Understanding the Wandering Spider: Quick Essential Facts

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Wandering spiders are a group of venomous arachnids found primarily in South America.

Among these, the Brazilian wandering spider is particularly known for its potent venom and unique behavior. They are often referred to as “banana spiders” due to their frequent encounters with humans in banana plantations.

As a reader, you might be interested in learning more about these fascinating creatures, including their habitat, hunting techniques, and the effects of their venom.

In this article, we will delve into the world of wandering spiders and provide you with all the essential information to satisfy your curiosity.

Wandering Spider

Scientific Classification and Naming

The wandering spider belongs to the genus Phoneutria, which is a part of the Ctenidae family.

These spiders are known for their potent venom and aggressive behavior. Here is the scientific classification of the wandering spider:

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Subphylum: Chelicerata
  • Class: Arachnida
  • Order: Araneae
  • Family: Ctenidae
  • Genus: Phoneutria

Within the genus Phoneutria, two species are particularly noteworthy: Phoneutria fera and Phoneutria nigriventer, also known as P. nigriventer. These spiders are primarily found in South America and other tropical regions.

Phoneutria fera and P. nigriventer differ in some aspects. Let’s compare their features using a table:

FeaturePhoneutria feraP. nigriventer
Body lengthUp to 2 inches1.5-2 inches
LegspanUp to 6 inchesUp to 5 inches
ColorBrown to dark brownBrown with black abdomen
HabitatRainforests, banana treesForests, human dwellings
DistributionAmazon BasinBrazil, Argentina, Paraguay

Some key characteristics of the wandering spiders in the genus Phoneutria include:

  • Potent venom that can be dangerous to humans
  • Nocturnal hunters and are active at night
  • Equipped with long, spiny legs for capturing prey
  • Aggressive defenders of their territory

By understanding the scientific classification and differences between Phoneutria species, you can better appreciate the diversity and fascinating biology of these wandering spiders.

Identification and Appearance

Color and Size

The wandering spider, also known as the banana spider, has a distinctive appearance that can help you easily identify it in the wild.

They usually have a combination of hairy brown and black colors on their body. Their size can vary, but they are generally considered large spiders. Their size can range from 1 to 2 inches in body length.

Leg Span

When it comes to wandering spider’s leg span, these creatures can have an impressive reach. Their leg span can extend up to 5-6 inches.

Some key characteristics of a wandering spider’s legs include:

Habitat and Distribution


Wandering Spiders are known to inhabit various environments, including rainforests and tropical forests.

These spiders can adapt to different habitats based on their needs and availability of food sources. They prefer warm and humid places, as these conditions suit their growth and reproduction.

Geographical Coverage

Wandering spiders are found in Central and South America.

They live in forests from Costa Rica to Argentina, including Colombia, Venezuela, The Guianas, Ecuador, Peru, Bolivia, Brazil, Paraguay, and Northern Argentina.

They may also be present in some parts of the United States, particularly in the northern part of southern America.

However, they don’t inhabit countries like Australia. In summary, the Wandering Spider is mostly prevalent in the following areas:

  • South America
  • Central America
  • Southern parts of the United States

Types of Wandering Spiders

Here’s a brief description of the major types of wandering spiders.

Brazilian wandering spiders

Also known as armed or banana spiders, these spiders are nocturnal and don’t make webs.

They are known to have been transported outside of South America in banana shipments.

Phoneutria nigriventer

These spiders contain neurotoxins that can cause cerebral changes and breakdown of the blood-brain barrier.

Their venom is medically significant and has been used in manufacturing drugs. Their bites may be fatal to children.

Ctenus captiosus

Also known as the Florida false wolf spider or tropical wolf spider, this species is found in the United States.


Some species of these spiders are large and scary-looking, but they’re only mildly venomous. Their venom is comparable to a bee sting.

Other types of wandering spiders include: Acantheis, Acanthoctenus, Africactenus, and Afroneutria.

Cupiennius salei

Behavior and Diet

Aggression Level

Wandering spiders, as their name suggests, are known for their aggressive behavior.

While they won’t attack without provocation, if they feel threatened, they will not hesitate to defend themselves.

This is especially true during mating season.

Prey and Predators

In their natural habitat, wandering spiders primarily feed on insects and small vertebrates, such as:

  • Insects like ants and moths
  • Small amphibians
  • Reptiles

This diverse diet allows them to thrive in various ecosystems.

However, they are not top predators, as their natural predators include larger birds, mammals, and other spiders.

Nocturnal Activities

Wandering spiders are nocturnal creatures, which means they are active during the night.

During the day, they remain hidden in their retreats, often made from rolled-up leaves or small crevices.

At night, they leave their hiding spots to search for prey using their strong hunting skills.

Venom and Its Effects

Composition of Venom

The venom of the wandering spider is a complex mixture containing several toxic components.

