10 Most Venomous Spiders in the World

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Spiders evolved over 380 million years ago, and are a vital part of the world’s ecosystem. However, just because they’re old and important doesn’t mean some of them aren’t absolutely terrifying. Yes, many of them are harmless, but others we would rather stay away from because they’re incredibly venomous. The good news is that deaths from spider bites are very rare and they only do it if they feel threatened. So even though some spiders can kill you, they would rather not.

10. Yellow Sac Spiders

Yellow Sac Spiders are part of the Cheiracanthium genus, and there are different species found throughout the world, like the United States, Australia, Europe, and Japan. Both males and females are about half an inch big and are often pale in color. One interesting thing to note about Yellow Sac Spiders is that they love the smell of gasoline. This problem actually led Mazda to recall 52,000 cars in March 2011 because Yellow Sac Spiders were building webs in the emissions system.

Besides just being annoying to car manufacturers, Yellow Sac Spiders are also venomous. The immediate bite of the spider is incredibly painful and can lead to redness and swelling. Luckily, unless someone has an allergy to the venom, there are rarely any lasting effects.

9. False Widow Spider

False Widow Spiders are believed to have first come to England in shipments of fruit in the 1870s. They are often cited as the most venomous spider in England and currently their population is expanding due to climate change. The symptoms of a bite are often quite different. However, the bitten area can swell up to the size of a tennis ball.

Professional soccer player James Gray was bitten by a False Widow Spider on his right arm in March 2016. He said at first he didn’t think much of the bite, it just developed into a red spot. He said that he felt run down, but didn’t think that it was the spider bite that caused it and attributed his fatigue to his training. He only found out about the bite when he went to see the team’s doctor a few days after the bite. By then the infection had spread and he was hospitalized. He had surgery and they cut the infection out, leaving a hole in his arm. He was ultimately sidelined for a month because of the spider bite.

There is only one death related to a False Widow Spider. In 2014, Pat Gough-Irwin died a month after being bitten by a False Widow Spider. However, it was never proved conclusively and spider experts say that there is nothing in the venom of a False Widow Spider that could kill a person.

8. Brown Recluse Spider

You’ll know when you see a Brown Recluse Spider because of a violin shaped marking on the top of their cephalothorax, which is a fused head and thorax. This is why Brown Recluse Spiders are sometimes called fiddleback or violin spiders. But what really sets them apart is that they only have six eyes instead of eight like most spiders.

Brown Recluse Spiders are only found in central and southeastern United States and they are fairly small, about the size of a penny. However, for being a small spider they can pack a powerful bite. Luckily, 90 percent of bites don’t require medical attention and usually don’t scar.

For the other 10 percent who are sensitive to the spider’s venom, well, it definitely isn’t a fun experience. First, a white blister will grow around the bite and the tissue may become hard. The area of the bite can develop blue-gray or blue-white patches that have ragged edges and are surrounded by redness.

Even more frightening is that a bite can develop into a volcano lesion. This happens when the tissue around the bite becomes gangrenous and this results in a nasty open wound. As for how big these wounds get, they can be as big as a human hand. Usually, it takes eight weeks to heal, which is a long time to recover from anything, but it sounds like a lifetime to have a gaping, gangrenous wound on your body.

Luckily, fatal Brown Recluse Spider bites are incredibly rare. There were only two recorded deaths between 2004 and 2014.

6. The Redback Spider

The Redback Spider is a close relative to Black Widow Spiders (you’ll notice the striking resemblance), but the Redback is only found in Australia and they are recognizable because they have a red stripe on their back. The red is much darker on females than on the males. They are a medium sized spider, and their bodies are about the size of a large pea.

Luckily, most Redback Spider bites aren’t serious. Only about 250 bites every year need antivenom. A person usually experiences sweating (especially near the bite), nausea, muscle weakness and vomiting. We’re pretty sure that these symptoms would have been extremely uncomfortable for the man whose penis was bitten by a Redback spider in April 2016 while he was using a public toilet. Luckily, he was released from the hospital after a few hours of sheer panic and terror.

Since the introduction of the antivenom in 1956, there has been one possible death caused by a Redback spider bite, which would make it the first death from any spider in Australia since 1979. In April 2016, 22-year-old Jayden Burleigh was bitten by a Redback spider under his left arm. He was hospitalized for four days and given antibiotics. He died three days after being released from the hospital, so it’s unclear if his death was caused by the bite or some other factor.

