Brown Recluse Spider close-up


Of all the pest questions we answer, maybe the most common is, “is that thing dangerous?” The less we know about the pests we’re looking at, the scarier they seem. Let’s demystify the brown recluse spider in Michigan and help you feel safer about the spiders in your neighborhood.

We’ll cover what brown recluse spiders look like, brown recluse size, and how to avoid spider bites in Michigan. These are the pests that can pose a legitimate danger to people, pets, and property. With a little knowledge and maybe some professional help, you can keep spiders out of your home and avoid nightmares about creepy crawlers.

What is A Brown Recluse Spider?

The brown recluse spider (Loxosceles reclusa) is a venomous recluse spider native to the southeastern US.

Like most spiders, the brown recluse is considered very shy. They’ll go out of their way to avoid humans and would rather run away than act aggressively when confronted. Most brown recluses spend daytime hiding in dry, dark areas and hunt for food at night.

They build small, asymmetrical webs but don’t use these webs to hunt their prey. Instead, they hunt by lunging and using their venom to immobilize and kill it. Their webs are built out of sight and used as a retreat.

Brown recluse spiders are well-adapted to living indoors and will produce offspring in homes. Their eggs are off-white or tan colored and can be found in round or cone-shaped egg sacs. Each sac can contain up to 300 eggs. A good incentive for spider control measures!

Close up of a brown recluse spider

What Does A Brown Recluse Look Like?

Brown recluse spiders are uniformly tan to dark brown in color. Both the legs and torso lack any banding, spines, or mottling. All adult brown recluses have a distinctive dark “violin-shaped” mark on their backs which often prompts the nickname “violin” or “fiddleback” spider.

Unlike most spiders, brown recluses have six eyes instead of eight. The eyes are arranged in pairs – one in front and one on each side of their head. The spider’s legs are long, thin, and covered with fine hairs but not spikes.

Because of their size, brown recluse spider identification can be tricky. A pest control expert can help identify a brown recluse or any other spider species in your home.

How Big is A Brown Recluse Spider?

Brown recluse spiders measure around 1/4th to ½ inch (6 to 20 mm) long. That’s about the size of a quarter – not exactly the giant menace you may have pictured.

By comparison, an adult tarantula will grow to 4-6 inches in length. Roughly ten times brown recluse size.

Why Are Brown Recluse Spiders Dangerous?

The brown recluse is one of three North American spiders with significantly dangerous venom. Brown recluse bites are very, very uncommon, but when they happen, they can be extremely dangerous. Though 90% of bites heal quickly without any issues, 10% may lead to severe symptoms.

Brown recluse venom is necrotic, which means it can trigger cellular death whenClose up of a brown recluse bite injected into living tissue. This venom may inflict major tissue damage around the site of the bite, creating a large wound and scar.

Reactions to brown recluse bites are often delayed by 3 to 8 hours. The bite itself is painless. Hours after the bite, the victim may develop a blister or discolored lesion. The wound site will swell and become very painful. This process may be accompanied by vomiting, faintness, nausea, or cramping. Within 48 hours, necrosis may manifest. If that happens, the wound will turn purplish, then black in color. Eventually, the tissue may come away, creating a large wound. In this instance, seek professional medical help.

Again, it’s important to notjust how uncommon this is. Brown recluses very rarely bite humans, and even when they do those bites rarely develop into lesions.

Does Michigan Have Brown Recluse Spiders?

The brown recluse is native to the southeastern US. It’s not currently considered endemic to Michigan, and sightings here are quite rare.

As our climate changes, however, the brown recluse has been reported in southern Michigan more frequently. They are surprisingly hardy and can survive mild winters, especially if they have shelter. The brown recluse is most common in secluded, sheltered areas like rocky outcroppings, barns, forests, or wetlands.

Indoors, they’re most common in basements, attics, sheds, and other secluded locations. They may build webs in quiet corners, along awnings, or between boxes.


How Can I Avoid Spider Bites?

A doorway and stairs to a dark basementLuckily, spiders – especially the brown recluse – are shy. Most homes with brown recluses never report a bite. In most cases, a spider will run away vs become aggressive. If it does bite you, often it will be a “dry” bite where no venom is injected. The spider isn’t trying to kill you, it just wants you to go away.

The highest risk area for getting a spider bite is a crawl space or other restricted area where spiders are nesting. Your best prevention is to scope the area out before entering. Gloves, long sleeves and protective clothing can help.

Other areas to be aware of spiders: boxes, firewood stacks, laundry piles, shoes and other items that have been stored or untended for a long period of time. Spiders may have moved in and made these dark quiet areas their own.

What Kinds of Spiders Bite in Michigan?

Not many Michigan spiders have fangs capable of penetrating human skin. The two main spiders you have to worry about in Michigan are the brown recluse and the black widow. They are the only ones with a venom that is toxic enough to affect humans. Other biting spiders are the hobo spider and the wolf spider.

Every now and then there are anomalies in the animal kingdom that are difficult to explain like when a group of Mediterranean recluse spiders infested the University library at Ann Arbor.

Fast Solutions to Michigan Spider Problems

If you have questions about spiders where you live or are worried about how to be safe around spiders, give Griffin a call or contact us online. We’d be happy to address your concerns and prevent spider infestations in your home or business.

Dangerous Pests: The Brown Recluse in Michigan

Dangerous Pests: The Brown Recluse in Michigan Serving Kalamazoo & Grand Rapids

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