what is a wandering spider

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Brazilian Wandering Spider

The Brazilian Wandering Spider (Phoneutria fera) is an aggressive and highly venomous spider . It was first discovered in Brazil hence its name. However, this genus is known to exist elsewhere in South and Central America .

The Brazilian Wandering spider is a member of the Ctenidae family of wandering spiders.

The Brazilian Wandering spider appeared in the Guinness Book of World Records 2007 for being the most venomous animal .

In this particular genus, there are five known similar species whose members are also highly venomous. They include some of the relatively few species of spiders that present a threat to human beings.

Brazilian Wandering Spider Characteristics

The Brazilian wandering spider can grow to have a leg span of up to 4 – 5 inches. They are large hairy spindly-looking spiders who have eight eyes, two of which are large. Brazilian wandering spiders are fast-moving spiders, their legs are strong and spiny and they have distinctive red jaws which they display when angered.

The Brazilian wandering spider is not a Tarantula . Brazilian wandering spiders are not even in the same family group. Tarantulas are harmless to humans and are mostly ambush killers who wait for prey to come to them. Brazilian wandering spiders are active hunters. Brazilian wandering spiders and Tarantulas do have one thing in common, however, they do not eat bananas.

Brazilian Wandering Spider Habitat and Spider Webs

The Brazilian Wandering spider is so-called because it wanders the jungle floor, rather than residing in a lair or maintaining a web. This is another reason it is considered so dangerous. In densely populated areas, the Brazilian Wandering spider will usually search for cover and dark places to hide during daytime, leading it to hide within houses, clothes, cars, boots, boxes and log piles. This usually causes accidents when people disturb them.

The Brazilian Wandering spider is also called the ‘banana spider’ as it is occasionally found within shipments of bananas. As a result, any large spider appearing in a bunch of bananas should be treated with due care.

Brazilian Wandering Spider Diet

Adult Brazilian Wandering spiders eat crickets, other large insects, small lizards and mice. Spiderlings of this species eat flightless fruit flies and pinhead crickets.

Brazilian Wandering Spider Reproduction

All spiders produce silk, a thin, strong protein strand extruded by the spider from spinnerets most commonly found on the end of the abdomen. Many species use it to trap insects in webs, although there are many species that hunt freely such as the Brazilian Wandering spider. Silk can be used to aid in climbing, form smooth walls for burrows, build egg sacs, wrap prey and temporarily hold sperm, among other applications.

Brazilian Wandering spiders reproduce by means of eggs, which are packed into silk bundles called egg sacs. The male spider must (in most cases) make a timely departure after mating to escape before the females normal predatory instincts return.

Mature male spiders have swollen bulbs on the end of their palps for this purpose and this is a useful way to identify whether the spider is male or female. Once the sperm is inside the female spider, she stores it in a chamber and only uses it during the egg-laying process, when the eggs come into contact with the male sperm for the first time and are fertilized. The Brazilian Wandering spiders life cycle is 1 – 2 years.

Brazilian Wandering Spider Venom

Bites from the Brazilian Wandering spider may result in only a couple of painful pinpricks to full-blown envenomed. In either case, people bitten by this spider or any Ctenid should seek immediate emergency treatment as the venom is possibly life threatening.

The Phoneutria fera and Phoneutria nigriventer (two species of wandering spider) are the two most commonly implicated as the most vicious and deadly of the Phoneutria spiders.

The Phoneutria not only has a potent neurotoxin, but is reported to have one of the most excruciatingly painful envenoms of all spiders due to its high concentration of serotonin. They have the most active venom of any living spiders.

One of their members, the Brazilian Huntsman, is thought to be the most venomous spider in the world. Brazilian wandering spiders are certainly dangerous and bite more people than any other spiders.

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About joanne spencer.

I've always been passionate about animals which led me to a career in training and behaviour. As an animal professional I'm committed to improving relationships between people and animals to bring them more happiness.

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Facts About Animals

Brazilian Wandering Spider Facts

Brazilian wandering spider profile.

There are more than 50,000 species of spider, and the vast majority are less dangerous than a honeybee. Almost none are aggressive, and of those with medically significant venom, only a small percentage are capable of causing death. So, on the whole, arachnophobes are just being a bit silly.

But there’s one spider that vindicates all of these fears, and few animals are as globally renowned to be a serious threat to human lives as the Brazilian Wandering Spider .

Brazilian Wandering Spiders are actually 9 species of spider in the same genus ‘Phoneutria’, one of which is found in Central America, with the rest in South America.

Brazilian Wandering Spider Facts Overview

These spiders are called wandering spiders because of instead of spinning a web to wait for food, or occupying a lair, they spend their night wandering in the leaf litter of the jungle floor for prey.

The sensitive hairs on its body help detect vibrations of passing prey, and it will feed on insects, lizards, frogs and any animals as large as itself.

During the day they will hide under logs, rocks, or inside termite mounds and banana plants. They will also sometimes wander into urban areas and homes, where they can come into contact with humans.

Brazilian wandering spiders are aggressive , dangerous and frightening. For once, this is an animal you should be wary of.

The females are larger, around 50% heavier than males, and produce more venom, and this might be a clue as to why their Greek name translates to “ Mudress” . These spiders will often stand and fight and have an intimidating threat display.

The potency of their venom is one of the reasons they’re so dangerous, and their ability to hide away in fruit and shoes explains why most bites are on extremities.

Interesting Brazilian Wandering Spider Facts

1. armed spiders.

In Brazilian, these are sometimes known as armed spiders, on account of their elongated front legs.

They can convey quite a bit of information with these legs, and as wandering spiders, use them to get about the forest, looking for food.

2. Banana Spiders

They’re also sometimes called ‘banana spiders’ on account of their status as a stowaway on popular fruit imported from the tropics.

This is becoming less common as stricter regulations ensure there’s less contamination of fruits, but there’s always a chance your next bunch of bananas will have a family of these spiders living inside it.

3. They have the largest venom glands of any spider

Females produce more venom than males, but both sexes have enormous venom glands. These glands are even more impressive when you consider the size of the spider is significantly less than the largest around.

The venom glands of the Brazilian Wandering Spider are over a centimetre long, and this is all housed inside the bright red chelicerae (mouth parts) which they are quick to display whenever they get upset. 1

4. They’re aggressive

These spiders can grow quite large and have long, brightly-coloured legs. Unlike most spiders, they’re known to stand their ground when threatened and are far quicker to bite than many other species.

They’ll still try to scurry away where possible, and they’re not out to get anybody.

But where most other species will flee, the wandering spiders’ aggression does make it more likely to be involved in incidents.

Most bites are on fingers and toes, a sign that they’re being stepped on or grabbed inadvertently. When the spider feels cornered, it’ll rear up on its back legs and waves its colourful arms around as a warning.

Then it’ll sway side to side, beckoning you to have a go. Anything foolhardy enough to call this bluff gets a wealth of envenomation effects. 2 3

5. They give some men erections

There are ways to accomplish this with fewer side effects, but a bit from a Brazilian wandering spider does come with a certain Viagral quality.

This isn’t as fun as it might sound. Prolonged erections in this manner are likely to harm and destroy muscles and blood vessels in the penis and could cause irreparable damage.

Besides this, the assault on the central nervous system that comes with envenomation by this spider doesn’t sound worth it. 4

6. And some people die

This assault brings with it a whole host of unpleasant symptoms. Seizures, foaming at the mouth, inability to speak, collapse, and a host of other miserable experiences.

Paralysis is possible, as is cardiac shock. Blood vessels can burst in the brain, or anywhere else, and in many cases, this can be enough to kill a person.

This spider has one of the most potent venoms of all, and there are multiple legitimate records of death as a result of bites.

7. But they’re rarely fatal

While the Brazilian wandering spider is potentially one of the most dangerous spiders in the world, there is some evidence to suggest it gives a dry bite, defensively.

