Brown recluse. Even the name alone has an ominous ring to it, but how can you be sure if the spider hiding in the deep shadows of your basement steps is the venomous beast or not? Knowing what is, and what isn’t, a brown recluse spider can determine whether you—and the spider—can live a long and carefree existence.

Step 1: Coloring

Brown recluse spiders are just that: dirty, dusty brown. If your spider has any other colors, it’s not a brown recluse. The brown recluse is pretty much devoid of all markings other than the darker brown fiddle shape on its body, too, so striped legs, darker legs, lighter body, or other changes in coloring do not a brown recluse make.

Step 2: Fiddle marking

The fiddle marking should be a darker solid brown than the rest of the dusty brown spider. If it has spots or is an entirely different color, your spider is not a brown recluse. The brown recluse’s fiddle isn’t a regular shape and may not look exactly like a Stradivarius to you, but it may look like something similar—a guitar, a banjo, a wine bottle—with the neck of the fiddle toward the tail end of the spider’s body the “bottom” toward the head. If you see a fiddle, banjo, or bottle in solid brown, you’re probably looking at a brown recluse and should take precautionary measures.

Step 3: Eyes

If your spider is close enough to you to see its head, try counting its eyes. Brown recluses only have six eyes where most spiders have eight. If you shine your flashlight onto the spider and only six little red dots come staring back at you out of the darkness, you’re definitely dealing with a brown recluse.

Step 4: Hairy legs

If the brown recluse was a human female, she’d have a serious need to shave her legs. The spider’s legs are covered in short, fine hairs that stick out at an angle. However, these hairy legs do not have spines. If you see spiny legs, hairy or otherwise, that’s not a brown recluse living under your stairs.

Step 5: Size

The brown recluse is a small spider, rarely larger than half an inch in size. If your spider resident is larger than that, you are definitely not sharing your home with a brown recluse.

Step 6: Habitat

As in all things real estate, location is key. The brown recluse is no exception. They prefer dry, dark, out-of-the-way, seldom disturbed places, so if your basement tends to be a bit damp or your stairs get a lot of traffic, you probably won’t find any brown recluses living there. Geography can play a part in the brown recluse’s choice of home, too. They prefer the drier areas of the Southeast, Southwest, and Midwest United States. However, that doesn’t necessarily mean brown recluses are a complete anomaly to your New England neighborhood, so take care.

While there is a danger of serious injury once bitten by a brown recluse, the spider itself is not aggressive. Most bites are accidental in that the human stumbles upon the spider. The brown recluse won’t actively hunt a human. Since the brown recluse is so small, it is not capable of biting through clothing, so your best protection after identification is to wear gloves, long sleeves, and heavy socks when working in areas where brown recluses are known to be residing. Stay safe!