13 Most Dangerous Spiders in the World

Let’s face it:

Everyone is at least a little scared of spiders.

Just the sight of their long legs and sharp fangs is enough to send shivers down your spine.

But what if we told you that there are some spiders whose bite can cause a lot of pain and sometimes even kill a person?

Yes, you read that right. There are spiders around the world that can deliver venom that can lead to some very painful circumstances and even kill a person if they do not receive medical attention.

THE MOST DANGEROUS SPIDERS In The World
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But before we head into the list, let’s shed some more light on the topic before we head onto the list.

Should You Be Afraid of Venomous Spiders? Are All Spiders Dangerous?

We know that most people, especially those with Arachnophobia (the fear of spiders) would be completely freaking out right now. But let’s not jump to conclusions here.

Yes, it’s true that all spiders contain venom. This venom contains neurotoxins that are used by spiders to immobilize their prey long enough to catch them. Luckily, the venom of the majority of spiders is too weak to cause any damage to humans. To give you a rough example, out of more than 3,000 species of spiders in the United States, only 2 are capable of doing any actual damage to humans with their venom.

More than that, spiders don’t particularly consider humans as their prey. In fact, most spiders will try to hide or run away or sometimes even play dead if they encounter a human. They will only consider biting humans as a last resort and will do so in defense.

In addition to this, you should also know that spiders only have a limited amount of venom in their bodies. Even if one of the most dangerous spiders in the world bites you, they’ll only release enough venom to allow them to escape unharmed. This quantity, even from some of the most dangerous spiders, would be highly unlikely to cause death.

You can also take comfort from the fact that antivenin is now available for almost all of the dangerous species of spiders around the world. So, if you suspect that a dangerous spider has bitten you, you can visit a hospital where you’ll be administered with an antivenin. Since the development of antivenins, deaths from the bite of even the most dangerous spider in the world (Sydney Funnel-Web Spider) has come down to zero.

List of the Most Dangerous Spiders in the World

13. Mouse Spider

  • Genus: Missulena
  • Species: M. Bradleyi
  • Color: Dark Blue, Black
  • Size: 10mm – 35mm

Mouse spiders can be found mostly around all mainland areas in Australia. They have a distinct, bulging head and round jaws. The body of the mouse spider is usually black or dark blue and females are stockier than males.

Although mouse spiders are often confused with funnel-web spiders, their biting incidents are usually uncommon as these spiders don’t reside in urban areas that are heavily populated. This means you’re unlikely to find one casually wandering around your home.

The scary part is that even though mouse spider bites are typically uncommon, their venom is almost as toxic as that of the funnel-web spiders. If provoked, the mouse spider will bite resulting in fatal neurotoxic symptoms. Fortunately, mouse spider bites are rarely fatal and can also possibly be just a ‘dry bite’. Also, funnel-web spider antivenom can be used to treat the bite of a mouse spider as well.

12. Fringed Ornamental Tarantula Spider

  • Genus: Poecilotheria
  • Species: P. Ornata
  • Color: Greenish, Purplish, Brownish
  • Size: <10 inches

Fringed Ornamental Tarantula Spiders is a large arboreal tarantula species and is native to Sri Lanka. This species has a unique greenish and brownish hue and is very commonly kept as a house pet.

This species is known to be the most venomous out of all the tarantula species. These spiders can move very fast and will usually bite if they are cornered or mistake a finger as a threat while feeding.

And although initially, the bite may present itself simply as redness and swelling, with time it can cause myotoxic symptoms like muscle spasms and cramps. Other symptoms also include stiffness, joint pain, and tightness in the chest.

There have been reports of people going to the emergency room due to the severe muscle spasms and sweating which occurred just a few hours after a fringed tarantula bit them.

11. Wolf Spider

  • Super Family: Lycosidae
  • Family: Lycosidae
  • Color: Brownish and Grayish
  • Size: 1cm – 8cm

The Wolf spider is a member of the Lycosidae family. It has almost 125 species in North America and around 50 species in Europe. These spiders are typically small to medium-sized and can be anywhere around half an inch to two inches in length. They have a hairy body in a brownish grayish shade and they have long legs and bodies. Wolf spiders get their name from their hunting behavior such as pouncing on its prey which resembles that of a wolf.

Fortunately, wolf spiders are pretty non-aggressive and will not bite unless provoked. But even if they do bite you, there’s nothing to worry about as their venom is non-lethal. Some people also compare the bite to that of a bee sting. Usually, a wolf spider’s bite will only cause inflammation and swelling on the bite area and itching for some people.

If you do get bit by a wolf spider, wash the bite area with warm water and soap. Apply an ice pack to reduce swelling and pain. You can also treat the bite with an over-the-counter medicine that reduces itching and swelling.

