The most venomous spiders in the world are not something you want to come across very often.
But their contribution to the world is actually extremely valuable, mainly due to their role as biological control agents, keeping down the populations of things like insects, mice and other vermin.
Pretty much anywhere you look on earth, you’ll be able to find spiders — you may not know it but there is always a spider within a few feet of you at any one time.
Various species of spider have populated the world since the Devonian Period 380 million years ago — far longer than humans have been around.
But despite their benefits, a lot of people are terrified of spiders. It’s easy to see why, as they’re not the most cuddly looking creatures and some of them are, well, deadly.
You can find out more about spider venom here, then scroll down to find out more about the most venomous spiders on the planet — if you dare…
11 Brown Recluse Spider
Length: 1.5 to 2.75 inches
Locations: Nebraska, Iowa, Illinois, Indiana, Texas, Georgia to Kentucky
This creepy-looking arachnid is known as “synanthrophic”, meaning that it has a close relationship with humans. Basically, it likes us because we attract its food.
The Brown Recluse is nocturnal and feeds at night, and because our artificial lights attract lots of bugs and insects, our homes are perfect places for it to find food just when it wants it.
The Brown Recluse is recognized through its oval-shaped abdomen, with dark brown, yellow, or greenish-yellow coloring.
When disturbed it injects its venom through the skin, leading to red swelling around the bite. This swelling then expands, while the skin close to the puncture wound hardens and can develop into a deep skin ulcer which is very painful.
The bite can lead to severe scarring and surgery may be required to remove the necrotic tissues. The Brown Recluse can live for six months without food or water.
It’s also a bit of an oddball in the spider word — as it also only has three pairs of eyes, rather than the normal four pairs of other arachnids. Creepy.
10 Yellow Sac Spider
Length: 0.25 to 0.5 inches
Locations: throughout North America
The Yellow Sac Spider enjoys living inside homes and outdoors under logs or thick leaves. They are called “sac” spiders because they do not weave webs.
Their young are created in silken tubes or sacs in the corners of walls and ceilings. The Yellow Sac Spider’s venom can leave human victims with lesions and dead skin tissues.
Their prey includes other spiders — no matter their size— insects, and insects. They also sometimes eat their own eggs.
9 Fringed Ornamental Tarantula
Length: 10 inches
Location: Western and Eastern Ghats, India
There are over 300 tarantula species throughout the world — some with leg spans of over 10 inches, including the Fringed Ornamental Tarantula.
They are also known as Indian Ornamental Tree Spiders or Indian Ornamental Spider, and have a powerful toxin that puts human victims into comas.
In their natural habitat as an arboreal spider, Fringed Orientals live in tree holes where they spin thick funnel webs. Their diet consists of flying insects of all varieties.
Due to their quick actions, they catch their prey on their own, and not through their webs, and use their venom to paralyze their prey.
If an adult is bitten by an Ornamental Spider, they will experience excruciating pain and muscle cramping.
8 Chinese Bird Tarantula
Length: 8 inches
Location: Southeast Asia
The Chinese Bird Tarantula is found in the rain forests of China and Vietnam.
Despite its name it doesn’t eat birds, instead feeding on insects like crickets, cockroaches and small rodents, and will only bite a human when provoked.
Its legs can span eight inches and it uses them to burrow deep beneath the ground, popping up to grab food with its large fangs.
Its venom contains neurotoxins and other compounds that are neurotransmitter blockers.
Adults and children have experienced severe nerve damage that rendered them unable to move after being bitten and sometimes the venom can cause death when left untreated.
7 Mouse Spider
Length: 1 inch to 1.4 inches
Location: Australia and New Zealand
The Mouse Spider received its name from its small mice-like features. It also moves quickly like a mouse and is stout and furry.
Its coloring is black or dark blue with a light grey patch on top. Males can have a bright red or orange area near its eyes.
Mouse Spiders live in silk-lined burrows with trap doors, which they create at 20 to 55 cm deep.