This means that despite exceptionally toxic venom, the amount actually injected is less than some of the other contenders, and this is what makes it typically less lethal than the Australian funnel webs.

These spiders are classified as Dangerous Wild Animals and would therefore require a special permit to keep. Bites from wandering spiders are common in South America, but antivenom is often readily available, and they rarely result in death.

In most cases, lethal bites are cases of a very young or very old victim, and few people of healthy age are killed. 5

8. They do invade the UK sometimes

These unquestionably scary spiders show up in supermarkets in the UK on occasion, having hitched a ride on banana shipments.

On more than one occasion they’ve made their way into shoppers’ homes, but it doesn’t appear that there are any cases of them biting people as a result.

These spiders aren’t suited for temperate climates and don’t survive Winter, so there’s no risk of them multiplying.

Brazilian Wandering Spider Fact-File Summary

Scientific classification, fact sources & references.

• PeerJ. (2017), “ Dimensions of venom gland of largest venom glands in all spiders ”, Bio Numbers.
• Dave Clarke (2010), “ Venomous spider found in Waitrose shopping ‘beautiful but aggressive’” , The Guardian.
• “ Phoneutria Perty (Arachnida: Araneae: Ctenidae) ”, UF-IFAS University of Florida
• Kátia R.M. Leite (2012), “ Phoneutria nigriventer spider toxin Tx2-6 causes priapism and death: A histopathological investigation in mice ”, Science Direct.
• “ Brazilian wandering spiders: Bites & other facts ”, Live Science.

AnimalBehaviorCorner

Brazilian Wandering Spider

Brazilian Wandering Spider , scientifically known as Phoneutria, emerges as a captivating enigma in the realm of arachnids.

Renowned for its formidable reputation as one of the world’s most venomous spiders , Phoneutria embodies a plethora of intriguing traits that have captured the curiosity of enthusiasts and researchers alike.

From its distinctive appearance and neurotoxic venom to its nomadic hunting strategies and unique mating behaviors , this remarkable spider species holds a wealth of fascinating secrets waiting to be unraveled.

Join us as we embark on a journey to explore the captivating world of the Brazilian Wandering Spider, shedding light on its captivating characteristics and dispelling myths that have shrouded its true nature.

1. Taxonomy and Distribution of the Brazilian Wandering Spider

A. scientific classification of phoneutria.

The Brazilian Wandering Spider, scientifically referred to as Phoneutria, occupies a distinct place within the arachnid taxonomy.

Belonging to the family Ctenidae, this spider genus is further categorized into several species, each boasting unique traits and behaviors .

Phoneutria’s taxonomic position not only distinguishes it from its arachnid counterparts but also underscores its intriguing evolutionary journey.

B. Native Habitat in South and Central America

Endemic to the lush landscapes of South and Central America, the Brazilian Wandering Spider finds its natural haven within these diverse regions.

From the rainforests of the Amazon to the tropical stretches of the Caribbean, Phoneutria has adapted to a range of environments over the course of its evolution.

The spider’s ancestral ties to these regions are tightly woven into their behaviors , anatomy, and survival strategies.

C. Preference for Tropical Rainforests and Urban Areas

Within its native territories, the Brazilian Wandering Spider exhibits remarkable versatility in its chosen habitats.

While it thrives amidst the vibrant biodiversity of tropical rainforests, it has also displayed a propensity for urban locales.

Phoneutria’s adaptability has led it to establish a presence in urban areas, where it often finds shelter in crevices, gardens, and even human dwellings.

This adaptability to both wild and urban spaces further showcases the spider’s resilience and capacity to thrive in varying conditions.

2. Physical Characteristics of the Brazilian Wandering Spider

A. size, coloration, and distinctive markings.

The Brazilian Wandering Spider , a creature of remarkable visual intrigue, boasts an array of captivating physical attributes.

Ranging in size from a few centimeters to several inches, Phoneutria showcases a size diversity that reflects the breadth of its genus.

Its coloration varies across species, encompassing shades of brown, black, and gray, often accompanied by intricate patterns and markings that adorn its exoskeleton.

These unique markings serve not only as a visual spectacle but also as essential components of its survival toolkit.

B. Camouflage and Defense Mechanisms

The Brazilian Wandering Spider’s appearance is a masterpiece of evolution, meticulously crafted to ensure both survival and predation .

Its coloration and markings are tailor-made for blending seamlessly into its surroundings, granting it a potent advantage in ambushing prey and evading predators . Moreover, these markings also play a role in its defense mechanisms.

When threatened, Phoneutria adopts a defensive posture, raising its front legs and revealing its striking markings, a visual warning to potential threats. This dual-purpose camouflage and defense strategy exemplify nature’s ingenuity at its finest.

C. Sexual Dimorphism: Unveiling Gender Differences

A fascinating facet of the Brazilian Wandering Spider lies in the realm of sexual dimorphism , where gender-based variations manifest in pronounced ways.

Females tend to be larger and more robust than their male counterparts, showcasing a size disparity that has evolved in tandem with their roles in reproduction and hunting .

Beyond size, other characteristics, such as leg structure and coloration, also exhibit subtle differences between male and female Phoneutria specimens.

This divergence in physical traits adds depth to our understanding of the species’ intricate biology and behavior .

In exploring the physical characteristics of the Brazilian Wandering Spider , we uncover a canvas painted with size diversity, intricate coloration, and unique markings.

These features, finely tuned by evolution, contribute to its prowess in camouflage and defense, while the fascinating interplay of sexual dimorphism further enriches our perception of this captivating arachnid species .

3. Venomous Nature of the Brazilian Wandering Spider

A. potent neurotoxic venom: a silent lethal weapon.

The Brazilian Wandering Spider, known scientifically as Phoneutria, harbors a venomous arsenal that stands as a testament to nature’s intricate design.

This spider’s venom contains a potent concoction of neurotoxic compounds, tailored by evolution to incapacitate its prey swiftly and efficiently.

The neurotoxins interfere with nerve cell communication, leading to paralysis and ensuring that Phoneutria’s quarry is rendered immobile and defenseless, setting the stage for a successful meal.

B. Effects on Prey and Human Hazard

When a victim succumbs to the Brazilian Wandering Spider’s venom , the effects are a symphony of paralysis and predation .

The venom’s impact on the prey’s nervous system results in swift immobilization, offering the spider a decisive advantage in subduing its catch.

While this venomous efficiency is well-adapted for predation, it also underscores the potential danger to humans.

A bite from Phoneutria can lead to a series of neurotoxic reactions, with varying degrees of severity depending on factors such as the individual’s age and overall health.

While human envenomations are relatively rare, they can result in a range of symptoms, from localized pain and swelling to more severe neurological effects.

C. Recorded Cases of Envenomations: Unraveling the Symptoms

Throughout history, documented cases of Phoneutria envenomations have offered insights into the spider’s potential threat to humans .

Symptoms typically include intense pain at the bite site, accompanied by swelling and redness . In some instances, victims have reported systemic reactions, such as muscle cramps, elevated heart rate, and even breathing difficulties.

Swift medical attention and the administration of antivenom have proven effective in mitigating the severity of these symptoms.

These cases serve as a reminder of the delicate balance between the Brazilian Wandering Spider’s potent venom and the potential risks it poses to those who unwittingly encounter it.

4. Hunting and Diet of the Brazilian Wandering Spider

A. hunting techniques and wandering behavior.

The Brazilian Wandering Spider, scientifically known as Phoneutria, unveils a mesmerizing repertoire of hunting techniques that set it apart as a master predator .

Displaying an agile and nomadic behavior , Phoneutria does not confine itself to the confines of a web. Instead, it actively prowls its surroundings, tirelessly searching for potential prey.

This dynamic wandering behavior ensures that its chances of encountering a variety of food sources are maximized, showcasing a strategic approach to sustenance.

B. Active Hunting Triumphs Over Web-Building

Unlike its web-weaving counterparts, the Brazilian Wandering Spider relies on a more hands-on approach to securing its next meal.

