10 Most Dangerous Spiders in the World

5. Six-eyed Sand Spider (Sicarius hahni)

Six-eyed sand spider

Six eyed sand spider (Sicarius) Photo: Beliar spider / License

What’s got eight legs, six eyes and lives in the deserts of Southern Africa?! That’s right, the six-eyed sand spider.

The scientific name for this spider’s family is Sicarius which means ‘murderer’ and the spider is certainly an assassin. It hunts by burying itself in the sand and waiting for its unsuspecting victim to wander by at which point it pounces. In trials it was shown that the venom from a bite was fatal to rabbits in as little as 5 hours.

Like their close relatives, the recluse spiders, the venom of the six-eyed sand spider is a powerful cytotoxin. In the case of Sicarius the venom is both hemolytic and necrotic meaning it causes blood vessels to leak and destruction of  flesh.

But how dangerous is this spider to humans? Well we aren’t quite sure; there have only ever been two suspected cases of bites to humans and neither were conclusively attributed to the six-eye. Combined with the fact it can survive for a year on one meal it probably isn’t the biggest threat to humans.

4. Redback / Black Widow Spider (Latrodectus)

Redback Spider

Photo: © Laurence Grayson

The black widow spider, or redback as it is known in Australia is one of the most iconic spiders on the planet. Instantly recognisable by its round black abdomen with striking red markings these are definitely spiders not to be trifled with. Both the redback and the black widow are from the Latrodectus family with the redback being marginally more venomous than the black widow. And that venom is potent, more so than any other spider but one. The only reason these spiders don’t top the list is because they are smaller and deliver less of it.

The effects of this lethal toxin range from burning pain to a systemic condition known as latrodectism. Symptoms include general pain and swelling spreading from the affected area, abdominal cramps, nausea and sweating to name a few. This condition occurs in around half of bites and was often fatal in the very old and young before anti venom became available.

3. Brown Recluse / Chilean Recluse (Loxosceles)

Brown Recluse - Loxosceles

© Steve Collender

The recluse spiders occur in warmer climes throughout the world. Also known as violin spiders, fiddle-backs or even reapers these six-eyed spiders all possess tissue destroying venom and belong to the Loxosceles family.

Recluse spiders have garnered quite a reputation for themselves over recent years and the internet is awash with some pretty ugly photos of the effects of their bite. The venom of this group of spiders is known to be necrotic, i.e. flesh-eating and whilst usually mild, can result in a condition known as Loxoscelism. In these severe cases the area around the bite begins to die and a deep open sore is formed. There is no effective treatment for these bite wounds and they may take months to heal, sometimes requiring skin grafts.
In the very worse cases limbs have needed to be amputated and there have been a significant number of fatal bites, particularly from the Chilean recluse.

On a more positive note, the recluse is so called as it is relatively shy and not regarded as aggressive. Their small fangs also make it less likely they will deliver a significant dose of venom.
However, think twice before spraying them with a dose of bug-killer; it is reported that they are immune to some insecticides and only make them more toxic and angry!

2. Sydney funnel web (Atrax robustus)

Sydney funnel-web spider

Sydney funnel-web spider

The Sydney funnel-web spider (Atrax robustus)  is a veritable bruiser amongst the spider world. Whilst most spiders seek to avoid confrontation with humans the funnel-web will charge in delivering a volley of bites whilst clinging to its victim. So although its venom is no more potent than many of the spiders on this list, the funnel-web makes sure the unfortunate recipient gets the full dose.

In addition to its temperament the Sydney funnel-web is well equipped for the job. It has the most impressive fangs of any spider; these needle sharp weapons are longer than those of some snakes. Armed with these killer fangs and powerfully built, the funnel web is reputed to be able to bite through shoe leather and even finger nails.

Unlike virtually every other group of spiders it is the male Sydney funnel-web that is equipped with the most potent venom – up to six times stronger than that of the female. The venom itself is a neurotoxin which appears to be particularly effective against primates. Within minutes of being bitten the victim may suffer extreme symptoms such as muscle spasms, palpitations, vomiting, confusion and swelling of the brain. In some cases death has followed in as little as 15 minutes after the bite occurred.

The good news is an effective anti-venom was introduced in 1981 and there hasn’t been a death since.

