The Ultimate Guide on How to Tell if a Spider Is Poisonous

Posted by Remedy on

There are an estimated 3,500 species of spiders in the United States. Scientists suspect there are more spiders in the world than the ones we know about. The good news is most of them are not dangerous. Some can't even bite humans because their fangs are too small.

The dangers of spiders are exaggerated. When spiders do bite, it's because they feel threatened. It's often easier to coexist with spiders than get rid of them.

You shouldn't ignore poisonous spiders in your home, though. We'll discuss how to tell if a spider is poisonous here so you can be sure.

Treat Any Bite At Once

Poisonous spiders are rare, but you should still treat any suspected spider bite as soon as you notice it. Venomous bites often aren't fatal, but some people can be allergic, which can lead to medical emergencies.

Even if the bite isn't venomous, it's worth getting it checked out. Knowing what kind of spider you're dealing with is worth it in the long run. It might alert you if something's off.

For instance, a high number of spiders inside could be a sign of an insect infestation. Spiders go where their prey is, so spiders coming inside might mean insects are inside.

Know Your Spiders

You may have heard the rhyme about identifying poisonous snakes based on coloring. There's no such standard for spiders. The best strategy with spiders is to learn about poisonous spiders and work from there.

Where do you live? Most poisonous spiders in the United States are regional, so if you're in California, you probably won't find any brown recluse spiders.

Take note of where you found the spider. Most spiders make their homes in dark, enclosed areas, such as firewood stacks, basements, or the small spaces between furniture and walls. This is because most poisonous spiders are web-weavers. Those who hunt, like wolf spiders, jumping spiders, and tarantulas, use speed and other natural abilities, so they have less trouble escaping danger.

Types of Venomous Spiders

Experts believe around 30 of the tens of thousands of spider species in the world are capable of delivering lethal amounts of venom to human beings. Out of these species, a handful live in the US. Let's discuss a few of them.

Brown Recluse Spider

The Brown Recluse spider is native to the Central and Southeast United States. Their range encompasses areas with central Texas as its western edge, and Georgia as its eastern edge. From there, it extends as far north as Nebraska. A simpler rule is east of Texas and south of Lake Michigan.

One way to identify a Brown Recluse spider is by looking for a violin-shaped mark on its abdomen. This method isn't always reliable, though, because the marking darkens with age. If you can't find one, it could mean the spider is a juvenile.

It's also difficult to tell what shape a marking is on a creature so small. This is part of the reason behind the panic. People have gotten scared because they found a brownish spider with some sort of marking on it. This describes a lot of spiders, and chances are the creature isn't a Recluse.

A more reliable test is to look at the creature's eyes. Most spiders have eight eyes arranged in four pairs. A Brown Recluse is unique because it only has six eyes. A few types of spiders have only six eyes, but it's a rare enough trait that a six-eyed spider in the proper range is likely a recluse. If you want to make sure, look at the positioning of the eyes. A brown recluse has one pair of eyes in the center and a vertical pair on either side.

Black Widow

This spider gets its name from its coloring, and the observed behavior of the female eating the male after mating. However, the Widow is a misnomer. What scientists didn't realize when they first observed the spider was the enclosed space and limited food skewed the results of their studies.

In the wild, this behavior is rare. Males prefer partners who've recently eaten and will wander off after mating. Unlike the Recluse spider, widows have a distinctive appearance. They are black with a bright red hourglass mark on their abdomen.

There are a few different species of Black Widow, but the worst is the Southern Black Widow, which is endemic to the Southwestern US. Like the Recluse spider, Black Widows are timid and prefer to avoid humans. Some of their favorite nesting spots are under roof eaves, in wood piles, and in similar confined, neglected spaces.

Hobo Spiders

While the Southwest United States has Black Widows, the Northwest has Hobo Spiders. Hobo Spiders are a type of spider known for having yellow markings on their abdomen.

Like other spiders, Hobo Spiders prefer to keep their distance from humans. They often hide in firewood, behind furniture, in closets, basements, cellars, and similar areas.

Hobo Spiders are more aggressive than most other spiders on this list, but they aren't aggressive overall. They're more likely to bite if you get close to them, but they won't bother you if you avoid potential hiding places.

If a Hobo Spider bites you, you might not notice right away. Hobo Spider venom kicks in overtime. The wound becomes a blister a day or so after the initial bite. Two or three days after the bite, the blister opens and drains. After a week, the person is left with a small open wound. This wound will heal over several months.

Other Spiders to Watch For

We've discussed the most dangerous spiders that are native to the US, but there are others worth mentioning. These spiders are less dangerous, or far less common, but things have happened.

Brazilian Wandering Spider

As the name implies, this spider is native to South America rather than North America. However, incidents have occurred in the US due to this spider's habit of hiding in banana clusters or leaves. This habit has given the spider and some of its relatives another name: the Banana Spider.

Their tendency to hide in bananas has also caused a few bites in the United States and elsewhere. Wandering Spiders are present throughout the northern half of South America, including places like Ecuador.

One of Ecuador's biggest trading partners is the US, and bananas are among its top exports. These spiders have hitched a ride in banana shipments, to supermarkets, and eventually into homes. Such incidents are isolated, though, so you shouldn't worry about them.

Yellow Sac Spider

Unlike the other spiders on this list, yellow sac spiders don't have lethal venom. They are venomous to some extent, though. Their bites can cause pain and itchiness. It'll also leave a nasty-looking cut behind.

Yellow sac spiders bite more people in the US than any other spider on this list. They're quite common and have a wide range. They're also comfortable both indoors and out, so they interact with humans more often. Another reason for the frequency of Yellow Sac Spider bites is that one of the two species is invasive, so it has no natural predators.

Spider Removal

If you do have poisonous spiders in your home, the next step is pest control. Getting rid of spiders is sometimes a matter of picking things up and avoiding clutter. This deprives spiders of places to hide, so they're less likely to stick around in your house.

Large infestations require help from a professional pest service. If you don't want exterminators coming in and spraying your house, you don't have to. We offer a DIY service where we ship the equipment and instructions to you.

Perfume Power?

There's an old myth that perfume kills spiders, but it's not completely true. Perfume can kill spiders, but it doesn't always. You can use it to deter spiders, but not for long.

Spiders hate the smell of citrus and other acidic products. Spiders have a keen sense of smell, so strong smells overwhelm them and make them dizzy. They'll also avoid these smells if they can.

Perfume is often expensive and doesn't last long. It'll do to scare off spiders you see and can work as an insect repellant in a pinch, but you're better off with actual pesticides.

Name That Spider

Suppose you still can't tell what type of spider you're dealing with and aren't sure what kind of services you need. That's not a problem. We'll help you identify the spider and send you the appropriate equipment. If you have other questions, you might find the answers on our FAQ page.

How to Tell if a Spider is Poisonous and Get Rid of It

If you own a home, knowing how to tell if a spider is poisonous is important. We've discussed how to do this here, but knowing when a spider is dangerous is one part of it. Getting spider treatment comes next.

If you need extermination services in your home, you can get a free quote on our site. Feel free to reach out to us at Remedy if you have other questions or concerns.

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