While weaving webs might seem an efficient method, Phoneutria’s active hunting strategy offers a distinct advantage in versatility.

By forgoing the constraints of a stationary web, it can tailor its approach to suit different environments and prey types, adapting its tactics on the fly.

This adaptability demonstrates the spider’s remarkable ability to adjust its methods for optimal results.

C. Diverse Prey Spectrum: Insects to Small Vertebrates

Phoneutria’s diet is a testament to its prowess as an opportunistic predator . Its menu spans a diverse range of creatures, from insects like crickets and cockroaches to small vertebrates such as lizards and frogs , and even small rodents.

This wide-ranging palate highlights its ecological significance in controlling various populations within its habitat.

By consuming creatures both large and small, Phoneutria ensures a balanced ecosystem, playing a crucial role in maintaining biodiversity and ecological equilibrium.

5. Mating and Reproduction of the Brazilian Wandering Spider

A. courtship rituals and behaviors: a complex affair.

The Brazilian Wandering Spider, scientifically referred to as Phoneutria, reveals a captivating array of courtship rituals and behaviors that form the cornerstone of its reproductive cycle.

Courtship among these arachnids is a complex affair, involving intricate dances and displays that serve as both communication and assessment.

Male Phoneutria employs a combination of visual cues, vibrations, and tactile interactions to court potential mates.

This elaborate courtship process highlights the significance of precise communication in the delicate dance of reproduction .

B. Cannibalistic Tendencies: A Post-Mating Phenomenon

An aspect that sets Phoneutria’s mating process apart is the notorious cannibalistic tendency exhibited by females after mating.

Following successful mating, females may exhibit an inclination to consume their partners. This seemingly counterintuitive behavior has evolutionary underpinnings.

It is believed that this cannibalistic act not only provides the female with a much-needed nutritional boost but also eliminates potential competitors and safeguards the male’s investment in the next generation.

This intriguing behavior sheds light on the complexities of reproductive strategies within the species.

C. The Unique Mating Plug Phenomenon: A Puzzling Enigma

A distinctive feature in Phoneutria’s reproductive saga is the enigmatic mating plug phenomenon. After mating, male Phoneutria deposit a specialized substance that forms a plug within the female’s reproductive tract.

This plug is believed to serve multiple purposes. It may prevent other males from mating with the female, thus ensuring the successful transmission of the mating male’s genetic material.

Additionally, it might aid in sealing off the female’s reproductive tract, potentially protecting her from external pathogens.

This phenomenon underscores the intricate interplay of biological strategies that contribute to the species’ reproductive success.

6. Human Interaction and Urban Legends of the Brazilian Wandering Spider

A. occasional presence in urban areas: nature in our midst.

The Brazilian Wandering Spider, scientifically known as Phoneutria, has carved a niche for itself not only in the wild but also in the fabric of urban environments.

While its primary habitats are the lush landscapes of South and Central America, Phoneutria occasionally ventures into human -inhabited spaces. Its adaptability allows it to find shelter in gardens, crevices, and even within homes.

This coexistence with humans adds an intriguing dimension to our encounters with this enigmatic arachnid .

B. Debunking Misconceptions: Separating Fact from Fiction

The presence of the Brazilian Wandering Spider has sparked a plethora of misconceptions and exaggerated tales, contributing to the creation of urban legends.

Stories of spiders leaping from banana bunches or hiding under toilet seats have become part of modern folklore, often fueled by sensationalism.

It’s crucial to sift through these tales and recognize that while Phoneutria’s venom is potent, the likelihood of encountering a dangerous encounter is relatively low.

Separating fact from fiction empowers individuals to approach these creatures with accurate knowledge.

C. Importance of Proper Education: Identifying Friend from Foe

Education plays a pivotal role in fostering a harmonious coexistence between humans and the Brazilian Wandering Spider .

Learning to identify and understand the behaviors of Phoneutria species enhances safety for both humans and the spiders themselves.

Instead of succumbing to unwarranted fear, individuals can take steps to reduce the chances of accidental encounters and, if necessary, engage in responsible removal methods.

By arming themselves with knowledge, individuals can navigate encounters with urban-dwelling Phoneutria specimens with confidence and respect.

7. Brazilian Wandering Spider Conservation and Misunderstanding

A. significance of phoneutria in ecosystem dynamics.

The Brazilian Wandering Spider , scientifically termed Phoneutria, assumes a pivotal role within its ecosystem, contributing to a delicate balance of populations and interactions.

As a top-tier predator , it plays a crucial part in controlling insect and small vertebrate populations, preventing unchecked growth that could disrupt the ecosystem’s equilibrium.

By maintaining these population dynamics, Phoneutria ensures the health and stability of its habitat, highlighting its significance beyond its ominous reputation.

B. Impact of Fear and Misunderstanding: Hindrances to Conservation

Despite its ecological contributions, the Brazilian Wandering Spider often falls victim to fear-driven misconceptions that negatively impact conservation efforts.

Misunderstandings surrounding its behavior and potential danger can lead to unwarranted extermination campaigns and habitat destruction.

Fear-driven reactions not only disrupt the natural balance but also hinder opportunities to study and appreciate the species for its ecological significance.

Addressing these misconceptions is crucial to ensuring the spider’s survival and maintaining the health of its ecosystems.

C. Efforts to Dispel Myths and Promote Coexistence

Efforts to conserve the Brazilian Wandering Spider are interwoven with endeavors to educate and dispel myths.

By providing accurate information and dispelling exaggerated tales, conservationists aim to reshape public perception.

Collaborative initiatives emphasize coexistence, highlighting the importance of responsible behavior when encountering Phoneutria.

Educating communities about the spider’s role, behavior, and conservation status fosters an environment where fear gives way to appreciation, and where balanced cohabitation becomes a reality.

8. Research and Medical Significance of the Brazilian Wandering Spider

A. ongoing scientific research on phoneutria venom.

The Brazilian Wandering Spider , Phoneutria, has garnered significant attention from the scientific community due to the unique properties of its venom.

Ongoing research delves into the intricate composition of the venom, aiming to unlock its mysteries and potential applications in various fields.

The diverse array of compounds within the venom, particularly its neurotoxic components, has attracted interest for their potential medical and therapeutic implications.

B. Antivenom Development and Therapeutic Prospects

One of the most promising areas of research surrounding Phoneutria lies in the development of antivenoms and therapeutic agents.

The venom’s potent neurotoxic effects on the nervous system have spurred efforts to create targeted treatments for conditions such as chronic pain and neurological disorders .

Additionally, the potential for antivenoms holds promise in mitigating the effects of envenomations, offering a lifeline for individuals who encounter these spiders .

This focus on harnessing the venom’s properties for positive medical outcomes highlights the transformative potential within this enigmatic arachnid .

C. Balanced Perspectives: Navigating Ethical and Scientific Endeavors

While research on the Brazilian Wandering Spider’s venom offers tremendous potential, it necessitates a balanced perspective.

As researchers probe the venom’s properties, ethical considerations arise, including the well-being of the spiders and their ecosystems.

A holistic approach acknowledges the value of understanding Phoneutria’s natural behaviors and conserving its habitats.

This balanced perspective extends to utilizing the venom’s potential responsibly, ensuring that breakthroughs are achieved while respecting the complex interplay of science and nature.

9. Frequently Asked Questions about the Brazilian Wandering Spider

What is the brazilian wandering spider.

The Brazilian Wandering Spider , scientifically known as Phoneutria, is a venomous arachnid found in South and Central America. It’s notorious for its potent venom and is considered one of the most venomous spiders in the world.

Is the Brazilian Wandering Spider dangerous to humans?

Yes, the Brazilian Wandering Spider’s venom contains potent neurotoxins that can cause a range of symptoms in humans , from localized pain and swelling to more severe reactions. While bites are relatively rare, it’s advisable to exercise caution when encountering these spiders.