10. Yellow Sac Spider

  • Family: Eutichuridae
  • Genus: Cheiracanthium
  • Color: Pale, Yellowish, Beige
  • Size: 5mm – 10mm

The Yellow sac spider belongs to the Clubionidae family and is around half an inch long and pale in color. These spiders around found throughout the world including several parts of the United States, South America, Australia, Europe, and Japan. The habitat of these spiders is silken tubes which they build under leaves, logs, tree barks and stones. Inside homes, these spiders will typically build their silken sac along with ceilings and behind furniture as well.

A bite from a yellow sac spider will cause a red weal with a necrotic center. Because their venom contains cytotoxins, the bite may create a lesion in some severe cases. If this is the case, you should take care of that lesion and keep it clean to avoid any chance of infecting the wound. Other than that, there are no serious symptoms resulting from a yellow sac spider’s bite. The worst that can happen is the venom can cause headaches, dizziness, and fever in some victims.

9. Red Widow Spider

  • Genus: Latrodectus
  • Species: L. Bishopi
  • Color: Redish Orange, Black abdomen
  • Size: 1.5 – 2 inches

The red widow spider or the red-legged widow spider belongs to the Latrodectus genus and is a close relative of the black and brown widow spiders. These spiders are mostly found around southern and central Florida and usually live in sand dunes. It has reddish legs and a brownish blackish abdomen with red or orange spots. Female red widow spiders are usually 1.5 – 2 inches and males are about one-third of the size of that.

Just like other spiders of the Latrodectus genus, the red widow also contains a neurotoxic venom that can lead to painful symptoms. These include sweating, extreme pain, rapid heartbeat, and muscle cramps to name a few. Although most of the symptoms are quite painful, they’re rarely fatal. Although, children, elderly and people with medical issues might be at a higher risk of fatality from the bite of a red widow.

Luckily, these spiders are not very aggressive and only bite if threatened. They’re more likely to bite if trapped under clothing or when they’re protecting their eggs.

8. Chilean Recluse Spider

  • Genus: Loxosceles
  • Species: L. laeta
  • Color: Light Tan, Brown
  • Size: 0.3 – 1.6 inches

The Chilean Recluse Spider is a native South American species that is said to be the most dangerous of the Recluse species. The spider ranges from 0.3 – 1.6 inches in size and has a light tan or brown color with a marking on the upper side of the thorax. These spiders are usually common in Chile, Uruguay, Argentina, Peru, and Brazil. However, they’ve been introduced to parts of the United States such as Los Angeles, Canada, Australia, and even Finland through fruit shipments.

Thankfully, these spiders have a calm temperament and do not bite unless startled or frightened. They might also bite if pressed against clothes. If these spiders do bite, they release their venom which contains a dermonecrotic agent which can lead to mild to severe skin necrosis. Their bite might take some hours before symptoms begin to show up. Blisters caused by such a bite may take weeks or even several years to heal and will leave deep scars on the skin.

Because the venom of this spider is most potent at higher temperatures, the ice pack must be immediately applied at the bite spot to slow down the effects. Aloe Vera can also be used to soothe the pain. Although the Chilean Recluse spider bite has been known to cause severe systemic reactions, it has been cited to cause death in 3 – 4% of the cases as per the CDC.

7. Redback Spider

  • Genus: Latrodectus
  • Species: L. hasseltii
  • Color: Black, Black abdomen with Red marking
  • Size: 1 cm (females), 3 – 4mm (males)

Redback spiders or otherwise known as Australian black widow are yet another close relative of the black widow spider and part of the Latrodectus family. These spiders are easily recognizable by their black body with a prominent red line running across the abdomen. Usually, the females are about 10mm in size while males are much smaller, around 3 – 4 mm on average. This species is native to Australia and originates from the Southern and Western parts of the country, but they can be found throughout the continent now. These spiders have now also spread to other countries as well such as New Zealand, Japan, and Belgium through the export of grapes.

le males are much smaller, around 3 – 4 mm on average. This species is native to Australia and originates from the Southern and Western parts of the country, but they can be found throughout the continent now. These spiders have now also spread to other countries as well such as New Zealand, Japan, and Belgium through the export of grapes.

This species tends to prefer warm environments and often finds shelter in urban areas or human residences. Redbacks are not a very aggressive species and usually play dead if threatened. Also, only 10 – 20% of redback bites are venomous. However, if a redback is trapped against your skin under clothing or you threaten a female protecting her eggs, they’ll very likely bite you. Their neurotoxic venom produces symptoms like pain, sweating, rapid pulse rate, nausea and vomiting within hours of the bite. The pain usually starts from the bite site and travels up to the entire limb and normally persists for around 24 hours. In Australia, around 250 redback bites are treated annually using antivenin that was invented in 1956. The last reported death from a redback bite was also in 1956. Thanks to the antivenin, death from a redback’s bite is a very rare occurrence these days, however, some symptoms are known to remain despite treatment.