5. Brazilian Wandering Spider

There are eight different types of Brazilian Wandering Spiders, and as you may have guessed, they are predominantly found in Brazil, with a few species spread out across Latin America. They are about two inches long with a leg span of about six inches.

Brazilian Wandering Spiders differ from other spiders because they don’t lure prey into a web. Instead, they spend most of their day in cool areas. Then at night, they hunt on the floors of the forests. They either wait to ambush their prey or directly attack them; making them some of the most aggressive spiders in the world.

However, they are not aggressive towards humans. Actually, none of the spiders on the list are. Most of the time spiders bite humans because they feel trapped and/or cornered. That being said, you definitely do not want to frighten a Brazilian Wandering Spider.

After a bite, the person may experience a burning sensation in the area of the bite, along with goosebumps and sweats. About 30 minutes later, the person’s blood pressure may increase or decrease and their heartbeat may go faster or slow down. Nausea, abdominal cramping, blurred vision, hypothermia, vertigo, and excessive sweating are also symptoms of a bite from a Brazilian Wandering Spider. Another unusual side effect is that in males, is that it can cause a painful erection that could last several hours. Needless to say, when a Brazilian Wandering Spider was found in a bag of bananas purchased by a family in Leicester, England, the tabloids had a field day writing horror stories about the terrifying venomous spider that causes erections.

The good news is that in most cases, the Brazilian Wandering Spider doesn’t secrete enough venom in a bite to cause serious damage. A study from 2008 found that from all bites, only 2.6 percent needed antivenom. However, it is still important to seek medical attention after a bite because 10 recorded deaths have been contributed to the spider.

4. The Black Widow Spider

One of the most notorious spiders is the Black Widow Spider. They are found in regions that are temperate, dark, and dry throughout much of the world, including the United States, South America, Africa, southern Europe and Asia, and Australia.

The females are the most distinctive of the species for several reasons. The first is that they are about twice the size of males, and they are about 1.5 inches long. They have an hourglass shaped body that is shiny. Also, on the underside on the right abdomen, there is a distinctive red hourglass marking. They get their unique name because after mating, the female eats the male.

Most of the time people who are bitten by Black Widow Spiders don’t suffer any serious symptoms. However, according to National Geographic, their venom is 15 times stronger than a rattlesnake, so if they bite and inject a lot of venom, then the person could be in a lot of trouble.

At first, the person will feel a sharp pain at the area of the bite, like a pinprick. The bite area will redden and swell. Then, as early as 15 minutes after the bite, pain will spread throughout the body, especially in the chest and abdomen. The muscles in those areas will start to cramp because of severe spasms. This may lead to difficulty breathing because the diaphragm can become paralyzed.

Black Widow Spiders are rarely deadly to healthy adults, there is less than a one percent chance of a bite being fatal, but they can be dangerous to children, the elderly, and sick people.

3. The Brown Widow Spider                                             

As you’ve probably already guessed by its name, the Brown Widow Spider is a close relative of the Black Widow Spider. The Brown Widow Spider is different in color, ranging from gray to dark brown, whereas Black Widows are brown to black. They also have an hourglass marking on their abdomen. They are about 1 inch to 1.5 inches long and are usually found in tropical areas. However, since 2003, their population has been exploding in Southern California. They hide in places that don’t see much human traffic or undisturbed areas like piles of brush or wood.

The venom of the Brown Widow Spider is actually more toxic than the Black Widow Spider, but luckily the Brown Widow doesn’t inject as much venom and they are much shyer and less aggressive than Black Widows, so there is less of a chance of being bitten by one. However, when they do bite, they hurt. One man who was bitten in the neck said that the pain was so bad after 10 minutes that it felt like he was hit with a sledgehammer. The symptoms start with redness and swelling. This is followed by cramps and spasms that can last for several hours. Luckily, there are no recorded deaths from Brown Widow Spiders.