What is the spider’s habitat?

The Brazilian Wandering Spider is native to tropical rainforests of South and Central America. However, it’s adaptable and can also be found in urban areas, such as gardens and houses.

How does the Brazilian Wandering Spider hunt?

Unlike many spiders that build webs, Phoneutria is an active hunter. It roams its environment in search of prey, relying on its keen senses to detect vibrations and movements.

Are Brazilian Wandering Spiders aggressive toward humans?

Brazilian Wandering Spiders are not naturally aggressive towards humans and will typically only bite in self-defense. However, caution is advised, especially in areas where these spiders are known to inhabit.

Can the Brazilian Wandering Spider’s venom be used for medical purposes?

Yes, research is ongoing into the potential medical applications of Phoneutria’s venom. Its neurotoxic properties have sparked interest in pain management and neurological treatments.

Is the spider’s reputation for crawling into banana shipments true?

While there have been stories of Brazilian Wandering Spiders being found in shipments of bananas, these occurrences are extremely rare. Spiders are unlikely to survive the conditions of shipping and storage.

How can I stay safe around Brazilian Wandering Spiders?

To stay safe, it’s important to be cautious when encountering spiders in their natural habitat. Avoid provoking or handling them, especially if you’re unsure of their identity. If you suspect you’ve been bitten, seek medical attention promptly.

Are there any efforts to conserve the Brazilian Wandering Spider?

Conservation efforts for the Brazilian Wandering Spider are intertwined with public education and dispelling myths. Recognizing its role in ecosystems and promoting coexistence are essential steps in preserving this unique species.

What can I do if I find a Brazilian Wandering Spider in my home?

If you encounter a Brazilian Wandering Spider in your home, it’s advisable to contact local pest control professionals who can safely remove the spider without causing harm.

In the intricate tapestry of nature, the Brazilian Wandering Spider , Phoneutria, emerges as a creature of both fascination and caution.

Its venomous nature and captivating behaviors have earned it a place among the most enigmatic arachnids .

As we continue to explore its world, debunk myths, and understand its vital role in ecosystems, we find a delicate balance between awe and respect.

Armed with knowledge, we navigate the realm of Phoneutria, appreciating its complexity while fostering coexistence, a testament to the intricate dance between humans and the natural world.

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Brazilian Wandering Spider: Care, Food, Habitat & Preventions

Mike Wallace

Have you ever heard of or do you know what a  Brazilian wandering spider is ? It is a big venomous spider from places like Central and South America, and people sometimes call it the  banana spider . Why? Well, we are about to find out!

Table of Contents

These wandering spiders are aggressive hunters who go out on the hunt at night. Their meals include both invertebrates (like insects) and vertebrates (creatures with a backbone, like small animals).

These spiders are super dangerous because their venom is like a powerful potion that can make people really sick or even worse. They usually hang out in tropical rainforests and even in cities, hiding in banana plants. 

So, let’s get more information about the world of this sneaky spider to learn the details about its looks, eating habits, where it lives, the venom it carries, and find out if it is genuinely risky. Ready to explore? Keep reading!

Brazilian Wandering Spider Description:

Scientific name and family:.

In Brazil, they are sometimes known as “ armed spiders ” (armadeiras), and they share the name “ banana spiders ” with a few other spiders. They have different names, but they are all talking about the same interesting spider!

The Brazilian wandering spider, scientifically known as  Phoneutria , Maximilian Perty kickstarted the Phoneutria genus in 1833. The name comes from the Greek word φονεύτρια , which means “murderess” and falls under the Animalia kingdom, Arthropoda phylum, and Arachnida class.

Within Arachnida, it is classified in the order Araneae, infraorder Araneomorphae, and Ctenidae family. The genus Phoneutria, described by Perty in 1833, includes the type species  Phoneutria fera .

This classification helps us understand where these spiders fit into the larger picture of living organisms.

The following 9 species are accepted by The  World Spider Catalog :

• Phoneutria bahiensis
• Phoneutria boliviensis
• Phoneutria eickstedtae
• Phoneutria fera
• Phoneutria keyserlingi
• Phoneutria nigriventer
• Phoneutria pertyi
• Phoneutria reidyi
• Phoneutria depilata

What do Brazilian Wandering Spider look like?

Size range:.

The spiders in the Phoneutria group can get pretty big in size. Their legs can stretch out to be 13 to 18 centimeters (5 to 7 inches) wide, and their bodies can have a range between 17 to 48 millimeters (a little more than half an inch to almost 2 inches) long.

The female Brazilian spiders can get pretty big, reaching up to 15 centimeters (5.9 inches) in length. On the other hand, the males are smaller, usually measuring around 7 centimeters (2.8 inches). They usually weigh up to 0.21 ounces.

They have long, slender legs, and even though some other spiders with different names might have longer legs, the Phoneutria spiders are champions when it comes to having the longest bodies and being the heaviest in their spider gang.

The spider’s body has two main parts. The first is the prosoma, kind of like its “head,” where you will find all eight legs, eyes, fangs (chelicera), and little multitasking arms (pedipalps).

The second part is the opisthosoma, holding the spinnerets for making silk, the back end opening (anal opening), “the lungs,” the heart, and the important bits for making baby spiders (reproductive organs).

So, the prosoma is like the front control center, and the opisthosoma is like the back office, handling things like silk-making and baby-making.

Brazilian spiders come in different colors, with most being hairy and shades of brown and gray. Some species may have lightly colored spots on their abdomen.

A distinctive feature of many species is the presence of bands of black and yellow or white on the underside of their two front legs.

Identification:

To identify a spider from the Phoneutria group, look for a dense brush of fine hairs on their leg parts. They might seem like other spiders, especially  Cupiennius , but here is how you can differentiate: 

• Phoneutria often have a dark line on the front of their palps and a thin black line on top of their head. 
• Check underneath, too; their legs usually have dark parts and light joints. Sometimes, the belly has black dots or is reddish. 
• Usually it has been observed that when they are upset, they do a cool defensive move like lifting their front legs high with a distinctive pattern. So, if you see a spider doing that dance, it is probably a Phoneutria!

Brazilian Wandering Spiders live all over the Americas, from Costa Rica to northern Argentina. They are like the residents of the jungle, chilling in forests east of the Andes in countries like Colombia, Venezuela, Ecuador, Peru, Bolivia, Brazil, Paraguay, and the Guianas.

Some, like P. reidyi, P. boliviensis, and P. fera, love the Amazon rainforest, while others prefer the Atlantic Forest in Argentina, Paraguay, and Brazil.

They have also made themselves at home in the Cerrado savanna. But if you head to northeastern Brazil, they are not around. These spiders have even taken trips to Chile and Uruguay.

Why are they called Banana Spiders?

These spiders are linked with bananas. Richard S. Vetter, a researcher at the University of California, found that these powerful spiders sometimes end up in North America and Europe by accident, hitching a ride in banana shipments.

But it is often a case of mistaken identity. Only a few Phoneutria species have been found in banana shipments, and sometimes, other spiders get the blame due to misidentification. 

What They Like to Eat or Hunt?

Their food includes flies, beetles, butterflies, moths, grasshoppers, locusts, and crickets. Occasionally, they might even feast on small creatures like amphibians, reptiles, or mice. All these diet or food findings tell us about how diversified eating habits these fascinating spiders have.

Mating and Lifecycle:

Like most spiders, the female spiders are bigger than the males. When the male spider wants to be friends, they do a little dance (vibrating his pedipalps and specialized sensory appendages) to signal his intentions to impress the female, but it is a cautious approach.

The behavior of the female can be choosy, and she might say no to a few before picking the right one. 

After the dance, sometimes, the females decide to attack them, or if she is interested, she can store the male’s baby-making material in a special place until she is ready to use it.

Then, she lays a bunch of eggs, up to 1,000 at a time, and keeps them safe in a silk egg sac. Sadly, after laying her eggs, the mom spider says goodbye. It is her way of making sure the new spiders are ready to explore the world on their own.