Its main component is a potent neurotoxin, which can have severe effects on your nervous system1. Here’s a brief overview of its composition:

  • Neurotoxins
  • Proteins
  • Enzymes
  • Peptides

Symptoms and Severity

A wandering spider’s venomous bite can cause a wide range of symptoms, depending on the severity of envenomation. These symptoms may include2:

  • Mild to moderate pain
  • Redness and swelling at the bite site
  • Vomiting
  • Irregular heartbeat
  • Difficulty breathing
  • Blurred vision
  • High blood pressure

Some severe cases may result in life-threatening complications, such as respiratory failure or even death2.

Medical Treatment and Antivenom

If bitten by a wandering spider, it’s crucial to seek immediate medical attention. Treatment often involves the following steps:

  1. Cleaning and immobilizing the affected area
  2. Monitoring and managing the symptoms
  3. Administering antivenom if it’s available and appropriate, depending on the severity of envenomation3

Antivenom is specific to the venom of the wandering spider and can help neutralize its effects.

However, the availability of antivenom may be limited in some regions3.

Always remember that prevention is better than cure: learning how to identify and avoid wandering spiders is the best way to stay safe.

Reproduction and Mating

Mating Ritual

When it’s time for reproduction, the wandering spider undergoes an intriguing mating ritual.

The male spider performs a dance to attract the female by displaying his brightly colored legs and vibrating his body.

During the process, the male also produces a sperm web and transfers his sperm to the female’s reproductive organs using his pedipalps.

Egg Sacs and Offspring

After the mating process, the female wandering spider will create an egg sac to protect her eggs.

The sac consists of silk and can hold hundreds of eggs. She then attaches it to a safe hiding place, usually against a protective surface or within a secure web.

The female often guards the egg sac to ensure the protection of her offspring until they hatch.

Once the spiderlings hatch, they are known to be highly independent.

They disperse quickly and start their own journey, fending for themselves soon after emerging from the egg sac.

As they grow, they’ll go through a series of molts before reaching adulthood and beginning their own reproductive cycle.

Danger and Defense Mechanisms

The Wandering Spider is known to be one of the most dangerous spiders in the world.

Although they can potentially kill humans, fatalities are rare due to their reluctance to bite.

Oddly enough, their venom can cause an involuntary erection in men, alongside other painful symptoms.

Here are some ways the Wandering Spider protects itself and displays its dangerous nature:

  • Fangs: These spiders are equipped with strong, sharp fangs that can easily pierce human skin, allowing them to inject their venom with ease.
  • Venom: Their venom is potent and can cause severe pain, inflammation, and other adverse effects. In rare cases, it can even lead to death.

While interacting with Wandering Spiders, be cautious and observe them from a safe distance.

Knowing their defense mechanisms will help you respect their space and avoid any unpleasant encounters.

Remember, it’s essential to be informed and aware when dealing with these fascinating, yet dangerous creatures.

Comparison with Other Dangerous Spiders

Comparison to Black Widow

The black widow spider is notorious for its potent venom, but the wandering spider has a stronger venom overall.

Both spiders are capable of causing severe symptoms, but the black widow’s venom is primarily neurotoxic, affecting your nervous system.

In contrast, the wandering spider’s venom can cause both neurotoxic and cytotoxic effects, potentially damaging your nerves and cells.

  • Black Widow:
    • Potent neurotoxic venom
    • Red hourglass marking
  • Wandering Spider:
    • Stronger venom (neurotoxic and cytotoxic)
    • No distinct marking

Comparison to Brown Recluse

The brown recluse spider is known for its necrotic venom that can lead to tissue damage and sometimes requires medical intervention.

While both the brown recluse and wandering spider can produce venomous bites, wandering spiders are considered more dangerous due to the potency of their venom and the severity of their bite symptoms.

  • Brown Recluse:
    • Necrotic venom
    • Dark violin-shaped marking
  • Wandering Spider:
    • Stronger venom (neurotoxic and cytotoxic)
    • No distinct marking

Comparison to Wolf Spider

Wolf spiders are frequently mistaken for more dangerous spiders due to their size and appearance.

Although they can bite, their venom is not particularly potent and generally only causes mild itching, redness, and swelling.

In comparison, the wandering spider’s venom is far more dangerous, and its bite can result in serious symptoms, requiring immediate medical attention.

  • Wolf Spider:
    • Mild venom
    • Large and hairy
  • Wandering Spider:
    • Stronger venom (neurotoxic and cytotoxic)
    • Smoother appearance

Comparison to Sydney Funnel-Web Spider

The Sydney funnel-web spider is another highly venomous spider known for its potentially lethal bites.

While both spiders possess powerful venom, the wandering spider has a broader range of symptoms due to the combination of neurotoxic and cytotoxic effects.

