From funnel-web spiders to brown hermits, here are some of the deadliest spiders on the planet.
Spiders are one of the most successful arthropods on Earth, with their footprints on all continents except Antarctica. Not all of these eight-legged arachnids are venomous, but some are lethal to humans. From the infamous Black Widow to the super-deadly funnel-web spider, here are some of the deadliest spiders on the planet.
Brown hermit spider
The brown reclusive spider is one of the deadliest spiders in the world.
As the name suggests, brown hermit spiders are shy by nature and prefer to hide in dark, sheltered places. However, brown hermit spiders bite when they feel threatened, and their bites can be fatal. They are typically found in the southern and central United States, from southeastern Nebraska to southwestern Ohio, and from southern to northwestern Georgia to Texas.
Brown hermit spiders are dangerous to humans because their venom contains a toxin that can cause skin necrosis (decay). Most often, within a few hours of being bitten, burning and itching of the bitten site occur, as well as symptoms such as fever and nausea. In extreme cases, venom can cause severe reactions and even death, especially to vulnerable groups such as young children and the elderly.
Stray spiders
Even arachnologists have a hard time identifying stray spiders because there are many similar-looking spiders and the species itself is very different.
The tramp spider is part of the funnel-web spider family and can be identified by its light to medium brown color and multiple V-shaped patterns with its abdomen pointing towards the head. They are often confused with brown hermit spiders (and vice versa), but brown hermit spiders are much more dangerous for humans. While stray spiders are known to bite when they feel threatened, there is a lot of debate about how venomous they really are. So much so that the Centers for Disease Control and Prevention has removed them from the list of venomous spiders. However, caution is still exercised as stray spider bites can cause swelling and redness around them, which can affect young children more severely.
Stray spiders are not good at climbing, so you'll find their funnel-shaped webs on the ground. Geographically, they are found in western North America, the Pacific Northwest and the Great Basin, and throughout Europe to Central Asia.
Black Widow spider
The female black widow spider hangs upside down in her web with red hourglass markings on her abdomen.
Black Widow is one of the most venomous spiders in the genus Crested spiders, found on every continent except Antarctica. In North America, they are commonly found in southern Canada and the northeastern United States. You can identify a female black widow spider by its shiny black body and distinctly red hourglass shape below its belly. Male black widows are smaller, brown or gray in color, with small red spots and no hourglass lines.
While both male and female black widows are poisonous, only females are dangerous to humans. Black Widow's venom is reportedly 15 times stronger than that of rattlesnakes, although they don't release as much venom in their bites as rattlesnakes, so few people have died. That's not to say that being bitten by a black widow doesn't hurt! Those who are unfortunate enough to be bitten by Black Widow experience symptoms of nausea, fever, sweating, restlessness, muscle cramps, and difficulty breathing, which can last for days.
Brazilian stray spider
Known as the Brazilian red-haired spider, the Brazilian stray spider lives in the dry, wet tropical forests of Central and South America.
Brazilian stray spiders are often called armed spiders or banana spiders (because they tend to hide in banana transport) and you should definitely avoid them. They belong to the genus Phoneutria, which means "murderer" in Greek, a name that is apt because they are one of the most venomous spiders on Earth.
This arachnid is very aggressive, and Brazilian stray spiders do not camp outside, but instead search for prey on the ground in the jungle at night. If you find yourself in Central and South America, such as Costa Rica or Argentina, be careful! Their neurotoxic venoms are very painful and can affect the nervous system, causing increased sweating and drooling, loss of muscle control, breathing problems, and in some cases, unnecessarily long erections.
Yellow sac spider
It is the only spider in Europe whose bite force can penetrate human skin.
Yellow-sac spiders belong to the family of red chela spiders, and they may bite more easily than other types of spiders. These arachnids are found all over the globe, from the United States to Northern Europe, from South Africa to India, and even Australia and Japan. They are nocturnal predators and hide in small white cocoons during the day.
Yellow-sac spider bites are mildly toxic to humans, can be painful, and are sometimes misdiagnosed as brown hermit bites. Their venom can cause massive necrosis, as well as redness and ulceration around the bite site.