The lifespan of the banana spider (Phoneutria nigriventer) differs for males and females. Females usually live for 6 to 8 weeks after reaching maturity, while males have a shorter lifespan of 2 to 3 weeks after their last molt. 

Certain mammals, like coatis (Procyonidae, which includes raccoons) and other small insectivores, birds are potential predators of large wandering spiders.

These spiders got their name as wandering spiders because of the fact that they are not into web building. Instead, they stroll around the forest floor at night(nocturnal), searching for dinner.

Brazilian Wandering Spiders are active hunters and use both ambush tactics and direct attacks to catch their prey. During the day, they prefer cozy spots like under logs or in crevices, only emerging at night for their hunting adventures. These spiders do not build nests like other spider species.

While wandering spiders are not naturally aggressive towards humans, they won’t hesitate to bite if they feel cornered or threatened. Most bites happen when a spider accidentally gets trapped in clothing or bedding. 

Bite and Venom:

The bite of the armed spider is the most dangerous in the world as the venom it carries can be harmful to humans.

The danger is not just about how strong the venom is; it is also about factors like the spider’s likelihood to bite and how close it is to where people live.

These spiders often hide in houses, clothes, and other dark places during the day, making accidental bites more likely. 

While their fangs are adapted for small prey, some experts think they might give a “dry” bite in defense to save venom. Studies suggest that not all bites inject venom, and serious cases requiring antivenom are rare.

However, there have been confirmed cases of death, with symptoms appearing quickly, including:

• Severe pain
• Breathing difficulties
• Increased heart rate and blood pressure
• In severe cases, paralysis and death

The severity can depend on the spider’s sex, with females generally more dangerous. The spiders produce less venom in colder months, and a small amount can be potent enough to harm.

Fortunately, bites from Brazilian spiders are rare, and when they do occur, the exposure to the toxins is generally mild, as explained by Vetter.

Also Read: What is a Huntsman Spider? (Heteropodidae) – The Ultimate Guide

Banana Spider’s Facts:

Below are essential details about Brazilian wandering spiders:

• They hold the title for the world’s largest spiders , boasting leg spans reaching up to 15 centimeters (6 inches).
• Their venom packs a powerful punch, capable of inducing severe pain, paralysis, and, in extreme cases, fatal outcomes for humans.
• Despite their intimidating reputation, they are generally non-aggressive and resort to biting only when provoked.
• These spiders inhabit tropical rainforests and urban areas across Central and South America.
• In case someone has been bitten by this spider, he/she needs quick medical treatment to control the effects timely.

Treatment and Preventive Measures:

If bitten by a wandering spider or armed spiders, prompt medical attention is crucial. There is an antivenom for the spider’s venom, but its effectiveness is highest when administered within a few hours of the bite.

To prevent a bite:

• Wear protective clothing, use shoes and long pants when in areas where these spiders are found.
• Before wearing your clothes and shoes, make sure to check them to ensure no spiders are hiding.
• Maintain cleanliness and avoid leaving food or garbage exposed, as this can attract spiders.

These preventive measures are essential for minimizing the risk of encountering and getting bitten by Banana spiders.

Can Brazilian spiders kill humans?

Brazilian wandering spiders (Phoneutria nigriventer) are venomous and can potentially kill a human with a single bite. Their venom contains a potent neurotoxin that can cause severe pain, paralysis, and even death. 

Are Brazilian spiders poisonous?

Yes the venom of this spider is poisonous, that can cause death. While Brazilian wandering spiders are potentially dangerous, actual bites are relatively rare.

By adopting preventive measures and promptly seeking medical attention if bitten, the risk of serious complications can be significantly reduced.

Can you keep Brazilian spiders as pets?

It is strongly advised against keeping wandering spiders as pets due to their venomous nature and the potential risk to human safety.

Managing these spiders in captivity demands specialized knowledge and handling procedures to minimize the risk of bites.

Final Thoughts:

The Brazilian wandering spider, banana spider, or armed spider is a large and venomous arachnid found in Central and South America. While their potent venom can be harmful to humans, encounters are rare.

These nocturnal hunters have adopted various habitats, from rainforests to urban areas, and are associated with banana shipments. Understanding their appearance, behavior, and habitat is crucial for minimizing risks.

Seeking immediate medical attention after a bite is essential, as antivenom is available but most effective when administered promptly. Despite their fearsome reputation, the Brazilian spider remains a captivating and potentially dangerous species.

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Southeastern Wandering (Anahita punctulata)

Have you ever heard of Southeastern wandering spiders ? They’re part of the big Ctenidae family and come from the Anahita group. These spiders can be found in various places in America.

Scientific Classification

• Family: Ctenidae
• Genus: Anahita

Physical Description and Identification

• Size: They are between 0.20 inches and 1.56 inches in length, with females larger than males.
• Color: These spiders have a brown or tan body.
• Other Characteristic Features: They have long legs like most other wandering spider species.

The eggs are small and round enclosed safely inside a silken sac.

Spiderlings

Though sufficient details remain unavailable, they stay with their kin until maturation and then disperse to be on their own.

Like other wandering spiders, this species too does not spin webs but attacks their prey by suddenly attacking them from their hidden den.

Are Southeastern Wandering Spiders Venomous?

Yes, Southeastern wandering spiders do have venom. It helps them catch and eat their food. But for most people, it’s not super dangerous.

Can Southeastern Wandering Spiders Bite?

Sure can! Like many spiders, they might bite if they get scared. It can be a bit painful, but usually, it’s okay. Best to be gentle with them!

Photo Credit: Kathy Hardy

Ecological Importance and Behavior of Southeastern Wandering Spider

Southeastern wandering spiders play an essential role in maintaining the balance of their ecosystems. By preying on small insects, they help control the population of potential pests, contributing to a healthier environment. Their nomadic nature and ambush-hunting tactics showcase their adaptability and resilience, making them fascinating subjects for arachnological studies.

Natural Predators and Prey-Predator Dynamics: In the wild, these spiders face threats from birds, larger spiders, and other predators. The sophisticated dance between predator and prey is a vital aspect of their existence, influencing their behavior, life cycle, and the broader ecological balance.

Relationship with Humans: While encounters with humans are infrequent, it’s crucial to foster a respectful and informed relationship with these spiders. Understanding their role in the ecosystem and acknowledging their generally non-threatening nature helps in demystifying these creatures, paving the way for coexistence and appreciation.

Quick Facts

Did you know.

• Like most other species of their family, the Southeastern spider also bears a close resemblance to the wolf spiders .

In summary, the Southeastern wandering spiders are a remarkable testament to the adaptability and resilience of arachnids.

Other Spiders in this Family

Wandering spiders.

Phoneutria depilata

Phoneutria boliviensis

Phoneutria fera

Phoneutria nigriventer

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How to Identify a Brazilian Wandering Spider

Last Updated: February 12, 2021 Approved

This article was co-authored by wikiHow Staff . Our trained team of editors and researchers validate articles for accuracy and comprehensiveness. wikiHow's Content Management Team carefully monitors the work from our editorial staff to ensure that each article is backed by trusted research and meets our high quality standards. There are 8 references cited in this article, which can be found at the bottom of the page. wikiHow marks an article as reader-approved once it receives enough positive feedback. In this case, 93% of readers who voted found the article helpful, earning it our reader-approved status. This article has been viewed 133,493 times.

The Brazilian wandering spider is a large, hairy spider that lives in South and Central America. It’s considered the most venomous spider in the world. Since these spiders sometimes wander right into towns, cities, and shipments of fruit, it’s important to be able to recognize this spider and know its habitat. If you happen to be bitten, you should get immediate medical attention. Don’t panic, however! These bites can almost always be treated.

