Spiders
Are there brown recluse spiders in Michigan?
A few, and almost certainly not the one in your basement. Michigan State University has confirmed brown recluses in a handful of homes and buildings, all carried in from farther south. Here is how rare they are, how to tell one from the spiders people mistake for it, which Michigan spiders do bite, and why most "recluse bites" are something else.
By Nick Russler, ownerLicensed and insured in MichiganPublished
The short answer
- Native to Michigan
- No
- Found here
- A few homes and buildings
- How they arrive
- In boxes and suitcases
- Photos that were one
- 7 of about 700
- Easiest tell
- 6 eyes in 3 pairs
- Bites that self-heal
- About 90 percent
Michigan is outside the brown recluse's native range. Michigan State University Extension has recorded it in 10 counties, including all four we serve, but each find was a small, isolated population that arrived in someone's boxes or luggage. Of about 700 photos Michiganders sent MSU's entomologist as possible recluses, only seven were. In MSU's words, the vast majority of Michiganders will never come within half a mile of one. Most of the spiders people mistake for it are wandering hunting spiders.
Prefer to listen? One minute.
The short version, read aloud. Read by a synthetic voice, not one of our technicians.
A big brown spider ran across the basement floor, you looked it up, and now every picture on your phone says brown recluse. Or someone in the house has a sore that will not heal, and the word came up.
Both are good reasons to get the facts straight. The short version is reassuring, and it comes from the entomologists who have looked at the spiders Michigan sends them.
How rare brown recluses are in Michigan
The brown recluse lives in about 20 states, with the most around Kansas, Oklahoma and Missouri, according to the University of California, Riverside. Michigan is not one of them. But the spider travels well, hiding in boxes, suitcases and shipped goods, and every so often one arrives.
MSU Extension's 2018 count had it in 10 Michigan counties: Genesee, Hillsdale, Ingham, Kent, Lenawee, Livingston, Oakland, Shiawassee, Washtenaw and Wayne. One was found in a building on the University of Michigan campus in Ann Arbor, which MSU put down to the number of people coming and going from all over the country. One Kent County find came from a family just back from a trip to Missouri.
That list sounds worse than it is. MSU is clear that these were rare, isolated populations, not spiders spreading north on their own. The best way to see how rare is to count the photos people sent in.
What Michiganders sent MSU as a brown recluse
About 700 photos and specimens over 14 months, from MSU Extension (2018).
How to tell a brown recluse
Look at the eyes before anything else. Most spiders have eight eyes in two rows of four. Brown recluses and their relatives have six eyes, in three pairs, set in a U shape at the front, per UC Riverside.
- Size: no more than half an inch in body length, according to UC Riverside's Rick Vetter.
- The violin: a dark brown violin shape on the front part of the body.
A spider with eight eyes, or a body well over half an inch, is not a brown recluse. That rules out most of the big brown spiders in Michigan basements straight away.
The spiders people mistake for one
MSU's entomologist ranked the spiders in the photos Michiganders sent as possible recluses. Nearly all of them are wandering hunters that do not spin a web to catch prey, which is why they turn up walking across floors.
| Rank | Spider | Worth knowing |
|---|---|---|
| 1 | Dark fishing spider | Tied for the most mistaken |
| 1 | Nursery web spider | Tied for the most mistaken |
| 3 | Grass spider | Common around yards and gardens |
| 4 | Wolf spider | Up to almost an inch long |
| 5 | Running crab spider | A fast, flat hunter |
| 8 | Yellow sac spider | Common in homes, and it does bite |
Dark fishing spider: the most common mix-up
Northern black widow: a native biter
The Michigan spiders that do bite
Michigan has about 500 native spider species, and MSU counts three as medically important:
- The northern black widow, a native, glossy black spider.
- The yellow sac spider, small and pale, very common in and around homes. MSU says some call it a "recreational biter", meaning it will bite without much reason.
- The northern cobweb spider, to a lesser degree. MSU notes its bite can look like a recluse bite.
