Brazilian Wandering Spider Bite: Is It Poisonous? What You Need to Know

The Brazilian wandering spider, known scientifically as Phoneutria, is a genus of spiders native to South and Central America.

They have garnered attention for their venomous bite, which can cause various symptoms and has the potential to be fatal.

This article will delve into the nature of the Brazilian wandering spider’s bite and its potential effects on humans.

Brazilian wandering spiders are notorious for having one of the most venomous bites among spiders in the world.

Brazilian Wandering Spider Bite

The severity of a bite’s effects is dependent on the amount of venom injected, and in some instances, the bite might not be as harmful as anticipated.

However, it is essential to be aware of the possible symptoms and seek immediate medical attention if bitten.

Some symptoms of a Brazilian wandering spider bite may include pain at the bite site, difficulty breathing, blurred vision, and sweating.

In severe cases, the bite can also cause high blood pressure, vomiting, and even death.

Prompt treatment can help mitigate the potential harm caused by these venomous bites and prevent long-lasting health consequences.

Brazilian Wandering Spider: Overview


The Brazilian wandering spider, also known as banana spiders, can be found primarily in South America. They prefer:

  • Tropical forests
  • Subtropical areas
  • Human settlements

Physical Characteristics

Brazilian wandering spiders have the following features:

  • Size: Up to 2 inches (5 cm) in body length
  • Leg span: Can reach up to 6 inches (15 cm)
  • Hairy: Present on their legs and abdomen
  • Color: Varies from brown to black, with some species showcasing red or orange patterns

Phoneutria nigriventer is one species within this group.

Source: Pavel Kirillov from St.Petersburg, Russia, CC BY-SA 2.0, via Wikimedia Commons
Brazilian Wandering Spider

Source: Pavel Kirillov from St.Petersburg, RussiaCC BY-SA 2.0, via Wikimedia Commons


These spiders demonstrate unique behavior:

  • Nocturnal: They’re more active at night.
  • Aggressive: They have a defensive posture when threatened, which includes lifting their front legs.
  • Venomous: They possess a potent venom that can be dangerous to humans.

Table: Brazilian Wandering Spider vs. Common House Spider

FeatureBrazilian Wandering SpiderCommon House Spider
SizeUp to 2 inches (5 cm)0.2 – 0.4 inches (0.5 – 1 cm)
Leg SpanUp to 6 inches (15 cm)0.4 – 0.8 inches (1 – 2 cm)
VenomPotent, potentially harmfulHarmless
HabitatSouth America, tropical and subtropical areasWorldwide, indoors

The Venomous Bite

Venom Composition

The Brazilian wandering spider, also known as Phoneutria, contains a complex cocktail of toxins in their venom. Some of the critical components include:

  • Neurotoxins
  • Insecticidal peptides
  • Pain-inducing substances

Envenomation and Its Effects

When a Brazilian wandering spider bites, it injects venom that can lead to various symptoms such as:

Although bites are rarely fatal, serious complications can arise when left untreated, potentially leading to death.

Comparison with Other Venomous Spiders

SpiderLocationPotency of Venom
Brazilian Wandering Spider / PhoneutriaCentral and South AmericaHighly venomous, potentially fatal
Black Widow / LatrodectusNorth America, other parts worldwidePotent neurotoxic venom, rarely fatal
Brown Recluse / LoxoscelesNorth AmericaNecrotic venom, can cause severe skin damage
Sydney Funnel-Web SpiderAustraliaExtremely venomous, can be lethal
Yellow Sac SpiderNorth AmericaLow risk, bites may cause mild symptoms

The Brazilian wandering spider is considered one of the deadliest spiders due to its potent venom.

However, antivenom is available for its bite, significantly reducing the risk of severe complications.

In comparison, other venomous spiders like the black widow, brown recluse, and Sydney funnel-web spider are also known for their potent venom but have varying severity of symptoms.

Source: Bernard DUPONT from FRANCE, CC BY-SA 2.0, via Wikimedia Commons
Brazilian Wandering Spider

Source: Bernard DUPONT from FRANCECC BY-SA 2.0, via Wikimedia Commons

Symptoms and Treatment of Brazilian Wandering Spider Bites

Recognizing the Bite

Recognizing the bite of the Brazilian wandering spider is crucial for seeking proper medical attention.

The main signs of a Brazilian wandering spider bite are:

  • Redness and swelling around the bite area
  • Intense pain at the bite site

Immediate and Long-term Symptoms

After being bitten by a Brazilian wandering spider, you may experience immediate and long-term symptoms.

Some common immediate symptoms include:

  • Excessive sweating
  • High blood pressure
  • Numbness, usually around the bite area

Brazilian wandering spider bite symptoms can escalate and result in more severe complications like envenomation.

Long-term symptoms can range from:

  • Muscle pain or cramping
  • Abdominal pain
  • Respiratory distress

Prevention and Safety Tips

Avoiding Bites

Brazilian wandering spiders can easily be spotted due to their large body length and venomous bite.