Recognizing a Brazilian Wandering Spider

• Some spiders may be more yellowish than brown. Others may appear to have black legs, or black bands on brown legs. [3] X Research source

• Do not try to trap this spider. Call animal control professionals if you think you have one in your home or outdoor buildings, and leave those buildings while you wait for help.

Being Aware of Their Habitats

• Small, unlit closets or nooks in homes
• Outdoor sheds and garages
• Unused clothes, shoes, or gloves
• Boxes of food in pantries
• Boxes in attics or garages

Avoiding a Bite

• If a spider falls out, don’t panic. Back away slowly and leave the area.

• You can also spray bug and spider repellant around doors and windows to ward off creepy crawlies.

Treating a Bite

• In men, these bites can also cause a long and painful erection.

Community Q&A

• Keep in mind that these spiders prefer to wander along the ground. Always wear sturdy shoes if you are in an area where these spiders are known to live. Thanks Helpful 1 Not Helpful 0
• These spiders are highly dangerous and should not be approached or provoked unless you are an expert such as an entomologist. They are recognized as one of the most dangerous spiders in the world and are the most venomous so they should always be treated with care and respect. Thanks Helpful 1 Not Helpful 0
• Children are more susceptible than adults to the venom of a Brazilian wandering spider, and you should ensure that any child who’s bitten gets medical attention as quickly as possible. Thanks Helpful 5 Not Helpful 0

You Might Also Like

• ↑ https://www.livescience.com/41591-brazilian-wandering-spiders.html
• ↑ http://www.wandering-spiders.net/phoneutria/gallery/
• ↑ https://animalcorner.co.uk/animals/brazilian-wandering-spider/
• ↑ http://bioweb.uwlax.edu/bio203/s2013/johnson_jor4/habitat.htm
• ↑ http://www.mayoclinic.org/diseases-conditions/spider-bites/manage/ptc-20204189
• ↑ https://www.livescience.com/37974-he-surprising-cause-of-most-spider-bites.html
• ↑ http://www.mayoclinic.org/first-aid/first-aid-spider-bites/basics/art-20056618
• ↑ http://www.webmd.com/first-aid/snakebite-treatment

About this article

To identify a Brazilian wandering spider, look for a spider with a long leg span of about 6 inches and a brown, hairy body. Also, carefully examine the spider from afar to see if it has large red fangs, which are common in Brazilian wandering spiders. Keep in mind that Brazilian wandering spiders only live in South and Central America. If you encounter one, move away slowly since Brazilian wandering spiders are aggressive and very poisonous. To learn how to avoid getting bitten by a Brazilian wandering spider, scroll down! Did this summary help you? Yes No

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Brazilian Wandering Spider size: how big do they get?

As an avid arachnid enthusiast, my fascination with these eight-legged creatures knows no bounds. There’s something utterly captivating about their intricate web-weaving capabilities, their exceptional survival strategies, and of course, their range of sizes and appearances. But amongst this vast collection of species, one has particularly piqued my interest – the Brazilian Wandering Spider.

Arguably one of the most notorious names in the world of arachnids, the Brazilian Wandering Spider, holds a firm position at the pinnacle of spider folklore. Their reputation extends far beyond their native tropical South American rainforests, captivating the minds of arachnologists and laymen alike around the globe.

What sets this spider apart in the arachnid world? It’s not just its venomous nature – it’s also its astonishing size. The dimensions of the Brazilian Wandering Spider are a spectacle in themselves.

How big are Brazilian Wandering Spiders?

Picture this: a spider so large that it could comfortably cover an average dinner plate. That’s right – the Brazilian Wandering Spider can grow to an impressive leg span of up to 7 inches , or approximately 18 cm, with females tending to be larger than the males.

To put this into perspective, that’s around half the size of an average adult human’s face! The body length of these spiders can reach up to 2 inches, or around 5 cm. This considerable size, coupled with their highly potent venom, makes them a formidable presence in their habitats.

But as an arachnid hobbyist, the allure of the Brazilian Wandering Spider’s size lies not in its potential threat, but in the fascinating evolutionary adaptations that have allowed it to grow to such an impressive scale.

The advantage of large size for a cursorial hunter

From an evolutionary standpoint, the Brazilian Wandering Spider’s significant size offers multiple advantages. For starters, their considerable size allows them to subdue and consume a larger variety of prey, including insects, other spiders, and sometimes even small amphibians and reptiles. This dietary diversity is a testament to their adaptability and survival prowess.

However, the size of these spiders is not solely an indicator of their hunting prowess. It also reveals a fascinating aspect of their biology. The Brazilian Wandering Spider, unlike some smaller spider species, does not weave a web to capture its prey. Instead, as their name suggests, they wander in search of food, relying on their size and strength to overpower their prey. This is called cursorial hunting .

Their size also plays a crucial role in their mating rituals. Male Brazilian Wandering Spiders, despite being smaller than their female counterparts, engage in a daring dance of danger during mating. They utilize their size and strength to lift the larger female’s body to prevent her from eating him – a gruesome but prevalent behavior known as sexual cannibalism in the arachnid world.

Size relates to the biology of the Wandering Spider

The Brazilian Wandering Spider’s size, therefore, is much more than just an intimidating factor. It’s a key to understanding their hunting methods, their mating rituals, and their overall survival strategy. Each inch adds to the mystique of these extraordinary creatures and deepens our understanding of the diverse world of arachnids.

The Brazilian Wandering Spider is undeniably a creature of fascination. From its substantial size to its potent venom, it’s a spider that demands respect. Whether you’re an arachnid hobbyist like me, or just someone intrigued by the wonders of the natural world, the Brazilian Wandering Spider offers a fascinating insight into the awe-inspiring world of arachnids.

Final thoughts…

In conclusion, the world of spiders is as vast and varied as the creatures themselves. The Brazilian Wandering Spider, with its impressive size, offers a fascinating window into this world. It’s a testament to the incredible diversity of life on Earth and a reminder of the intricate balance that governs our ecosystems.

My fascination with spiders continues to grow, much like the impressive size of the Brazilian Wandering Spider. And while their size may be a source of fear for some, for me, it only fuels my passion and curiosity about these fascinating creatures. After all, understanding is the first step to appreciation, and these giant spiders deserve nothing less.

Whether you’re a fellow arachnid enthusiast or just passing by, I hope this deep-dive into the size of the Brazilian Wandering Spider has sparked your curiosity. So the next time you hear about this giant spider, remember, there’s more to its size than meets the eye!

If you’d like to learn more about these spiders, check out my article on Brazilian Wandering Spider facts .

FAQ related to Brazilian Wandering Spider Size

How bad is a brazilian wandering spider bite.

A Brazilian Wandering Spider bite is considered a medical emergency. If you have a suspected or confirmed bite, your first move should be to contact the emergency services. Upon reaching you, they will determine whether to administer antivenom, and how to proceed with treatment. Fortunately, deaths are very rare, and the antivenom is widely available in South America.

Is a banana spider the same as a Brazilian wandering spider?

The common name of “Banana Spider” is used for a few species, not just the Brazilian Wandering Spider. For example, the Golden Silk Orb Weaver is often referred to as a banana spider, despite being completely unrelated. If you wish to find out if a spider is venomous, always rely on its scientific, or binomial name, rather than common names.

Where do Brazilian wandering spiders hide?

Brazilian Wandering Spiders are nocturnal hunters, and generally prefer to shy away from daylight. This means they often hide in the shadiest places they can find, either indoors or outdoors. For example, under a log or in leaf litter would be a perfect place outdoors. Indoors, they will try to hid behind or under furniture, or in dark corners.

What is the world’s biggest Brazilian wandering spider?

There are around 40 species of Wandering Spider, but the largest, and most infamous are those that we call the Brazilian Wandering Spider. This name is in fact commonly ascribed to two species: Phoneutria nigriventer and Phoneutria fera. Both of these spiders can reach at least 6 inches (15cm) in legspan.

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Brazilian Wandering Spider Facts: What Happens If It Bites You?