When the Mouse Spider senses the vibrations of a prey, like insects or larger animals — for example a human foot — near their trapdoor, they quickly lunge to bite and grab it with its long fangs.
The symptoms from a bite are similar to those from the Sydney Funnel-Web spider, and the funnel-web’s anti-venom is often given to individuals who have been bitten.
6 Brown and Chilean Recluse Spider
Length: 0.25 to 0.75 inches
Location: North America/Chile
The Brown Recluse Spider and Chilean Recluse Spider are very venomous, even with their small fangs.
Their venom bite in humans causes tissue destruction, kidney failure, and a large expanding wound, which can become gangrenous.
Both the Brown and Chilean Recluse spider’s bites can result in death, even when countered with anti-venom.
5 Redback Spider
Length: 0.12 in to 0.16 inches (male is smaller than female )
The Redback Spider is in the same family species as the Black Widow, below. Its venom is more toxic to some people than others.
For instance, in the more severe cases, a bite from the Redback can cause seizures, respiratory failure, and a coma.
Other less severe symptoms include nausea, muscle shakes, swollen lymph nodes, and migraine-type headaches.
The Redback spider has a red stripe down its back, with a prominent hourglass design on its abdomen.
4 Black Widow Spider
Length: 0.5 to 1.5 inches
Location: North America
Nearly everyone is familiar with the Black Widow spider, if not personally, then through references in songs and movies.
The female Black Widow lives up to its name because of its natural habit of eating its mate after sex.
In humans its venom causes “latrodectism” — severe muscle spasms and cerebral paralysis, and can cause death in children and elderly people.
There are several different versions of the Black Widow, and all have a brilliant red hourglass on their abdomen.
Anti-venom can be a life-saver for its bite and the damage that its venom can cause to the body.
3 Sydney Funnel-web
Length: 0.4 to 2 inches
Location: Australia, with cousins in the USA
The Sydney Funnel-web spider has large venomous fangs, with which it delivers large doses of venom when it bites.
This dark black spider is extremely dangerous to adults and children.
The Funnel-web spider is native to eastern Australia and has a venom called atracotoxin, which can kill a small child in just 15 minutes.
In adults the venom poison causes severe pain at the injection site, muscle spasms, fatigue, nausea and vomiting.
The Sydney Funnel-web spider is extremely aggressive and it will not only strike once, but several times before it moves away.
Its web is indicative of its name, as they create funnel webs in grasslands, corners of porches, and wherever there are small crevices.
2 Six-eyed Sand Spider
Length: up to 0.6 inches
Location: the deserts of the African continent and South Asia
The Six-eyed Sand Spider has a leg span of two inches and is extremely venomous, although it is not aggressive until disturbed.
The second most venomous spider in the world, its venom is purported to be more powerful than that of its cousin the Recluse species.
Unfortunately, there isn’t a direct anti-venom for its bite, therefore lengthy hospital stays are needed to combat all of its effects on humans.
Its bite causes horrific symptoms — mainly intravascular coagulation, resulting in blood clots throughout the body, which leads to bleeding from the skin and orifices, eventually leading to death.
1 Brazilian Wandering Spider
Length: 0.67 inches to 1.89 inches
Location: Brazil and outlying South American regions
The Brazilian Wandering Spider holds the Guinness Book of World Records title for the most venomous spider in the world.
It has a leg span of five inches and can inject up to 1.069 mg of its venom in one bite.
The Brazilian Wandering Spider is not friendly and will stand on its rear legs and fight if approached.
Its venom is a neurotoxin, which causes difficulty in breathing or asphyxiation and, within a few moments, death.
At lower concentrations the venom can also cause also “priapism” in men — a prolonged erection which can last for hours and days before leading to impotence.
Have you ever had an encounter with one of the most venomous spiders in the world? Let us know in the comments section below. Also check out some more spider pictures in our gallery.