2. The Sydney Funnel-Web Spider

There are 43 different kinds of Funnel-Web Spiders and they are all found in Australia. The funnel web spiders get their names because of the distinctive style in which they build their webs. They find wet ground and then build a horizontal web with a funnel in the center of it that often leads into the ground or some other type of shelter. The spider waits in the funnel until prey lands on it and then springs out, and drags the prey down. What sets the Funnel-Web Spider apart from other spiders that build horizontal webs is that it uses irregular strings of web to set up “tripwires” near the entrance of the web. This gives the spider an advanced warning that prey is nearby.

One of the most dangerous of the Funnel-Web Spiders is the Sydney Funnel-Web Spider, specifically the males. They are generally found within a 62 mile radius of Sydney and are medium sized. Usually, the largest are 0.4 to 2 inches long. However, one at the Australian Reptile Park (which is used to milk venom for antivenom) is called Big Boy, and is a whopping four inches long. What makes Big Boy so terrifying is that the bigger the spider, the more venom they produce, and Sydney Funnel-Web Spider venom is some of the most dangerous in the world. In fact, if it were to bite you in your chest, it could kill you in 15 minutes. However, most of the time people are bitten on their limbs.

The male’s venom contains a polypeptide called Robustoxin which affects the nervous system of humans and primates, but doesn’t really affect other mammals. What happens when you first get bit is that it will be extremely painful because the Sydney Funnel-Wed Spider has long fangs and the venom has a high pH level. After the bite, the person may start drooling because they have numbness around the mouth and excess saliva. They may also have a copious amount of tears. Soon they will have problems breathing and may lose consciousness.

The good news is that there is an antivenom, which was developed in 1981, and no one has died since its discovery. Before that, it was responsible for 13 recorded deaths.

1. Six-eyed Sand Spider

The Six-eyed Sand Spider is a relative of the Recluse Spider and it is only found in the deserts of southern Africa. They are medium size spiders, they are about 0.3 inches to about 0.6 inches long, and they are covered in little hairs called setae. These hairs pick up particles of sand and it makes a camouflage for them. In addition to covering themselves in sand, the Six-eyed Sand Spider also hides by burying itself in the sand. When its prey gets too close, the spider ambushes it.

No one is exactly sure what happens when a Six-eyed Sand Spider bites someone. There are only two suspected cases of envenomation, but they couldn’t be confirmed. However, studies in labs have shown that the venom is quite dangerous because of a toxin called cryotoxin. Once it enters the body, it starts to destroy tissue and organs. So it ends up acting like sulfuric acid and eats away at the flesh, creating a lesion. Shortly after being bitten, hemorrhaging will start and the toxin spreads to the kidneys and liver, leading to death. Currently, there is no antivenom. Fortunately, Six-eyed Sand Spiders are notoriously shy. Perhaps we should keep our distance from them, unless you want to become evidence of what damage a bite could do to humans.

Robert Grimminck is a Canadian freelance writer. You can friend him on Facebook, follow him on Twitter, follow him on Pinterest or visit his website, or his true crime YouTube channel.


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1 Comment

  1. No. Just no. This is one of the worst researched lists I’ve ever seen.

    First and foremost, any list that doesn’t put the Brazilian Wandering Spider and Sydney Funnelweb in #1 and #2 (depending on who you talk to, these can alternate) isn’t worth the pixels it takes to print it.

    Second, in general, there isn’t an accurate top 10 list because not a lot of study on the LD50 of spiders has been done. However, typically, a more general list of dangerous critters goes like this:

    1 or 2. Brazilian Wandering Spiders

    1 or 2. Pretty much most of the Hexathelidae (funnel-web) family, especially the Atracinae and Macrothelinae subfamilies, especially Atrax (genus that contains A. Robustus, the Sydney Funnelweb).

    3. Widow spiders. In the US, this is typically one of the black widows or red widows. In Europe, the Mediterranean black widow is queen. In Africa, these are the button spiders. In Australian and Oceania, this is the redback or katipo. There’s also a brown widow that has worldwide distribution.

    4. Recluse spiders. The brown recluse is the most famous (and most often falsely attributed for spider bites where I live). There is one variant (the Chilean recluse) that may be more dangerous than the rest, but there is little data.

    Everything else is either non-deadly or has too little study to be usable. False widows, sac spiders, six-eyed spiders, hobo spiders, etc. In fact, of the ones above, the only ones that are even reliably deadly are the first two. The others are really only dangerous to children.

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