Brazilian wandering spiders belong to the genus Phoneutria  and are represented by eight spider species that are native to Central America and South America. This spider group is also collectively known as armed spiders and banana spiders. In Brazil, they are locally known as "aranha armadeira" which means armed spider. With these, some people often wonder if a person can survive after being by a member or species of this group.

What is a Brazilian Wandering Spider?

The genus Phoneutria , which the Brazilian wandering spider  and related spider species belong to, was first described in 1833 when two species was included on it. The following century saw various scientists to move the Phoneutria species between genera Phoneutria  and Ctenus . In 1936, Mello-Leitao restored Phoneutria  and currently contains eight species, as reported by the University of Florida.

Banana spiders, a name given to the arachnid group due to their frequent presence on banana leaves, are large and robust arachnids in the family Ctenidae .   They resemble the morphological appearance of wolf spiders. In addition, their body length can grow ranging from 17 and 48 millimeters and their leg span can reach 180 millimeters. Their distinct color ranges from light brown, brown, or grey. Furthermore, the natural habitats of armed spiders are forests.

Also Read:   Deadly Erection-Giving Spider Crawls Out of Banana In Bristol

What Happens If It Bites You?

The natural prey of Brazilian wandering spiders includes small animals like crickets, mantids, and katydids, and larger ones like bats, frogs, and lizards. However, they can still bite humans and other animals not native in their habitats. In the past, scientists have identified that the bite of banana spiders living in Central and South American rain forests can lead to shortness of breath and excessive salivation.

According to wildlife experts, a Brazilian wandering spider bite can also lead to other serious symptoms, including increased blood pressure, above-normal pulse, and unusual respiratory rate, as well as extreme pain, hours-long penile erection, and death, in some cases. These spiders inject neurotoxin venom to its bitten victim and can be deadly to humans, particularly for children. However, it is not the world's deadliest spider.

Venomous Spider

In a study published in the journal Frontiers  in February 2023, researchers stated that the Brazilian wandering spider is amongst the world's most dangerous venomous spiders in the world. In Brazil, there have been an estimated 4,000 envenomation accidents of Phoneutria nigriventer  spider species each year in Brazil. Additional symptoms were also observed, including blurred vision, priapism, and vomiting.

The armed spider only follows the world's most venomous spider, which according to the Guinness World Records , is the Sydney funnel-web spider ( Atrax robustus ).

Like the Brazilian wandering spider, the venom of A. robustus  can be neutralized by anti-venoms but some cases still lead to deaths when these arachnids bite a human, who did not receive any medical attention. Experts also weigh that the mortality of venom depends on the amount that enters a human body.

Related Article:   Arachnophobia Nightmare: Giant Spider Found Inside Banana Box at Grocery Store in Germany

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This is one of the most dangerous spider species in the world.

Image Credit: Dr Morley Read/Shutterstock

Meet the Brazilian wandering spiders in the genus Phoneutria , also referred to as the armed spiders or the banana spiders. The members of this group have one of the most dangerous bites of any spider species on Earth and they have been classified as the world’s most venomous spider many times.

Where Do Brazilian Wandering Spiders Live?

Though currently the Guinness World Record is shared with another species – the Sydney funnel-web, ( Atrax robustus ) – the Brazilian wandering spiders are a force to be reckoned with. 

As the name suggests all the Brazilian wandering spiders can be found in northern South America, with at least one species having distributions across more than just Brazil, writes the University of Florida . However, Phoneutria fera and Phoneutria nigriventer are the main species that feature in news articles as they often travel overseas in shipments of bananas, causing panic and confusion – and even the closure of supermarkets . 

What Is The Size Of A Brazilian Wandering Spider?

The size of the Brazilian wandering spiders varies between species. Some can be very large with a leg span of 18 centimeters (7.1 inches). The spiders are famously quite aggressive, and instead of running from threats will rear up onto their back legs and stand their ground. 

What Are The Effects Of A Brazilian Wandering Spider Bite?

Brazilian wandering spiders often make the news because of the unusual symptoms caused to humans after being bitten by one. 

A 2023 study in Frontiers In Molecular Biosciences suggested there were around 4,000 cases of people being bitten by Phoneutria nigriventer in Brazil each year. Their venom affects the nervous system, causing double vision, salvation, irregular heartbeat – and even prolonged painful erections, known as priapism . In fact, because of this, their venom is being explored as a possible treatment for erectile dysfunction conditions.

Can A Brazilian Wandering Spider Bite Kill You?

The neurotoxin PhTx3 is to blame for these symptoms, and according to the Independent , a wandering spider bite can reportedly be fatal in as little as 60 minutes. However, an effective anti-venom is usually enough to save those affected. A study into Phoneutria boliviensis in 2019 suggested that the species had adapted its venom to catch vertebrates as opposed to lizards and amphibians, which might explain why the venom is so toxic to humans. 

It comes as no surprise then that their scientific name Phoneutria means “murderess” in Greek. 

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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.

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

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

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:

• Pain that radiates from the bite
• Muscle cramps
• Increased sweating

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

Comparison with Other Venomous Spiders

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

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

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, whatsthatbug.com 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

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

Letter 2 – Wandering Spider from Costa Rica

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 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 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”

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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Where to See the World’s Biggest Spiders

Don’t freak out—our arachnid friends help more than hurt

Jennifer Billock

Travel Correspondent

Currently, more than 46,000 spider species stretch their eight legs in habitats across the world, in every country and continent except Antarctica. And those are only the ones scientists have been able to find and name so far—many more are likely still out there, lurking under leaves and rocks and, for Halloween’s sake, perhaps under a bed or two.

Although some people find these creatures terrifying—a spooky symbol of haunted houses and Halloween frights—we owe a lot to our arachnid friends. Not only have they been around for about 350 million years (trumping our puny 200,000-year modern human existence), spiders make it possible for us to eat and live a more comfortable life.

“If spiders disappeared, we would face famine,” Norman Platnick, a spider expert at New York’s American Museum of Natural History, told the Washington Post in 2014 . “Spiders are primary controllers of insects. Without spiders, all of our crops would be consumed by those pests.”

For that matter, so would we. Because spiders munch on insects, they save us from bites.

“Without spiders’ existence and abundance on the planet, life on earth would probably be a less hospitable place for people because the biting flies and mosquitoes of the world would be so populous,” Cat Urban, manager of the invertebrate live animal programs at the Natural History Museum of Los Angeles County, which hosted a Spider Pavilion for visitors in 2018, told Smithsonian.com.

This year, museum-goers can face their fears further north at the Royal Ontario Museum in Toronto. Through January 6, 2019, over 400 live and preserved arachnids will be on display in the museum's Spiders: Fear & Fascination exhibition. Hands-on activities, live venom milking demonstrations, augmented reality experiences and a recreated spider cave bring visitors face-to-face with these fascinating and misunderstood creatures. The exhibit features two of the world's largest spiders, the goliath birdeater and the Brazilian wandering spider.

If you want to see these and other eight-legged giants in the wild, here are a few places to see the world's biggest:

Giant Huntsman – Heteropoda maxima (Laos)

This type of spider was discovered in Laos in 2001, hiding in a cave. Measuring by leg span, it’s the biggest in the world—the creepy crawlers can reach up to a foot wide. They’re crazy fast, can climb up smooth surfaces and walk sideways. Fortunately for arachnophobes, all huntsman spider species are as scared of us as we might be of them. They’ll run away fast once you see them, and they don’t like to bite (though they won’t kill you if they do, just cause some local swelling). The giant huntsman lives in caves in Laos and has only been seen on rare occassion. Other species of huntsman spiders, that average only about five inches in leg span, are common in Australia and Asia.