None will aggressively chase you down the hall to bite you.
Michigan State University Extension
Is that sore a spider bite?
Often it is not. UC Riverside and dermatologists who treat recluse bites in Missouri found that about 40 medical conditions get mistaken for brown recluse bites, several of them serious bacterial infections. Their rule of thumb: a real recluse bite is whitish blue or purple, flat, and heals within three months. A wound that is red, raised, or lasts longer is probably something else.
Michigan has its own example. MSU tells of a woman whose bite was diagnosed at a hospital in Ann Arbor as a brown recluse bite. She had caught the spider in the act. It was a yellow sac spider.
If you are bitten, or a wound will not heal
The CDC's first aid for a spider bite: stay calm, wash it with soap and water, put a cold, damp cloth or ice on it, and raise it if you can. If it is safe, catch or photograph the spider, since it helps with treatment. Get medical attention for any bite that gets worse. Do not let anyone rule out an infection because the word "recluse" came up.
If you think you found one
Catch it in a jar or take a sharp photo from above that shows the eyes and the back. Count the eyes if you can. MSU's entomologist has identified hundreds of Michigan spiders from photos and specimens like that, and the odds are strongly in your favor.
A real reproducing population is rare, but it does happen: MSU tells of one home in Lenawee County where spiders of every age were found. If you are finding the same six-eyed spider again and again, that is worth confirming.
For the everyday spiders, the ones that are really in most Michigan basements, the problem is webs and numbers, not danger. More than 90 percent of a spider's diet is insects, per MSU, so a house with a lot of spiders usually has a lot of something for them to eat.
Tired of the webs and the big ones in the basement?
We clear webs from the eaves and windows, treat where spiders hide and hunt, and cut down the insects that feed them. Spiders are covered by Honorable Shield. Quotes are free.
You do not need us for one spider. You might want our spider control if webs keep coming back on the eaves and in the window wells, or if there is always one in the basement.
Common questions
Are brown recluse spiders in Michigan?
A few. MSU Extension has confirmed them in 10 Michigan counties, including Washtenaw, Livingston, Oakland and Wayne, but only as rare, isolated populations carried in from farther south. Michigan is outside their native range.
What spider is most often mistaken for a brown recluse in Michigan?
The dark fishing spider and the nursery web spider, tied for first in MSU's count of photos people sent in. Both are big, harmless hunters.
How can I tell a brown recluse from a wolf spider?
Count the eyes. A brown recluse has six eyes in three pairs. A wolf spider has eight. Wolf spiders are also often striped and can be almost an inch long, while a brown recluse body is no more than half an inch.
Are black widows in Michigan?
Yes. The northern black widow is native and one of the three Michigan spiders MSU calls medically important.
Which Michigan spider bites people the most?
The yellow sac spider is a good bet. MSU says it is very common in and around homes, and some call it a recreational biter.
How dangerous is a brown recluse bite?
Usually not very. UC Riverside's Rick Vetter says about 90 percent of recluse bites heal on their own, about 10 percent leave a slow-healing wound, and under 1 percent cause a serious whole-body reaction.
Do spiders chase people?
No. MSU says no Michigan spider will aggressively chase you. The CDC's advice is simply to shake out clothing, shoes and towels that have been sitting unused before you put them on.
About this page
Written by Nick Russler, owner of Honorable Pest Control in Ann Arbor, Michigan. The Michigan records and look-alike ranking come from Michigan State University Extension, the identification and bite facts from the University of California, Riverside, and the first aid from the CDC. All were read on September 26, 2026. If something here is out of date or wrong, tell us and we will fix it.
Sources
- Michigan State University Extension, Don't panic over brown recluse spiders in Michigan (2018)
- University of California, Riverside, Department of Entomology, No, That's Not a Brown Recluse Spider Bite (2017)
- University of California, Riverside, Spider Research, Myth of the Brown Recluse
- US Centers for Disease Control and Prevention, NIOSH, Venomous Spiders
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