and their egg sacs are smooth.

Which one is dangerous?

The black widow: medically significant. The brown widow: painful, rarely serious. If you are not sure, keep your distance and do not handle it.

Where do both live?

Both live in 9 states: Alabama, California, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina and Texas.

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