What is the World's Most Poisonous Spider?

Many spider bites go unnoticed or cause only minor irritation -- unless a person is allergic to spider venom or the venom is poisonous.
Individuals who receive a bite from a potentially dangerous spider should proceed with caution.
Bites from poisonous spiders can cause extreme illnesses.
The poison of a Black Widow is potent.
Funnel web spiders are among the most dangerous to humans.
Being bitten by a black widow spider typically only causes death in cases where the victim has an allergic reaction.
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  • Written By: Tricia Ellis-Christensen
  • Edited By: O. Wallace
  • Last Modified Date: 02 July 2015
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There are a lot of rumors and misinformation on the contenders for the world's most poisonous spider. One persistent rumor is that the daddy long legs is the most poisonous spider; but, the rumor goes, that its mouth is too small to bite people. This isn’t true and has been disproved by many scientists. There’s a suggestion that the spider venom secreted from a daddy long legs would probably not make people very ill even if they were injected with it.

A big question in determining the world's most poisonous spider is whether the venom excreted by the spider would actually make humans sick. There are plenty of poisonous spiders that are highly toxic to their normal prey, but wouldn’t do much to the people they bite. If you’re only considering the most poisonous spider to humans, that spider is not, as many think, the black widow. Black widow bites are rarely fatal. Death may occur if the person who is bit is allergic. More commonly, people who are bit by a black widow suffer some pain and illness.


For humans, the two most dangerous spiders are brown recluses and funnel web spiders. Brown recluses are found in a few areas of North America, and funnels webs are located on the Australian continent in fairly defined areas. Both spiders have venom that can cause extreme illness. If small children receive a bite, fatality can result. It should be noted that instant fatality from a spider bite is extremely rare. Compared to the huge number of spider bites from some of the world’s most poisonous spiders, fatalities are extremely minimal.

Death rates on bites from another competitor for world's most poisonous spider, the Brazilian Wandering Spider, help us get to the truth of the danger of these spiders. Fatal bites occurred in less than 1% of the total number of reported bites. With the funnel web spider, people treated at hospitals for bites tend to require antivenin only about 10% of the time. When many spiders bite they inject little to no venom, though this may vary from bite to bite and spider to spider. In many cases, when people receive poisonous spider bites, they need some medical attention but don’t receive antivenin shots.

Those who receive a spider bite from a potentially dangerous spider should proceed cautiously. It’s better to get medical help, and if possible to bring the offending spider to the treating professional. It can be challenging to identify which spiders are actually poisonous and which ones are merely look-a-likes. It’s better to be safe and receive proper treatment to avoid potentially dangerous or life-threatening complications.


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Post 4

in biological terms, you're actually looking for the most venomous spider in the world. Poisonous means something that secretes toxins or produces them internally and will kill you if eaten or licked, e.g. certain fish and frogs/toads.

Venomous animals store their toxins and introduce them to the victim by biting or stinging.

Post 3

Just to correct this article a little bit. Spiders are not poisonous -- they are venomous. common mistake easily made by quite a lot of people.

Post 1

Funnel Web Spiders are not kin to Wolf Spiders. Wolf Spiders belong to the suborder Araneomorphae while Funnel Web Spiders belong to the suborder Mygalomorphae. There are vast differences in taxonomy of the two spiders. The wolf spider is more closely related to other Araneomorphs such as Latrodectus Mactans (Black Widow) while the Funnel Web would be more closely related to other Mygalomorphs (though a distinctly different family; the Hexathelids) such as the Theraphosids (tarantulas).

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