Most Common and Dangerous Spiders in America

There are around 43,000 different spider species found all over the globe. Less than 30 species out of these are dangerous to humans. Spider venom is deadly for small animals. In humans, spider venom will produce skin lesions and allergic reactions. Often times the allergic reactions result in fatalities. It is true that death caused by spider bites in America is rare. Yet, it will be best to know about the different species. Even proper basic knowledge about some popular American species will help you to act effectively and accurately during an emergency.

If you can inform the hospital that the bite came from say, a WOLF SPIDER or a HOBO SPIDER without any doubt. Then, the doctors will be able to provide you with the appropriate antitoxin (antivenin) quicker in such a case. So, read on to know about some venomous spiders found in America.

Common American Venomous Spiders

1. Yellow Sac Spider

Its scientific name is Cheiracanthium inclusum. Other than America, they can be found Mexico and some parts of South America. They are found in outdoor foliage. During cold weather, they tend to take shelter insides homes. Thus, you can spot them indoors commonly. The range in body length is from 3 to 15 mm.

They are venomous and their venom is a cytotoxin. So, it is a type of substance that can either impair the functioning of cell or destroy a cell entirely. The bite will cause necrotizing lesion in rare cases. However, swelling and redness at the site of the bite are some common reactions.

You should know that they are not docile. A female spider may bite if she had to defend her eggs. Yellow sac spiders are known for building silken tubes under stones, in grass, or in leaves.

2. Black Widow

Its scientific name is Latrodectus mactans. This one contributed to more than 25,000 poison control center visits yearly in America. Besides the U.S., they are also found in some parts of Canada and Latin America. They are also common in West Indies.

You can find them building nest in different settings like burrows, woodpiles, or among plants that can support their web construction. The body is about 2.5 cm long. You will come across a female in most cases.

You can distinguish it from a HOBO SPIDER by spotting the yellow to reddish hourglass design seen on its spherical abdomen’s underside. You will feel the sensation of pinprick if bitten by it. The bite will cause mild paralysis of the diaphragm, resulting in difficulty during breathing. You may also deal with nausea and severe muscle cramping and pain. This is the emergency treatment method.

3. False Black Widow Spider

Its scientific name is Steatoda grossa. This one is a common species in the genus Steatoda. Besides America, you can find them in Europe and Australasia. Compared to a Black Widow, this one is less harmful. However, its bite (only female bites) is still extremely painful.

While the male ones will be around 10mm in size, the females are around 15mm. They are mainly brownish in color and come with pale marks. They are found mainly in gardens and dwellings. You can spot them under wood and rocks, and in fences, walls, and bark of trees.

Generally, they bite only when they feel the need to defend themselves. You will not feel the bite immediately. But, after just few minutes you will deal with burning sensation, radiating pain, swelling and redness that lead to a weal.

4. Wolf Spider

Its scientific name is Lycosidae. Besides America, they are found in Europe and north of the Arctic Circle. They can be around 2.5cm long and build tubular, silk-lined nest in ground.

A WOLF SPIDER is dark brown in color with pale markings or stripes along the body. This hairy spider can be seen near the floor level of a property. Outside, you can spot them under leaves, firewood, and stones.

It is actually very uncommon for it to bite if not provoked in any way. The venom is not that dangerous. You will have allergic reactions resulting in dizziness, nausea, and elevated heart rate. You will come in contact with its powerful and large fangs when bitten. So, you will face issues like swelling, redness, and bee-sting like sensation as well.

5. Brown Widow Spider

Its scientific name is Latrodectus geometricus. Common in the Gulf Coast states and California, they come from Africa and South America. They are also found in Australia, Japan, and Cyprus. Generally, they live in warm climates. You will spot them in old buildings, unused worn-out tires and automobiles, and shrubs.

You can identify it by its long legs, brown colored body. It has orange, yellow, white, black, or dark-brown markings on the abdomen. There will be an hourglass-shaped marking on the abdomen’s underside that is orange in color.

The potency of its venom is 2 times more than a black window’s. Yes, it injects a very small amount. Yet, the potent neurotoxin will affect your nerve endings. You will deal with sweating, vomiting, muscle rigidity and pain once bitten.

6. Recluse spider

Its scientific name is Loxosceles recluse. They are found in the southern and western United States. They are about 7mm in size. It is also known as violin spiders as it has a dark violin-shaped design on its body (back area).

You can spot them in different protected environments including rodent burrows and caves. Inside, you will find them in places like ceiling or wall voids, storage areas, attics, crawl spaces, and other such dark places around the house.

Avoid their bites as the venom can destroy blood vessels’ walls (near the bite’s site). It can even cause large skin ulcer, fevers, restlessness, and difficulty in sleeping. The venom attacks the phospholipid molecules. The bite painful wound site will have sore that takes many months to heal properly.

Other Venomous Spiders in the World

1. African six-eyed sand spider

It is found in deserts and other sandy places in Southern Africa. Its nearest relative is the Recluse spiders. Generally, it is yellow to reddish-brown in color and has distinct patterns.

On record, its venom is the most dangerous. The venom had powerful necrotic and haemolytic. It can cause rapid tissue destruction and blood vessel leakage. Rarely, they come in contact with humans and bite them without any provocation. It only hunts scorpions and insects that come close to it.

They blend well in sand because of the small hair present on them that can hold the sand particles. Unlike other ambush spider hunters, this one will bury itself under the sandy surface. It will hunt without digging a burrow.

2. Sydney funnel-web spider

This particular name was given to this species of spider as it builds web that is funnel-shaped. They build the web as burrows or to catch a prey. They wait in the narrow “funnel” for the prey to come in contact with its web.

They can grow up to 5cm across. They are black in color and can be identified by its lightly haired, shiny body.

The venom released by its bite is both potentially deadly to humans and other primates. The small male species have more potent venom than females. The mix of toxin present in the venom can kill a human in anywhere from 1 hour to 3 days. Since the 1920s, several deaths due to its bite have been recorded in Sydney.

3. Australian redback spider

It is considered as a “cousin” of Black window. It is native to Australia, yet, can be found in Japan, Belgium, and New Zealand. They are found in urban areas.

They have prominent red hourglass shaped mark or stripes on its back. Compared to males, this mark is more noticeable on females.

They are not aggressive. In fact, they “play dead” when disturbed. However, a female defending her eggs can become aggressive. The venom can cause swollen lymph nodes, rapid heartbeats, sweating, and pain.

In Australia, each year doctors take care of about 250 redback bites. However, the last human death due to its bite was recorded in 1956.

4. Brazilian wandering spider

This name was given to them as they are found wandering around the floor of the jungle during night time. As they are common in banana leaves, they are also known as banana spiders.

They are known for its defensive and aggressive posture. It will raise straight its front legs up into the air.

They are considered as the deadliest of all spider found all over the globe. The venom will affect the nervous system. So, if you are bitten, then you will deal with irregular heartbeat and salivation.

The venom can cause prolonged erections (painful) in men too. This is the reason why the venom is being tested for treating erectile dysfunction.


These were some common dangerous spiders found in America. Here, different spider species found around the world have been mentioned as well. By now, you can distinguish between different spiders like a WOLF SPIDER or HOBO SPIDER. Yes, learning about the different American spiders will help you to be well-prepared. Still, you should consider learning about them as it is actually very fascinating. So, it is highly advisable that you learn more about the kinds mentioned here and others found here.

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