 Wandering SpiderSydney Funnel-Web Spider
VenomNeurotoxic and cytotoxicMainly neurotoxic
LocationSouth and Central AmericaAustralia
AggressivenessHighly defensiveHighly aggressive and defensive
SymptomsPain, swelling, hypertension, and morePain, drooling, muscle spasms

In conclusion, wandering spiders are more dangerous than wolf spiders but their venom’s effects are more varied compared to black widows, brown recluses, and Sydney funnel-web spiders.

Be cautious around these spiders and seek medical help if bitten.

Interesting Facts and Guinness World Records

The Wandering Spider, also known as the Brazilian Wandering Spider, is a fascinating creature that has caught the attention of many.

They belong to the genus Phoneutria, which means “murderess” in Greek, giving you an idea of their potency. Let’s explore some interesting facts about this spider and its place in the Guinness World Records.

First, you might be curious about their venom. The Wandering Spider is known for having one of the most potent venoms among spiders.

In fact, it holds the Guinness World Record for the most venomous spider. Their venom contains a potent neurotoxin that can cause severe symptoms, including difficulty breathing, high blood pressure, and intense pain.

Apart from their venom, their behavior is also quite intriguing. These spiders are called “wandering” because they are known for actively hunting their prey rather than spinning webs to catch them.

They are mostly nocturnal creatures and, during the day, can be found hiding in logs or dark crevices.

Here are a few more notable characteristics of the Wandering Spider:

  • Females are larger than males, with a body length of up to 1.6 inches (4 cm).
  • They have eight eyes, arranged in two rows, which help them in hunting.
  • The Wandering Spider is primarily found in Central and South America, particularly in Brazil.
  • They are known to show aggression when threatened.

While the Wandering Spider is a marvel of the arachnid world, it’s essential to keep a safe distance from them due to their venomous nature.

However, their unique characteristics and record-breaking venom potency make them a fascinating subject for those interested in the natural world.

Prevention and Safety Measures

To protect yourself from wandering spiders, there are some simple safety measures you can take.

Firstly, be cautious in areas where these spiders may live, such as dark and warm spaces. For example, avoid reaching into crevices or lifting piles of wood without inspecting them first.

Always wear appropriate shoes when outdoors, particularly in wooded or grassy areas. This can help prevent bites on your feet or ankles.

Reduce the risk of wandering spiders entering your home by sealing gaps and cracks. This minimizes the chance of the spiders finding a way inside.

Regularly clean your living spaces, paying special attention to dark and hidden areas. By maintaining a clean environment, you’ll discourage wandering spiders from making themselves at home.

When out in nature, avoid disturbing spider habitats like webs or egg sacs. This can prevent agitating wandering spiders, reducing your chance of accidental encounters.

Remember, wandering spiders can be dangerous, but by taking these precautions, you can significantly reduce your risk of encountering them or being bitten. Stay safe and always be aware of your surroundings.


In summary, wandering spiders, particularly those in the genus Phoneutria, are a group of venomous arachnids predominantly found in Central, South America and parts of Southern United States.

These spiders, including the Brazilian wandering spider, are known for their potent venom, nocturnal hunting habits, and aggressive defense mechanisms.

Their venom, containing neurotoxins and other components, can cause severe symptoms in humans, making them one of the most dangerous spider species.

Despite their fearsome reputation, fatalities are rare, and they play a vital role in their ecosystems.

It’s important to respect their space and take preventive measures to avoid encounters. Understanding these spiders’ behavior, habitat, and characteristics can help in appreciating their role in nature while ensuring safety.


  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2857337/

  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3851068/ 2

  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6560916/ 2

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about wandering spiders. Scroll down to have a look at some of them.

Letter 1 – Wandering Spider from Ecuador

Ecuador Spider
I took a very poor picture of a large, hairy, white spider in the rainforest of Acuador near the Napo River. The guide referred to it as a Capuchin Spider. I know there are Capuchin Monkeys but can’t find anything on a spider by this name. Can you tell me what the name of this spider is? See attached.
Thank you,
Michele Hughes

Hi Michele,
There is a resemblance to the Dolomedes Fishing Spiders, and finding it near a river lends credence to that possibility. Eric Eaton noticed this posting and has this to say: ” Ok, the spiders from Ecuador and Costa Rica: They are most likely NOT wolf spiders, but wandering spiders, either in the family Ctenidae or Sparassidae. They tend to be more common, and even larger than, wolf spiders in the tropics. At least one species, Phoneutria fera, is extremely aggressive, with potentially deadly venom. Do not mess with large spiders in Central and South America! The venomous types are very difficult to distinguish from harmless species, and in any event, a bite is going to be really painful. These spiders sometimes stow away in bananas, houseplants, and other exported goods, so they can show up in odd places. Be careful where you put your hands.”