To avoid bites from these spiders, follow these tips:

  • Keep an eye out: Be cautious in areas where spiders are common.
  • Protective clothing: Wear long-sleeved shirts, pants, gloves, and boots when in areas with spider activity.
  • Stack materials properly: Minimize empty spaces between stacked materials to reduce hiding spots for spiders.

What to Do if Bitten

If you suspect a bite from a Brazilian wandering spider, take the following first aid steps:

  • Clean the bite area with soap and water
  • Apply a cold pack to the bite site to reduce swelling
  • Antivenom is available for Brazilian wandering spider bites
  • Proper treatment can minimize long-term effects and complications
  • Delayed treatment may worsen symptoms and lead to severe complications

Unfortunately, antivenom may not be readily available in certain regions. It is important to contact the health authorities immediately, who can help coordinate procurement of the antivenom.

It’s important to note that immediate treatment is crucial as Brazilian wandering spiders are venomous and their bites can lead to life-threatening complications.

Source: Rodrigo Tetsuo Argenton, CC BY-SA 4.0, via Wikimedia Commons
Brazilian Wandering Spider

Source: Rodrigo Tetsuo ArgentonCC BY-SA 4.0, via Wikimedia Commons

Frequency of Bites

While the Brazilian wandering spider is notorious for its venomous bite, actual incidents of bites on humans are relatively rare.

These spiders are nocturnal and tend to avoid populated areas during the day.

However, due to their wandering nature, they sometimes find themselves in human habitats, especially in rural or suburban areas close to their natural habitats.

Most bites occur when the spider feels threatened or cornered.

It’s worth noting that not every bite results in envenomation; sometimes, the spider delivers a “dry bite” without injecting venom.

Nevertheless, given the potential severity of a venomous bite, any encounter should be treated with caution.

Interesting Brazilian Wandering Spider Facts

Spider Mating and Reproduction

The Brazilian wandering spider or armed spider, scientifically known as Phoneutria fera, is known for its unique mating and reproduction habits.

These arachnids, like other spiders, engage in an elaborate mating dance:

  • Males approach females cautiously
  • Present a gift (usually prey like crickets)
  • Perform vibrations and touches

Once successful in their ambush, males deposit sperm in a female’s reproductive organ through their specialized pedipalps.

Female Brazilian wandering spiders create silk egg sacs to protect their offspring.

These egg sacs can contain up to 1,000 eggs, ensuring the survival of the species.

Unique Uses of Spider Venom

Brazilian wandering spider venom is one of the most potent in the world. The venom has an impact on the nervous system and can cause symptoms similar to a beesting.

However, researchers have found potential uses for this venom, specifically in treating erectile dysfunction.

A peptide in the spider’s venom called Tx2-6 can cause erections.

Studies have shown that this peptide could be a potential alternative to conventional erectile dysfunction treatments.


The Brazilian wandering spider, native to South and Central America, is renowned for its potent venom, making it one of the world’s most venomous spiders.

While their bite can lead to severe symptoms, including pain, blurred vision, and even death, timely medical intervention can mitigate these effects.

Despite their fearsome reputation, these spiders play a vital role in their ecosystem.

Their unique behaviors, from nocturnal habits to intricate mating dances, make them a fascinating subject of study.

As with any venomous creature, understanding and respecting their habitat is key to coexistence.

Reader Emails

Over the years, our website, has received hundreds of letters and some interesting images asking us about Brazilian wandering spiders.

Scroll down to have a look at some of them.

Letter 1 – Wandering Spider from Costa Rica

Subject: Costa Rica spider
Location: Costa Rica
April 2, 2017 5:13 pm
Any idea of what Genus this spider this is? Found in costa rica in October…
Signature: Thank you

Wandering Spider

We believe this is one of the potentially dangerous Wandering Spiders in the family Ctenidae based on this Photographers Direct image.

Thank you for answering! I’m surprised that we didn’t stumble around more dangerous things. We did find a poison dart frog and a monkey skull that fell from a tree…
See my iNaturalist site at:
– Sarka

Letter 2 – Wandering Spider from Costa Rica

spider in my shoe
Hi guys,
Here’s a spider that jumped out of my sandal when I put my foot into it. This was in January 2005 at the Serena park station in Corcovado National Park, Costa Rica. Thanks for your help!
Reisa Latorra

Hi Reisa,
Back in February 2006, we received two letters with images of spiders from Costa Rica and Ecuador. At that time, we identified them as Wandering Spiders. Eric Eaton wrote: “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.”

We found a site with an image of Phoneutria fera, and the coloration is different, but the body shape is very similar.


  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. 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.

  • 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.

1 thought on “Brazilian Wandering Spider Bite: Is It Poisonous? What You Need to Know”

  1. This is Phoneutria boliviensis – the only Phoneutria that occurs in Central America. It seems that this species is considered to be the least dangerous of its genus. All the same, I would not care to be bitten by one.


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