Where Do Brown Recluse Spiders Live? Real Range vs Myths

Which states have brown recluses?

The documented range of the brown recluse (Loxosceles reclusa) lies roughly south of a line running from southeastern Nebraska through southern Iowa, Illinois and Indiana to southwestern Ohio. In the south it reaches from central Texas east to western Georgia.

Reported bites come mostly from the core states. Within the range, recluses can be extremely common: entomologists have collected dozens in a single barn in an hour.

Where do brown recluses hide indoors?

Brown recluses like dry, dark, undisturbed spaces. In homes and other buildings they settle in:

• closets, wardrobes and piles of clothing on the floor
• attics, crawlspaces, basements and wall voids
• garages, sheds, barns and storage rooms
• cardboard boxes, behind furniture, and inside shoes or gloves that are rarely used

They are especially fond of cardboard, which may resemble the rotting bark they shelter under in the wild. By day they rest in small, messy retreats of irregular silk, and at night they wander out to hunt insects. Their pale, shed skins are often found before the spiders themselves.

Where do brown recluses live outdoors?

Brown recluses evolved long before houses existed. In the wild they live under rocks, loose bark, fallen logs and debris in dry, sheltered spots, in woodland and in more open, rocky country. Outdoors they also use woodpiles, stacks of lumber, stone walls and rubbish.

Even so, the species does particularly well around people. Buildings offer stable temperatures, shelter from rain and plenty of insects, and a few spiders brought in with firewood or boxes can become a large indoor population over the years.

The myth that brown recluses live everywhere

Many Americans believe the brown recluse lives in their state, wherever that is. Doctors in California, the Pacific Northwest, Florida and the Northeast diagnose “brown recluse bites” every year, and news stories repeat them.

Arachnologist Richard Vetter of the University of California, Riverside, tested the idea. From 2000 to 2005, people across the US mailed in spiders they believed were brown recluses. From California came nearly 600 specimens, and only one was a brown recluse, which had traveled there with a family that moved from Missouri. Seventeen others were native desert recluses from the desert regions of southeastern California. From states such as Missouri, Kansas and Oklahoma, by contrast, most of the spiders sent in really were recluses.

The conclusion was clear: recluses are almost entirely confined to their known range, but people believe they live nearly everywhere. Most suspected recluses turn out to be harmless spiders such as wolf spiders, cellar spiders and funnel weavers. The features that tell them apart are explained in what does a brown recluse look like?

The Kansas house with more than 2,000 recluses

The most famous evidence about brown recluses and people comes from an old house in Kansas, in the middle of the spider’s range. Over six months in 2001, the family living there collected 2,055 brown recluses from their 19th-century home.

The four family members had lived in the house for years and saw recluses regularly, yet none of them had suffered a serious bite. The researchers who reported the case in 2002 pointed out the lesson: if a house full of thousands of recluses produces no serious bites, then wounds blamed on recluses in states where the spider has never been found are very unlikely to be recluse bites. Read more in how dangerous is a brown recluse?

Why brown recluses do not spread

Many spiders disperse by ballooning: young spiders release silk threads that catch the wind and carry them for long distances. Brown recluses do not balloon, so spiderlings can only walk to nearby shelters.

People do move recluses around in furniture, boxes and stored goods, and over the past century single spiders have been found in many states outside the range. These hitchhikers occasionally build up a population inside one building, such as a warehouse, but such populations stay put and do not spread into the surrounding area. After decades of opportunities, the native range has stayed remarkably stable.

Could the range change in the future?

A 2011 study used climate data and the spider’s known locations to model where it could live. It suggested that as the climate warms, areas north of the current range could become suitable later this century. Whether recluses will actually spread there is uncertain, because their slow, walking dispersal limits how fast they can colonize new areas.

Recluse spiders outside the brown recluse range

The brown recluse is not the only recluse in North America. About ten other native species live mainly in the deserts and dry hills of the Southwest, such as the desert recluse (Loxosceles deserta) of California, Arizona and Nevada and the Texas recluse (L. devia). They usually live under rocks and in rodent burrows and rarely meet people. The introduced Chilean recluse (L. laeta) has small populations in parts of Los Angeles County, and the Mediterranean recluse (L. rufescens) has been found in isolated buildings in many states.

In Europe there are no brown recluses. The Mediterranean recluse is native to southern Europe and the Mediterranean region, where it lives in caves, cellars and buildings, but it is absent from northern Europe and the UK apart from rare imported spiders. For other recluses and widows in the US, see venomous spiders in the US.