6. Black Widow Spider

  • Genus: Latrodectus
  • Color: Black, Red markings on Abdomen
  • Size: 1.5 inches

The Black Widow is perhaps the most well-known species of the Latrodectus genus and is considered as the most venomous spider in North America. Black Widows have a shiny, black body and a unique red hourglass-shaped mark on the bottom of their abdomen. Female black widows are almost 1.5 inches long and males about half the size of that, although male black widows are a very rare sight. This species gets its name from their mating ritual where the female spider kills and consumes the male spider, hence the name Black Widow. These spiders are most common in the temperate regions such as the United States, Canada, Australia, West Indies, Southern Europe, and Asia, Australia and most of South America. Black Widows usually inhibit dark and dry areas of homes such as garages, basements and hollow stumps.

A bite from a black widow isn’t more painful than a pinprick at first, but it only escalates from thereon. Within a few minutes, the pain will start spreading to the rest of the body. Symptoms like partial paralysis of the diaphragm leading to difficulty in breathing, severe muscle cramps and pain, sweating, chills, nausea, and headache usually follow. Symptoms may last for 8 to 12 hours unless an antivenin is administered. Black widows are known to have the strongest venom of their genus, which is 15 times stronger than that of a rattlesnake. But still, the chances of a fatality are less than one percent, and it’s a fairly rare occurrence. Do note that the elderly and children are still at a higher risk of fatality from a black widow’s bite than an adult. Black widows also non-aggressive and only bite in case they’re threatened or trapped against a person’s skin.

5. Brown Widow Spider

  • Genus: Latrodectus
  • Species: L. Geometricus
  • Color: Light Tan, Dark Brownish, Grayish
  • Size: 0.5 inches

The last of the Latrodectus genus on our list and perhaps the most lethal too is the Brown Widow spider. This species has though to have originated from South Africa and South America, both where the first specimens were first discovered. Brown widows can now be found throughout the world including the United States (especially Southern California), South Africa, Australia, Japan, Madagascar, Cyprus, and Southern Europe. These species have a dark brown to tan to even black color and range from 1 – 1.5 inches in size. They also have a distinct hourglass-shaped mark on their abdomen which is of a yellowish or orangish color, just like the rest of the members of the Latrodectus genus. The brown widow makes its home inside vegetation or shrubs, old automobiles and tires, and other quiet places.

The reason why brown widows are the most lethal is that their venom is almost twice as strong as that of black widows. It also contains the same neurotoxins which can trigger extremely painful muscle spasms and cramps that can last up to several hours. But mostly, the venom is released in very minuscule quantities which normally causes swelling and reddening of the bite spot at its best. Also, these spiders release much lesser venom and are shyer than black widows and only bite when in danger.  

4. Brown Recluse Spider

  • Genus: Loxosceles
  • Species: L. Reculsa
  • Color: Light Tan, Brownish
  • Size: 6 – 20mm

The brown recluse spider is considered as one of the three most dangerous spiders in the United States. This species of spider is usually found in the Southern and Central parts of the United States. The color of these spiders is usually light or dark brown or sometimes even a darker shade such as blackish gray. They have a distinct marking on the dorsal side of their thorax that resembles a violin. On average, the size of a brown recluse is somewhere between 6-20 mm, while some maybe even larger. These spiders usually inhabit dark and quiet places that don’t receive too much disturbance such as basements, closets, garages, and woodpiles. 
 
The reason why brown recluse spiders are dangerous is that they contain a very powerful hemotoxic venom. Although at first, the bite may be painless, with time the enzymes in the venom start to eat away the local cell membrane which leads to the breaking down of skin and blood vessels. This leads to necrosis and the formation of very painful lesions on the bite site. Other symptoms that victims notice includes pain and redness at the bite site, nausea, joint pain, fever, and severe itching. However, brown recluse spider bites are rarely fatal as they inject a very small amount of venom, despite the fact that it’s stronger than that of a rattlesnake. Also, there are over 20,000 species of brown recluse spiders and only 60 of them are capable of biting humans. And even if they belong to that species, these spiders are usually non-aggressive and only bite if they feel vulnerable or are pressed against the skin. If in case a brown recluse spider does bite you, you should apply an ice pack on the site of the bite and seek medical attention for correct diagnosis. Deaths from brown recluse spider bites have only been recorded in young children and the elderly.  

