Learn to identify brown recluse and black widow

What to Do

Before taking action against spiders, learn to distinguish the two medically significant species from the many beneficial ones.

Brown recluse: Brown with a dark violin-shaped mark on the back. Uniquely has 6 eyes (three pairs) instead of 8. Body 6-20mm. Found in undisturbed areas — closets, attics, stored boxes. Range: south-central and midwestern US.

Black widow: Shiny black with a red hourglass marking on the underside of the abdomen. Found in garages, basements, woodpiles, and dark undisturbed areas. Several species across the US.

Why It Works

Most spiders are beneficial predators that eat pest insects. University extension services (UMN, UC IPM, Oregon State) consistently emphasize that eradicating all spiders is unnecessary and not recommended. Knowing which species are dangerous lets you respond proportionally.

Tips

• If bitten by either species, seek medical attention and try to capture or photograph the spider
• Brown recluse bites may not hurt initially but develop necrotic wounds over 24-72 hours
• Black widow bites cause immediate sharp pain followed by muscle cramps