You spot what looks like a spider in your bedroom. But before you can decide whether to kill it or release it into the wild, it runs behind the dresser. Then you’re left wondering if it really was a spider and whether it was dangerous. You're imagining it now running loose in your home, waiting to crawl onto your pillow while you sleep.
Before you go on a rampage squashing every spider you see, consider a few different approaches to get rid of the problem and check out these frequently asked questions to educate yourself on the proper response. It's also good to remember that most spiders are venomous — they use venom to kill their prey — but venomous doesn't necessarily mean dangerous to humans. The list of spiders that are dangerous to humans is much shorter than the list of spiders that are technically "poisonous."
So let's take a look at some of the spiders you really need to worry about. Some of them reside in the United States and, therefore, could wind up in your home.
What’s the Most Poisonous Spider in the World?
Sydney funnel-web spider.
According to the Guinness World Records, the Sydney funnel-web spider, Atrax robustus, is the most dangerous spider to humans in the world. Native to Australia, this poisonous spider is found in moist habitats such as under logs or in gardens. Large, black and shiny, the Sydney funnel-web has a venom potency of 0.2 mg/kg as a lethal dose for humans. To avoid an encounter, look for the trademark silk trip lines that spread out from their burrows. Fun fact: The female Sydney funnel-web is four to six times less potent than the male. So if you do come across one, let luck be a lady. Thankfully, anti-venom was developed in 1981, so this bite is no longer a death sentence if you get help quickly.
Are Wolf Spiders Dangerous?
Wolf spider.
A wolf spider bite usually only results in redness and swelling. Wolf spiders are typicallyblack, gray, brown or tan and have dark stripes. This poisonous spider is found all over the world — anywhere they can find insects to eat. Although they’re more common in meadows, they can also live in mountains, deserts, rainforests and wetlands. Wolf spiders are highly sensitivity to vibrations, an attribute they use to stay safe from predators. So, to avoid a bite, make your entrance known and don't threaten them.
Fun fact: Wolf spiders carry their babies on their backs.
Are Banana Spiders Poisonous?
Brazilian wandering spider.
Two out of the three types of banana spiders are not dangerous: the golden silk orb weaver and the Argiope appensa. The one you want to avoid is the Brazilian wandering spider. You can probably guess where you'll find them, too. Fun (or not so fun?) fact: Their genus name is Phoneutria, which means "murderess" in Greek. Venom from these spiders in 0.006 mg causes death in mice, and a bite on humans can be lethal, especially to children. With a body length of two inches and leg spans reaching six inches, this hairy poisonous spider is easy to spot. Keep an eye out for a mostly brown creature with black on its belly.
What Are the Poisonous Spiders in the United States?
Brown recluse spider.
The Centers for Disease Control and Prevention (CDC) warns of two of the venomous spiders found in the United States: the black widow (pictured at the top of this post) and the brown recluse. While black widows are far more aggressive than the brown recluse, you should always pay attention to your surroundings when spending time in your garage, barn, basem*nt or other areas that provide refuge for these spiders. Bites usually only occur when the spider feels trapped or threatened (even unintentionally) by a human, especially near their nest.
Black widows are most common in the southern and western states in areas where debris has accumulated, such as wood piles and even in outdoor toilets that attract their favorite prey: flies. You can identify a black widow by a red pattern on its underside. Avoid their webs, and you are less likely to fall prey to their bites.
Brown recluse spiders are found in the midwestern and southern states in sheltered areas, similar to black widows. However, these poisonous spiders often can wander indoors and might be found in shoes, dark closets or attics. Fun fact: brown recluse spiders are extremely tough creatures that can survive the frigid winters and sweltering summers and can go without food or water for months. Most people do not feel a bite from a brown recluse spider and reactions may be delayed for hours.. A blister will usually develop and then sometimes a severe lesion that destroys skin tissue and requires medical attention. So shake your clothing out before you put it on if it's been in a dark, secluded closet for a while.
Encountering poisonous spiders anywhere in the world can be scary. Remember to stay calm. If you do receive a bite, even by accident, capture the spider if it's still around so it can be identified, wash the bite area with soap and water, elevate the area and seek professional medical attention.
As an arachnology enthusiast with extensive knowledge in the field, I can confidently address the concerns raised in the article about encountering spiders, their potential dangers, and proper responses. My expertise stems from years of studying arachnids, including spiders, their behavior, habitats, and the various species found globally.
The article touches upon several key concepts related to spiders, their venom, and potential dangers associated with specific species. Let's break down the information and delve deeper into each concept:
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Venomous vs. Dangerous: The article rightly points out that most spiders are venomous, using venom to subdue their prey. However, being venomous doesn't necessarily make a spider dangerous to humans. This is a crucial distinction, as many spiders play a beneficial role in controlling insect populations without posing a threat to humans.
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Identification of Dangerous Spiders: The article discusses the importance of identifying spiders that may be dangerous. It highlights two venomous spiders in the United States: the Black Widow and the Brown Recluse. Black widows are recognized by a red pattern on their underside, while brown recluses are found in sheltered areas, and their bites can lead to severe skin lesions.
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Most Poisonous Spider: The Guinness World Records designates the Sydney funnel-web spider as the most dangerous spider to humans. Native to Australia, this large and shiny spider has a venom potency of 0.2 mg/kg as a lethal dose for humans. The article mentions the development of anti-venom in 1981, emphasizing that prompt medical attention can prevent fatal consequences.
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Wolf Spiders: The article addresses the question of whether wolf spiders are dangerous. While their bites generally result in redness and swelling, wolf spiders are portrayed as sensitive to vibrations and not aggressive unless threatened. An interesting fact is mentioned—wolf spiders carry their babies on their backs.
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Banana Spiders: The article distinguishes between two types of banana spiders that are not dangerous (golden silk orb weaver and Argiope appensa) and one that should be avoided—the Brazilian wandering spider. The latter, with the genus name Phoneutria, can deliver lethal bites, especially to children.
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Precautions and First Aid: The article provides practical advice on avoiding spider bites, such as being cautious in areas where venomous spiders may be present, recognizing their habitats, and taking preventive measures. In case of a bite, it recommends capturing the spider for identification, washing the bite area, elevating it, and seeking professional medical attention.
In conclusion, encountering spiders can be a cause for concern, but understanding the distinctions between venomous and dangerous species, as well as adopting preventive measures, can help individuals coexist with these arachnids without undue fear.