1. Brazilian Wandering Spider (Phoneutria)

Brazilian wandering spider

Brazilian wandering spider (Phoneutria sp.) Photo: Geoff Gallice / License

When a spider’s scientific name is derived from the Greek for murderess (Phoneutria) you can guess it’s going to be trouble and this is certainly the case for the wandering spiders. According to Guinness World Records the Brazilian wandering spider (Phoneutria fera) is officially the world’s most venomous spider. It is capable of injecting a powerful neurotoxin which is nearly 20 times more deadly that that of the Black Widow spider if it gets into the blood stream. That is as potent as the venom of many deadly snake species and the effects are similar. The symptoms of envenomation include a loss of muscle control leading to breathing problems which can result in complete respiratory paralysis and eventually asphyxiation.
But there are two other major side effects to the wandering spider’s bite; firstly there is intense pain and secondly, if you happen to be male there is the four hour hard on. Yes, you did read that correctly – the bite of the Brazilian wandering spider can cause an erection that lasts for several hours, unfortunately it is also painful.

In addition to the this deadly venom the behaviour of the wandering spider make it particularly dangerous to humans. As its name suggests the spiders are not confined to a web in a dark corner. In fact they like to turn up in all manner of hiding places; boots, piles of clothes, log piles, cars and bunches of bananas. Also known as ‘banana spiders’ wandering spiders have been known to hitch a ride across the globe in boxes of bananas. In one case a man in the UK was bitten after buying bananas in his local supermarket.

There is little doubt that these are dangerous spiders. Their aggressive nature and close contact with humans have resulted in a number of deaths over the years. In one tragic case a single spider was responsible for the deaths of two children in São Paulo. Fortunately an effective antivenom has been developed and there have been relatively few fatalities since.

  • Bellarachnid

    The tarantula pictured in #7 is a Heteroscodra maculata not a Poecilotheria ornata (Fringed ornamental).

    • surfgatinho

      Well spotted! I couldn’t find a photo of Poecilotheria that I could use and thought I’d get away with it….

      • Gordon Hamilton

        Also Camel Spider and P.Ornata are not true spiders … and isnt P.Regalis more venomous ???

        • surfgatinho

          The article does say the camel spider isn’t a true spider. Poecilotheria on the other hand are definitely spiders.

          Not sure whether P. regalis is more venomous. From what I can gather both have “medically significant” bites, with the P. ornata being bigger and more aggressive.

          • Gordon Hamilton

            Tarantulas are not true spiders, ie: Pokies or Poecilotheria, P.Ornata are Tarantulas. I always understood it to be P.Regalis has the most potent bite, but maybe i am biased as i have 12 of them.
            http://www.livescience.com/41795-tarantula-bites-harmful.html

          • surfgatinho

            You may well be right about which is most venomous, but tarantulas are definitely spiders. Check out Wikipedia for starters:
            “Tarantulas comprise a group of large and often hairy arachnids belonging to the Theraphosidae family of spiders”.

            They differ from many other species of spider in that they are mygalomorphs meaning their fangs point down as opposed to operating like pincers, but they are definitely spiders…

          • Gordon Hamilton

            Sorry but they are Not, true spiders… They date from the time of the Dinosaurs, they can live up to 30 years, and have a number of differences from their more modern counterpart. I have been breeding them for 20+ years, but don’t take my word for it… There is plenty of information on Genus of Species

            QUOTE “” A tarantula is a large spider in the infraorder Mygalomorphae. (In fact, the French word for tarantula is mygale).
            The mygalomorphs differ from the araneomorphs, the so-called “true”
            spiders, in a number of ways. Chiefly, their fangs point down, whereas
            the fangs of true spiders join in a pincer-like arrangement. Some
            mygalomorphs are small or even tiny, but you’d never apply the word
            “tarantula” to one that wasn’t big and robust. “”

            This is from The British Tarantula Society, we site (pardon the pun)
            Very informative and worth reading…
            http://thebts.co.uk/forums/showthread.php?3908-Difference-between-spiders-and-tarantulas

          • Jokes

            Arguing on the internet is like the special Olympics. Even if you win, you’re still retarded.

          • Faber

            As far as I know (I am a biologist) the orders in which arachinds are divided are: “spiders”, “scorpions”, solifugae (camel spiders), amblypigids, uropygids, pseudoscorpions, acari (mitest and ticks) and maybe others. The scientific community puts tarantulas in the same order as spiders, so they ARE spiders, while ticks and scorpions and camel spiders are not. After all, taxonomy is just an agreement between scientists, since taxa (except fo the species) are man made categories and there would be hundred thousands of different ways to classify living beings according to their morphology, gene homology etc. (some more close their actual phylogenetical relationships, some less…), so it is quite pointless to discuss too much about taxonomy. Even if tarantulas are morphologically different from other spiders (the fangs etc.), they must be so genetically close to them that it is possible to assume that they both originated from a common ancestor, forming a so-called monophyletic group (all the descendents from a common ancestor). Anyway, as I said, taxonomy is man made, just accept what the scientific community has agreed, there is no reason to argue about something that is not real U.U

          • Grant Bogner

            Correct. Tarantulas are not “true spiders,” but they are still spiders. True spiders are a branch of spiders.