Brown widow spider
Both the Black Widow spider and the Brown Widow spider have red hourglass-like markings under their abdomen.
It looks a lot like its infamous "cousin" Black Widow, with hourglass-shaped markings on its abdomen, but there are some key differences. Brown widows are marked orange and yellow rather than red, and as their name suggests, they mainly have mottled and spiked tan and brown rather than a smooth appearance. The brown widow spider is thought to have originated in South America and is found all over the world.
Brown Widow's venom is less toxic than its black relatives. However, it can still be fatal. Although they don't release as much venom as Black Widow, bites from Brown Widow can still cause tooth decay due to its neurotoxic venom. Symptoms of lactation include pain, sweating, muscle stiffness, and vomiting.
Red Widow spider
An adult female red widow spider in her web.
The Red Widow spider lives primarily in the sand dunes of central and southern Florida and is another member of the infamous "widow" family. Their venom is as deadly as Brown Widow and Black Widow, but because they live far from human contact, there is no record of biting in the medical literature. The venom of female red widow spiders is a neurotoxin that is thought to cause prolonged muscle spasms.
The red widow spider has an orange-red head and legs, a black belly and a yellow circle around the red dot. Unlike its "cousin," Red Widow usually has one or two red markings.
Redback spider
Female red-backed spiders have a long red stripe on their back.
Due to its strikingly similar appearance, the redback spider was once considered a subspecies of the black widow spider, but it is a different species. Also known as the Australian Black Widow, you can find this creepy reptile in Australia, Southeast Asia, and New Zealand. Redback spiders have even been found in Japan, the United Arab Emirates and Belgium.
Highly poisonous, a bite by a female red-backed spider can be life-threatening. It infuses its fangs with a complex venom that causes severe pain at the bite site, in addition to sweating and goosebumps. Over time, these symptoms worsen and you may also experience redness, nausea, muscle twitching, headache, and fever. Severe cases may cause respiratory failure. Thankfully, in 1956 scientists released a red-backed spider antivenom, which was so effective that it was used even weeks after the initial bite. No deaths have been reported since.
Funnel web spiders
Funnel web spiders are among the deadliest spiders in the world.
Usually, in the spider world, female spiders are more lethal, but for funnel-web spiders, male spider bites are more toxic. Any attack must be treated quickly with antivenom, especially if a child is bitten. Several deaths have been recorded as a result of poisonous bites by funnel-web spiders, with deaths occurring within an hour of being bitten. However, no deaths have been recorded since antivenoms were developed in 1981. Funnel web spiders are mainly found in southeastern Australia (Sydney), but are also found in New Zealand, Chile and Europe.
Interestingly, animals such as cats and dogs can actually survive a funnel net bite — their bodies take about 30 minutes to neutralize the toxin — and only humans react so badly. This venom affects the nervous system, causing symptoms such as increased heart rate, numbness/tingling in the mouth, and difficulty breathing.
Six-eyed sand spider
Sand spiders live in barren deserts and are able to bury part of their body in the sand.
Found in the deserts of southern Africa, the six-eyed sand spider buries itself in the sand to ambush unsuspecting prey. The small, hard hairs that cover the spider help fix the grains of sand, increasing its camouflage effect. It is also known as the six-eyed crab spider because it has crab-like legs.
Toxicological studies have shown that the six-eyed sand spider is the most toxic of arachnids. Scientists have found that their venom contains proteins that can lead to tissue destruction, vascular leakage, and blood dilution. Antivenoms do not currently exist.
Mouse spiders
Male rat spider at Paravera Recreation Park, South Australia
The mouse spider is black in color, with thick legs and a distinctly bulbous head and chin area, which looks much scarier than its name sounds. One is found in Chile, another in South America, and the rest throughout Australia. They live in soil-covered burrows, sticking out from the top of hinged trap doors to attack their prey.
Their hard, large fangs can cause deep bites. However, although scientists believe that rat spider venom is highly toxic, it is rarely injected into it. With so few cases reported, it is thought that rat spiders do not use large amounts of venom and may even "dry bite". Fortunately, funnelweb spider antivenom has been shown to be effective against mouse spider bites.