Brown Recluse Spider

The brown recluse (Loxosceles reclusa) is a smooth, tan, quarter-sized spider with a dark violin shape on its back and, most reliably, six eyes arranged in three pairs. It lives mainly in the south-central and Midwestern US, hides indoors in undisturbed clutter, and bites only when trapped against skin.

How to identify a brown recluse

Most "brown recluse" sightings turn out to be something else. Spider experts at the University of California, Riverside spent years examining spiders mailed in as recluses from states where none live; the great majority were other species. Check these features in order:

1. Eyes. Six eyes in three pairs (dyads): one pair in front, one on each side, forming a semicircle. Nearly all other house spiders have eight. You need a magnifying glass or a zoomed phone photo, but this is the single best test.
2. Violin mark. A dark brown fiddle shape on the cephalothorax (front body section), with the neck of the violin pointing back toward the abdomen. Many spiders have dark marks here, so treat this as supporting evidence, not proof.
3. Uniform color. Abdomen evenly tan to grayish-brown and covered in very fine short hairs, so it looks smooth. No stripes, bands, spots or patterns on the abdomen or legs.
4. Legs. Long, thin, uniformly colored, with no spines visible to the naked eye.
5. Size. Body about 3/8 inch. Anything over about an inch of body length is not a recluse.

If your spider has striped legs, a patterned abdomen, thick hair or eight eyes, it isn't a brown recluse.

Brown recluse size

Brown recluse size is modest: an adult female's body is about 3/8 inch (9–10 mm), and with legs it covers about the area of a quarter. Males are similar in body length with slightly longer legs. Baby brown recluses are paler and smaller, sometimes only 1/16 inch at hatching, but they show the same six eyes.

Wolf spider vs brown recluse

The most common mix-up. Wolf spiders are hairy, robust, with striped or mottled brown-and-gray bodies and often banded legs. They have eight eyes, including two large ones that shine green in a flashlight beam. They run fast across floors at night. Brown recluses are smaller, smooth, plain and slow-moving by comparison. See brown recluse look-alikes and the wolf spider page.

Where do brown recluse spiders live?

Brown recluse locations are surprisingly limited. The native range centers on Missouri, Kansas, Oklahoma, Arkansas, Tennessee and Kentucky, extending into southeastern Nebraska, southern Iowa, Illinois, Indiana and Ohio, and south into northern Louisiana, Mississippi, Alabama, Georgia and north-central Texas. Other recluse species (Loxosceles spp.) occur in the desert Southwest.

Outside these areas (for example, California, Florida, the Pacific Northwest or New England) a breeding brown recluse population is rare; isolated finds are usually traced to furniture or boxes shipped from the range.

Inside the range, though, numbers can be striking. A single house may hold hundreds or thousands of recluses with residents rarely being bitten.

Where they hide in a house

Brown recluses are active at night and spend the day in dark, dry, undisturbed spots:

• cardboard boxes in closets, basements, attics and garages;
• behind and under furniture, baseboards, and in wall voids;
• inside stored clothing, shoes, bedding and towels left on the floor;
• under insulation and in crawl spaces;
• outdoors under rocks, bark, and in woodpiles and sheds.

Recognizing brown recluse cobwebs

The brown recluse web isn't a hunting snare. It's a small, irregular, loose tangle of off-white, slightly fluffy silk used as a retreat, typically in a corner of a box, behind a picture frame, or between stored items. Messy cobwebs high in room corners usually belong to cellar or house spiders instead.

How dangerous is a brown recluse?

Brown recluse venom can destroy tissue around the bite. Most bites are minor and heal by themselves. A minority develop a sunken, bluish center that becomes an ulcer and can take weeks to months to heal. Very rarely, especially in children, the venom causes systemic effects such as fever, rash, and the breakdown of red blood cells, which needs urgent care. Deaths are exceptionally rare.

Note that many skin wounds blamed on recluses (particularly outside their range) are actually MRSA infections and other conditions. If a wound is spreading, painful and hot, see a doctor regardless of the cause. Details and stages are on brown recluse bite.

How to get rid of brown recluse spiders

Recluses are among the harder spiders to eliminate, because they hide deep and tolerate starvation for months. A practical plan:

1. Declutter. Replace cardboard with sealed plastic bins, lift things off floors, and keep clothing and shoes off the floor.
2. Sticky traps. Place glue boards along walls, behind furniture and in closets. They catch a lot of recluses and show where activity is concentrated. Check and replace them monthly.
3. Move beds away from walls and remove bed skirts so spiders can't climb in; don't store items under beds.
4. Seal entry points: caulk cracks, fit door sweeps and screen vents.
5. Targeted insecticide. Crack-and-crevice residuals or dusts in wall voids and attics can help. Use only products labeled for spiders and follow the label. Foggers ("bug bombs") don't reach recluses in crevices and aren't recommended.
6. Shake out clothes, shoes and bedding that have been stored.

For established infestations, a licensed pest professional with experience in recluse control is worth it; expect a series of visits, often $300–$600 or more in total (approximate). More in how to get rid of spiders.