  • ColonelChair

    While the picture of the mouse spider you have is correct to some extent, I believe you might mean this one: http://australianmuseum.net.au/uploads/images/1918/dang_20_big.jpg

    • BrooklynsFinest718

      I believe that one is a female Mouse Spider which is twice as big and has more venom of-course, while the males are red-headed. But I also read that some females are red-headed too and bit bigger than the males. The venom from both has the same effects.

      • sparksflyswifty

        most males in spider species are smaller than the females. It is not an uncommon thing!

    • sparksflyswifty

      There are several sub species of mouse spiders and all are potentially deadly to humans. Recent studies have tended to suspect that most of the people who were suspected of being bitted by funnel web spiders, were actually bitten by mouse spiders. Some research is showing that their toxin is just as deadly as the more famous funnel webs too.

  • Michael Garde

    uumm how can the Yellow Sac Spider (found in australia) make the worlds most dangerous list but not make the Australias most dangerous list? (i seen one list after the other) and the sydney funnel web should be number 1

    • surfgatinho

      The article wouldn’t have been particularly interesting if it was just a repeat of the Australia’s most dangerous spiders so I thought I’d mix it up a bit.
      Not sure I agree with you on Sydney funnel web being #1 though. Wandering spider is much more venomous, equally aggressive and more likely to come into contact with humans.

    • sparksflyswifty

      No, the Brasilian Wandering spider’s toxin is fractionally more dangerous than the various Australian funnel webs species. There isn’t much in it though, it’s pretty damn close and not “much more venomous” as surfgatinho has suggested. Both spiders are very aggressive, and both can and do wander. In both cases, it’s the males that wander, the females stay underground all their lives. The males are smaller than the females, but usually have stronger toxins. The funnel web is particularly nasty because it will bite multiple times and generally injects the full dose of venom, unlike most other spider species. It also has very strong jaws and the puncture wounds from the bite can be very painful.

      The Redback spider is particularly docile in comparison, and in a lot of instances, doesn’t inject venom on biting, or only a small dose.

      A word on necrosis – recent research has shown that tissue necrosis from hobo spider/sac spider/wolf spider is due to the victim being allergic to the venom. Healthy persons who aren’t allergic to the toxin don’t suffer necrosis.

      There’s a lot of misnomers about spiders, and a lot of that is to do with fear of them. Know thy enemy! (well spiders aren’t our enemies, but the saying was apt to be used in the context!).

  • Blake

    While I can’t say anything about the venom of the hobo spider, they are definitely not aggressive. A lot of the hobo spider’s bad reputation is due to media and exterminators.

    • KittyFox

      I agree because when my sister was young she held a young hobo spider in her hands and it didn’t bite her.

  • Joel W

    I wonder if you can synthesize and modify the venom from the Brazilian Wandering spider to make an alternative to Viagra? Get on it, Pfizer competitors! I only demand a small fee for the inspiration.

  • Jay

    The Redback Spider is NOT a Black Widow Spider; they are two (2) different widow spiders. They have very similar habits and comparable neurotoxic venom. They look almost identical, except for the Redback’s dorsal stripe, but they are NOT the same spider.

  • Kaitlyn Taylor

    It may be true that it has powerful venom, but the simple fact that it can’t bite a human and that they’re an extremely shy spider that would rather run than bite, makes it not dangerous to humans, so this list (most DANGEROUS spiders) is not where it belongs. Were it a list of most VENEMOUS spiders, then yes the daddy long-legs should appear on it 🙂

    • John Hanson

      No totally myth

  • Kevin Bacon
  • Just found a camel spider in my office. And I’m from the south of Europe

  • John Hanson

    Absolutely not, they have no fangs or venom at all. In fact the only way they could harm even small creatures would be through ingestion.

  • Grant Bogner

    Plus, they’re not even spiders. They’re opiliones, and they’re completely harmless, although they CAN penetrate the skin. Their bite causes a slight burning sensation for a few seconds, but nothing more.