3. Six-Eyed Sand Spider

  • Family: Sicariidae
  • Genus: Hexophthalma
  • Color: Light Tan, Light Brownish
  • Size: 0.3 – 0.6 inches

The Six-eyed sand spider is a close cousin of the recluse spiders and is considered as one of the most dangerous spiders in the world. These spiders are a native South African desert species and are usually found in very remote locations, because of which there are very few reported cases of bites from this spider. It’s covered in small hairs called setae that hold sand particles and allows them to camouflage while they bury themselves below the sand and wait to ambush their prey. These spiders are 0.3 – 0.6 inches long on average and have a light tan or light brownish color.

Although there are probably just two reported incidents of this spider biting humans, its venom has proved to be lethal to humans. The venom has a very strong necrotic or hemolytic effect on humans and once it enters the body, it starts destroying the tissue, causes the leakage of blood vessels and bursts the red blood cells leading to hemorrhaging and organ death. Also, there is currently no antivenin for this spider so a bite will very likely be fatal for any human being. From the two reported cases, one has caused amputation and the other was believed to cause death from hemorrhaging.

2. Brazilian Wandering Spider

  • Family: Ctenidae
  • Genus: Phoneutria
  • Color: Brownish, Blackish
  • Size: 2 – 6 inches

The Brazilian Wandering Spider is still regarded by many as the most dangerous spider in the world. Its lethal venom has reportedly caused 10 deaths as of yet and is capable of producing extremely painful symptoms. Otherwise known as banana spiders, almost all of the Brazilian Wandering Spider species can be found in Brazil and throughout Latin American countries such as Costa Rica and Argentina. Often times, these spiders spread to other countries through shipments of bananas and have been reportedly infested homes in the United Kingdom. On average, the body of these spiders can reach up to 2 inches, while their legs can grow up to 6 inches. Their body has a hairy texture and usually has a brownish blackish shade to it with black spots on their belly.

One of the reasons why these spiders tend to be so dangerous is because they have an aggressive nature. Instead of building webs, these spiders wander on forest floors at night during which they actively hunt their prey, often ambushing them. So, it’s a possibility that these spiders can creep into your house while on the lookout for predators. However, these spiders are not aggressive toward humans. But if they feel threatened or are startled, they exhibit a defensive behavior in which they raise their two front legs which means they are alert and ready to attack.

The neurotoxic venom of the Brazilian Wandering spider is regarded as the most destructive neurological venom of all spiders in the world. Initially, the spider’s bite will cause an intense burning sensation at the bite spot, followed by sweating and goosebumps. But within around 30 minutes, the venom starts messing with the nervous system resulting in either high or low blood pressure and increased or decreased pulse rate, nausea, fever, abdominal cramping, and blurred vision. In addition to this, male bite victims have also reported suffering from priapism which can become a cause of impotence. Despite this, it’s quite rare that a spider injects all of its venom or simply enough to kill you. Still, it’s recommended to immediately seek medical attention if you’ve been bitten by a Brazilian Wandering spider as a precautionary method and to save yourself from the cringy symptoms.

1. Male Sydney Funnel-Web Spider

  • Genus: Atrax
  • Species: A. Robustus
  • Color: Dark Brownish, Dark Bluish, Blackish
  • Size: 1 – 5 cm

The Sydney Funnel-Web Spider is the most dangerous spider in the world as per Guinness World Records and is truly a spider you would never want to encounter in your life. These spiders get their name from their web-building behavior in which they build a horizontal web with a funnel in the center. They wait for prey to land on the web and they jump out of the funnel and drag them in. Their body is shiny and usually of a dark brownish or blackish shade. These spiders can grow up to 2 inches but some can be even bigger than that. Although there are many species of funnel-web spiders, the Sydney funnel-webs’ which can be found in a 100 km radius of Sydney, are the most dangerous ones.

The venom of the Sydney funnel-web spider contains a lethal compound called an atracotoxin which is extremely dangerous for humans and other primates but surprisingly doesn’t has such severe effects on other mammals. Also, for the case of Sydney funnel-web spiders, the venom of the males tends to be more toxic than the females, which as five to six times less dangerous. If you see this spider, it’s generally recommended to avoid getting too close as they can become very aggressive. If you do encounter one, they’ll likely charge towards you and bite you with their long and sharp fangs that are capable of puncturing fingernails. These spiders will deliver a full envenomation and will try to repeatedly bite you.

Because of the high pH of the fangs, the site of the bite will become inflamed and will cause extreme pain. Following this, the muscles around the mouth go numb and the victims often start salivating excessively. Within 30 minutes, the person will start having difficulty breathing and will become disoriented, which often leads to unconsciousness. If someone’s been bitten by a Sydney funnel-web spider, it’s crucial that they receive immediate medical attention so they can be given the antivenin. Before the development of the antivenin in 1981, this spider has accounted for 13 deaths in total. One included a child who was bitten on the chest who died in just 15 minutes. Fortunately, no one has died ever since the antivenin was made so it’s important that the victim reaches the hospital after getting a bit as soon as they can.

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