Black Widow Spider Identification Guide
Recognize a black widow by its shiny black globose abdomen and red hourglass marking.
Read the full Black Widow Spider encyclopedia entry →
Key Visual Features
- Adult females have a body length of about 1/2 inch (not counting legs), with a shiny, jet-black, rounded (globose) abdomen
- A red hourglass-shaped marking on the underside of the abdomen, sometimes appearing as two separate triangles rather than a full hourglass
- Long, thin, black legs relative to the compact, rounded body
- A smooth, glossy cephalothorax (front body section) that is much smaller than the abdomen
- Males are much smaller and lighter in color, often tan or gray with light streaking and spotting, and look quite different from females at a glance
- Juveniles are patterned with white, tan, and orange markings that gradually darken toward the adult black-and-red look after each successive molt
Where and When You'll See Them
- Dark, undisturbed, sheltered spaces: woodpiles, garages, sheds, under rocks or debris, utility boxes, and crawl spaces
- Builds an irregular, tangled "cobweb" style web low to the ground or close to a sheltered surface, often near the entrance of its retreat
- Primarily nocturnal and reclusive, usually staying near its web retreat rather than wandering out in the open
- Egg sacs are round, papery, and off-white to tan, often attached within the web near the female
- Found across much of North America, especially in warmer southern and western regions
Similar-Looking Bugs
- False widow spiders have a similar rounded shape but are brown to purplish-brown with cream-colored markings and lack the true hourglass
- Brown widow spiders show a more mottled tan-brown pattern with an orange (rather than red) hourglass and distinctive spiky, textured egg sacs
- Other cobweb spiders share the messy web style but lack any hourglass marking and tend to be duller and less glossy overall
Quick ID Checklist
- Shiny black, rounded abdomen
- Red hourglass marking on the underside of the abdomen
- Long, thin black legs
- Small, irregular tangled web near ground level
- Found tucked into dark, undisturbed sheltered spots
Frequently asked questions
Does every black widow have a visible hourglass?
The marking's visibility can vary between individuals - it may be faint, reduced, or split into two triangles rather than a complete hourglass.
Do males look the same as females?
No, males are noticeably smaller, lighter colored, and show light streaking or spotting rather than the bold black-and-red female pattern.
Where are black widows typically found?
Look in dark, undisturbed corners such as woodpiles, sheds, garages, and crawl spaces where their tangled web can go unbothered.
What spiders get confused with black widows?
False widow and other cobweb spiders are the most common look-alikes, but they lack the true red hourglass marking on the abdomen underside.