Spider Pest Authority
Identification, venom, and range data
Identify
Comparison

Black Widow vs. Brown Widow

The brown widow has displaced the southern black widow across much of the U.S. South. Both have hourglass markings; coloration and egg sacs are the cleanest separators.

Summary

Black widows are glossy jet-black with a red hourglass. Brown widows are tan with an orange-to-yellow hourglass and a spiky, tufted egg sac unlike any other widow.

Diagnostic traits

Black vs. Brown Widow - side-by-side
TraitSouthern Black WidowBrown Widow
Female body colorGlossy jet-blackTan with mottled bands
Hourglass colorBright red, completeOrange to yellow
Egg sacSmooth, off-whiteSpiky / tufted (diagnostic)
Bite severityLatrodectism, may need antivenomTypically milder, localized
HabitatSheds, woodpiles, electrical boxesPatio furniture, mailboxes, eaves

The bottom line

At-a-glance comparison

Southern Black WidowBrown Widow
ScientificLatrodectus mactansLatrodectus geometricus
FamilyTheridiidaeTheridiidae
♀ body8–13 mm7–12 mm
Leg span25–38 mm20–35 mm
Range23 U.S. states12 U.S. states
MedicalMedically significantModerate