Deadliest Spiders in the World

Brazilian Wandering Spider

The Guinness Book of World  Records considers the Brazilian wandering spider to be the world’s deadliest spider.The Brazilian Wandering Spider, also known as the “ Banana Spider”, can be found in the jungles of South America. It does not have a web like standard spiders and can be found wondering on the jungle floor, hence its name. Though the jungle is this spiders natural habitat it is also commonly found in peoples homes. This spider is a very aggressive spider and tends to be nervous. This spider is commonly found hidden in the vegetation of banana trees and has been found stowed away in banana crates. This spider is known to be the most deadly spider in the Americas. The venom of this spider can be fatal to a mouse in a dose as small as 0.006mg! The Brazilian Wandering Spiders venom is also a neurotoxin and is very painful due to it release of serotonin. An interesting side effect of this spiders bite is that it is known to cause priapism, an erection that can last longer than four hours.

The Redback Spider

The Redback spiders live everywhere throughout the Australian continent. Female Redback spiders are black in color with a very apparent red or orange stripe that is visible on the back of the spider. The female Redback spider is dangerous and almost always connected to human deaths. Redback spider bites cause severe pain at the site of the bite and cause other symptoms to include: sweating, muscular weakness, vomiting, and nausea. Redback spider venom is a neurotoxin that affects the neurotransmitters causing there depletion. The Redback spider has caused several reported deaths of bitten human beings but none have died since the release of an antivenom. Over 250 bites receive antivenom treatment each year with many more cases most likely go unreported.

The Tree-Dwelling Funnel-Web Spider

The Tree-dwelling Funnel-web spider is also a resident of Australia though this spider is most commonly found on the east coast of the continent. Unlike the Redback spider the male Tree-dwelling Funnel-web spider is the killer, with venom five times as deadly as the female of the species. The body of the spider is glossy in nature with a color of either black or brown. The Tree-dwelling Funnel-web spider is extremely aggressive standing up on it hind legs when threatened and exposing their fangs. The venom of this impressive spider is a neurotoxin that cause the nerves to begin to fire rapidly. The bite of this spider can result in the following symptoms: salivation, muscle twitching, sweating, and tearing of the eyes. Many deaths have occurred from the bite of The Tree-dwelling Funnel-web spider before the introduction of an antivenom but even with the antivenom available the bite can be life threatening without immediate medical attention. The most interesting thing about the venom of these spiders is that most animals seem to be immune to their poison but it is extremely toxic to human beings and monkeys. 

Brown Recluse Spider

The Brown Recluse Spider, although nowhere near as deadly as the other spiders on this page, also deserves respect. The Brown Recluse spider is a small brown spider with a backwards violin shaped mark on the back of his head. This mark also led the spider to be known as the “ fiddle-back spider”. This spiders venom causes ulceration. The Brown Recluse’s bite does not tend to be painful at the time of the bite and some people will not even know they have been bitten. In the first few hours the bite will only appear small and red like a standard bug bite but within 24 hours will begin to swell and blister. If bitten in fatty tissue a deep lesion will occur that may not heal for several years! These bites without proper care have been known to lead to amputation of affected limbs. It is very likely that many people died of infection from the spider bites before the introduction of modern medical care. Below is a photo a Brown Recluse bite.

Black Widow Spider

The Black Widow Spider is known as the deadliest spider in North America. The female of the species is a very glossy black with an hourglass present on the thorax. The hourglass mark is usually red but can range from yellowish to orange in color. The male of the species is smaller than the female and is not dangerous. The black widow spider venom is a neurotoxin. The bite of the Black Widow is not generally known to be painful at the time of the bite but the bite will swell and two small fang marks will be seen. The symptoms of the bite are painful. The symptoms of the Black Widows bite include: localized pain in the back and abdomen, sever cramping of the abdominal muscles, nausea, labored breathing, tremors, profuse perspiration, high blood pressure, restlessness, and fever. Though most bites do not lead to serious long term side effects they have been known to lead to death.