Most spiders are feared more because they of their creepiness than because of their ability to inflict lasting harm on humans.
Some of the world’s most dangerous spiders are aggressive and will not hesitate to attack humans with little provocation. Most, however, will cower away and avoid conflict unless cornered—like in a shoe as a foot approaches, or in a shirt sleeve as an arm plunges in.
In the United States, about 60 out of 3,000 spider species are thought to have significantly harmed people.
Here’s a look at seven of the most dangerous spiders around the world.
7. Redback Spider, Latrodectus hasselti
Redback spider (Wikimedia Commons)
Location: All across Australia. It has spread via exports from Australia to New Zealand. It’s also been spotted across Southeast Asia and Japan.
Body size: Females 0.4 inches (1 centimeter), males 0.1 inches (3 to 4 millimeters)
About 250 people receive antivenom for redback bites each year. About 80 percent of bites have little to no effect, and most of the other 20 percent are painful for about a day but are not serious. The rare serious cases can include symptoms such as rapid heartbeat, headache, vomiting, and insomnia.
No fatalities have been recorded since an antivenom was introduced in the 1950s.
Redbacks don’t stray far from their webs, and most bites have occurred when people came into direct contact with the webs.
6. Sydney Funnel-Web Spider, Atrax robustus
Sydney funnel-web spider. (Shutterstock)
Location: Within a 100-mile (160-kilometer) radius of Sydney, Australia. Other species of funnel-web spiders are found throughout Australia.
Body size: Females 1.4 inches (3.5 centimeters), males 1 inch (2.5 centimeters)
Although the Sydney funnel-web spider has not killed anyone since an antivenom was introduced in 1981, it remains “an icon of fear and fascination for Sydneysiders,” according to the Australian Museum. The spider has caused more than 13 recorded deaths.
The fibers from its web are used in making optical instruments.
These spiders live beneath rocks and logs in forests and also in compost heaps or in the soil beneath houses. They prefer moist, earthy territory.
5. Six-Eyed Sand Spider, Sicarius hahni
A mature female six-eyed sand spider on the coast of Namibia. (Jon Richfield/Wikimedia Commons)
Location: South Africa
Body size: 0.5 inches (1.5 centimeters)
Size including legs: Up to 2 inches (5 centimeters)
This spider is unique in its ability to camouflage. It not only buries itself in the sand, but even above ground it looks like sand—until you see its crab-like legs scurrying. It has an exoskeleton with bristly hair-like structures that trap sand so the spider is coated in sand at all times.
It rarely bites humans, but its venom is powerful, able to kill a rabbit in a few hours. There are no recorded human fatalities from its bite. Its venom causes blood vessels to leak, tissues to break down, and eventually organ failure.
4. Brown Widow, Latrodectus geometricus
A brown widow spider in Los Angeles, Calif. (Matthew Field)
Location: Southern United States
Body size: Females 0.5 inches (1.5 centimeters), males 0.2 inches (6 millimeters)
Size including legs: Females 1.5 inches (4 centimeters), males 0.5 inches (1.25 centimeters)
The brown widow has venom twice as potent as its sister, the black widow. The brown widow does not inject as much venom, however, when it bites. It is a timid spider, and it sticks to secluded, protected areas. Brown widows have been found in outdoor garbage cans, under eaves, in mailboxes, in cluttered garages, under outdoor chairs, and other such places.
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3. Brown Recluse, Loxosceles reclusa
Brown recluse spider (Shutterstock)
Location: Southern and central United States
Body size: Females 0.4 inches (10 millimeters), males 0.3 inches (8 millimeters)
Size including legs: Females 1 inch (2.5 centimeters), males 0.75 inches (2 centimeters)
About once every five years, one serious, potentially fatal case, of a brown recluse bite occurs. Brown recluse venom contains a unique protein not usually found in the venom of poisonous animals. This protein causes dark lesions to develop around the bite, along with inflammation.
The immune system prevents blood flow to the area so the toxin does not spread through the bloodstream.
“Our bodies are basically committing tissue suicide,” Greta Binford, an associate professor of biology at Lewis and Clark College in Portland, Ore., told the University of Arizona News. “That can be very minor to pretty major, like losing a big chunk of skin. The only treatment in that case is usually to have a skin graft done by a plastic surgeon.”
The spider is found in sheltered places, such as woodpiles, under porches, or in little-used drawers. A person may not even feel the bite, though the pain may become severe several hours later. In rare cases, the venom can cause coma, kidney failure, and seizures.
The brown recluse is also called a fiddleback or violin spider.
2. Black Widow, Latrodectus mactans
A black widow spider on a farm in Georgia, USA. (James Gathany/CDC)
Location: Most abundant in the southern United States, but found throughout most of the Western Hemisphere.
Body size: Females 0.5 inches (1.5 centimeters), males 0.2 inches (8 millimeters)
Size including legs: Females 1.5 inches (4 centimeters), males 0.5 inches (1.25 centimeters)
The female black widow’s poison is 15 times more potent than a rattlesnake’s. The pain spreads rapidly through the body, followed by chills, nausea, trouble breathing, delirium, partial paralysis, and spasms.
About 5 percent of black widow attacks are fatal. In 2010, 2,168 bites were reported in the United States, 892 of which were treated in healthcare facilities. Most people recover within 24 hours with treatment, or a few days without professional treatment.
VIDEO: A brave fellow lets a black widow crawl on him. He cautions others not to try this, as he is accustomed to handling spiders properly.
1. Brazilian Wandering Spider, Phoneutria
Location: Brazil, with some species found all across Latin America. They have been known to hitch rides in banana shipments to the United States and other locations.
Body size: 0.7 to 1.9 inches (1.7 to 4.8 centimeters)
Size including legs: 6.75 inches (17 centimeters)
Guinness World Records has named the Brazilian wandering spider the most poisonous spider in the world. This spider is also aggressive. They fiercely attack, biting several times.
The Brazilian huntsman (Phoneutria fera), a species of wandering spider, is particularly dangerous. It has the most active neurotoxic venom of any spider in the world.
These spiders are also called banana spiders or armed spiders. Most deaths have occurred when young children were bitten.