Update:  May 14, 2013
We now have a confirmation that this is a Wandering Spider,
Phoneutria fera, and it is a dangerous species.  See Encyclopedia Britannica and Animal Corner.

Letter 2 – Brazilian Wandering Spider: Most Venomous Animal

Brazilian wandering spider
Hi guys,
I searched your site hi and low trying to identify this little beauty I found when clearing out my shed the other day. I caught it in a jar, photographed it and let it go out the back and when I released it it actually ran after me. Every time I stopped it would change direction and come after me again. Eventually, after going through several links, I have identified it as a Brazilian Wandering Spider Phoneutria nigriventer and to quote from Wikipedia ” The Brazilian wandering spiders appear in the Guinness Book of World Records 2007 for the most venomous animal. These spiders are notorious both due to their toxic venom, and because they are not reluctant to attack people who appear threatening. ” After reading this I thought I should have released it a bit farther from home.

Hi Martin,
We are happy you were able to write to us after your encounter with this Brazilian Wandering Spider and are thrilled to be able to post your story and photos to our site. We started to research, and our first hit has a different species name. Phoneutria fera is described as: “The Brazilian Wandering Spider is not for the ‘pet keeper’. Brazilian Wandering Spiders are extremely fast, extremely venomous, and extremely aggressive. These large and dangerous true spiders are ranked among the most venomous spiders known to man. In fact, the Brazilian Wandering Spider is the most venomous spider in the New World! In South America, these true spiders are commonly encountered in peoples’ homes, supposedly hiding in peoples’ shoes, hats, and other clothes. The Brazilian Wandering Spider does not remain on a web, rather, it wanders the forest floor, hence the name.” Our favorite information on Wikipedia is that Phoneutria is Greek for “murderess”. Here is one final tidbit about the effect of the bite of the Brazilian Wandering Spider on the human male.

Letter 3 – Possibly Wandering Spider from Ecuador

Subject:  Large spider on a palm trunk
Geographic location of the bug:  Macas, Ecuador (Ecuadorian Amazon)
Date: 02/14/2018
Time: 08:29 PM EDT
Your letter to the bugman:  We came across this while hiking in the jungle.  Wasn’t able to find a name for it, but the local person we were with suggested it could jump.
How you want your letter signed:  Mike Edgerton

Wandering Spider, we believe

Dear Mike,
This is really an interesting Spider, but other than to say it appears to be a hunting spider that does not build a web to entrap prey, we aren’t sure about its identity.  Many hunting spiders can jump quite well.  It looks very much like the spider in a posting in our archives, also from Ecuador, that we identified as possibly a Wandering Spider in the genus
Phoneutria, a venomous and potentially dangerous genus.  The spotted legs on your individual look like the spotted legs on an individual in an image on Wikipedia of a Wandering Spider in the genus Phoneutria.  There are many images of Brazilian Wandering Spiders on Primal Shutter and we believe that might be a correct identification for your individual.

Thank you for the information.  After reading more about the spider, I’m glad it didn’t jump!

Letter 4 – Possibly Wandering Spider from Ecuador

Subject: Unknown spider
Location: Mindo Ecuador
April 11, 2015 7:31 pm
Hey Its Carl again from the night walks in the cloud forest Ecuador, could do with some help identifying the family and species of this spider.
Also struggling with this larvae and praying mantis.
Signature: Thanks Carl

Possibly Wandering Spider
Possibly Wandering Spider

Dear Carl,
We believe, though we are not certain, that this might be a Wandering Spider in the genus
Phoneutria, and you may read more about Wandering Spiders on the Museum für Naturkunde Karlsruhe website where it states:  “There is no doubt that the venom of some of the species is quite potent for mammals, including humans.”  We eagerly welcome additional opinions on this identification.  Perhaps Cesar Crash of Insetologia can provide something.  In the future, please submit a single species per submission form as it makes it extremely difficult for us to categorize postings with multiple species.

Letter 5 – Wandering Spider from Belize

Subject:  Wandering Spider from Belize
Location:  Punta Gorda, Belize
May 21, 2017
Hello Daniel:
I continue to check your site regularly (still one of my favourites) but it’s been a while since I offered something for posting. I have been photographing a lot of spiders recently and have developed quite a fondness for wandering spiders (Family Ctenidae). I always look for them when we travel down to Central or South America. They are not hard to find but you generally have to look for them after nightfall. The attached photo is of a wandering spider (Cupiennius salei), one of many encountered on a night hike in a forest near Punta Gorda, Belize, earlier this year. I had already taken one to two photos of this one when it suddenly lunged out of frame to capture this hapless, and somewhat surprised looking, cricket. Have a great summer.

Wandering Spider eats Cricket

Hi Karl,
Thanks for allowing us to post your excellent image of a Wandering Spider,
Cupiennius salei.  The species is pictured on iNaturalist.


  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

    View all posts
  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

    View all posts
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