Goliath Birdeater Tarantula – Theraphosa blondi (South America)

Based on mass, this is the largest spider in the world (leg-span measurements make it second to the giant huntsman). They’re so big that in 2014, an entomologist wandering through the rainforest in Guyana found one that was as big as a puppy and weighed just as much. The name may just be a clever note on its size—it’s debated whether the spider actually eats birds. Mostly the spider dines on crickets, beetles and occasionally small mammals and frogs. In any case, it has fangs almost an inch long (although its bite is considered no worse than a wasp's sting) and is covered in tiny prickly hairs that it shoots out at whoever is bugging it. But the most distinctive thing about it is the sound it makes: it hisses. In order to shoot out the teeny hair, it has to rub its legs against its abdomen, creating a hissing sound.

The goliath birdeater can be found in the rainforests of northern South America, including Venezuela, northern Brazil, Guyana, French Guiana and Suriname, and at the Amazonia exhibit at the Smithsonian National Zoo.

Brazilian Salmon Pink Birdeater – Lasiodora parahybana (Brazil)

Just like its friend the goliath, this tarantula is really, really big. Its legs span up to 11  inches , and it grows six of those inches in just its first year of life. The spider is endemic to the Atlantic forest region of Brazil and can be seen wandering the forest floor at night. 

The spider gets its name from coloring: pink hairs stick out in patches from the mouth, abdomen and legs. Plus, they really do eat birds. Small ones. Sometimes. Otherwise, they eat bugs, lizards, frogs and mice. But before dining, they spit digestive fluid onto their prey, so it’s partially digested before they dig in.

Sri Lankan Tarantula – Poecilotheria rajaei (northern Sri Lanka)

Ever wondered what a spider as big as your face looks like? This is it. Its leg-span is about eight inches. Scientists discovered it hanging around in trees and an old hospital in Sri Lanka in 2013. The spider’s coloring is unique—it has a pinkish band around the abdomen and yellow and gray geometric patterns on its legs. The name is unique as well; it was named after a police officer that helped scientists navigate the jungle to find the spider following the first sighting.

Brazilian Wandering – Phoneutria fera (South and Central America)

There are eight different species of  Phoneutria , which means "murderess" in Greek, but the P. fera is generally the largest. Though only about half the length of the giant huntsman, this spider is no shrimp, sporting legs that can span up to six inches. P. fera is found in the Brazilian rainforests and urban areas of Brazil and northern South America. The spider gets its English name from wandering the jungle floor at night, rather than maintaining a lair or spinning a web. During the day, it likes to hide in termite mounds, under leaves and, in urban areas, in piles of clothes and shoes. 

Brazilian wandering spiders are also among the most venomous spiders in the world, and fairly aggressive, so don't get too close. The venom has a chemical compound called PhTx3 that can lead to sever pain, inflammation, paralysis and breathing problems. Luckily, an effective antivenom exists, and the spider displays a distinct warning signal before it bites: it raises its two front legs and  sways back and forth . The venom is also considered potentially medically valuable and is being studied for erectile dysfunction treatments.

Orb Weavers – Nephila maculata (southeast Asia), Nephila clavipes (U.S.), Nephila komaci (Africa)

These are among the largest orb weaver spiders in the world. According to Urban, their webs can be as big as eight feet across, and the spiders themselves measure about the size of a large hand’s palm. Orb weavers are common garden spiders—you’ll know them by the spiral-shaped web, large rounded abdomens and long legs. They may look pretty intimidating, but don’t worry; they just want to dine on mosquitoes and other bugs. The orb weavers are also a classic example of extreme sexual size dimorphism, with females growing three to five times the size of the males.

The largest known orb weaver,  Nephila komaci , was discovered in 2009 in Madagascar. Females of this rare spider species can grow up to four to five inches in leg span.  

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Jennifer Billock | | READ MORE

Jennifer Billock is an award-winning writer, bestselling author, and editor. She is currently dreaming of an around-the-world trip with her Boston terrier. Check out her website at jenniferbillock.com .

11 deadliest spiders

From the funnel web spider to the brown recluse, here are some of the deadliest spiders on Earth.

Spiders are some of the most successful arthropods on the planet, having colonized every continent except Antarctica. Not all of these eight-legged arachnids are venomous, but some can be deadly to humans . From the notorious black widow to the ultra-deadly funnel web spider, here are some of the deadliest spiders on Earth.

Brown recluse spider

As their name suggests, brown recluse spiders ( Loxosceles reclusa ) have a shy nature and tend to hide away in dark, sheltered places. However, the brown recluse spider will bite if they feel threatened, and their bites can be deadly. They are usually found in the south and central United States, spanning southeastern Nebraska to southwestern Ohio, south to northwestern Georgia and into Texas.

The brown recluse spider can be dangerous to people because their venom contains a toxin that can cause skin necrosis (rotting). For the most part, symptoms, such as burning and itching at the bite site, as well as fever and nausea, develop a few hours after a bite. In extreme cases, the venom can lead to serious reactions or even death, especially to more vulnerable groups such as young children and the elderly.

Hobo spider

Part of the family of spiders known as the funnel web spiders, the hobo spider ( Eratigena agrestis , formerly Tegenaria agrestis ) can be recognized by it's light to medium brown coloring and the multiple chevron patterns (v-shaped) on its abdomen pointing toward their head. They are often confused with the brown recluse spider (and vice versa), but the brown recluse is much more dangerous to humans. While hobo spiders have been known to bite if they feel threatened, there is much debate about how venomous they actually are. So much so that the Center for Disease Control and Prevention has removed them from their venomous spiders list. However, it's still wise to be cautious as hobo spider bites result in swelling and redness around the area, and can have more severe effects in young children.

Hobo spiders are not great climbers, so you'll find their funnel-shaped webs at ground level. Geographically, they can be found in western North America, in the Pacific Northwest and Great Basin, as well as distributed throughout Europe to Central Asia.

Black widow spider

In the genus Latrodectus , the black widow is one of the most venomous spiders and is found on every continent except Antarctica. In North America, they're commonly found in southern Canada and in the northeastern United States. You can identify the female black widow spider by its shiny black body and distinct red hourglass-shape on the underside of the abdomen. The male black widow is smaller in size, brown or gray in color with small red sports and does not have the hourglass marking.

While both male and female black widows are venomous, only the female is dangerous to humans. The venom of a black widow is reported to be 15 times stronger than that of a rattlesnake, although they don’t deliver as much venom in their bite, so fatalities are rare. That’s not to say a black widow bite isn’t painful! Those unlucky enough to be bitten by a black widow will experience nausea, fever, sweating, restlessness, muscle cramps and labored breathing, and these symptoms may last for several days.

Brazilian wandering spider

Commonly referred to as armed spiders or banana spiders (as they tend to be found hiding within shipments of bananas), the Brazilian wandering spider is one that you'll definitely want to avoid. They belong to the genus Phoneutria , Greek for "murderess," which is quite apt as they are one of the most venomous spiders on Earth.

This arachnid is aggressive, and rather than camping out, the Brazilian wandering spider actively hunts its prey, searching the jungle floor at night. If you ever find yourself in Central and South America, such as Costa Rica or Argentina, watch out! Their neurotoxic venom is extremely painful and affects the nervous system, causing increased sweating and drooling, loss of muscle control, breathing problems, and, in some cases, unwanted prolonged erections.

Yellow sac spider

The yellow sac spiders ( Cheiracanthium) are in the family Cheiracanthiidae and they probably account for more human bites that any other type of spider. These arachnids are distributed all over the globe, from America to Northern Europe, South Africa to India, and even Australia and Japan. They’re nocturnal predators and during the day they hide in small white web cocoons.

Mildly venomous to humans, the yellow sac spider bite can be painful and sometimes misdiagnosed as brown recluse bites. Their venom can cause necrotic legions, as well as redness, swelling and sores around the bite site.

Brown widow spider

Latrodectus geometricus is the scientific name for the brown widow spider. It looks similar to its infamous " cousin " the black widow, right down to the hourglass-shaped marking on its abdomen, but there are some key differences. The brown widow’s marking is orange and yellow rather than red, and as their name suggests, they predominantly have tan and brown mottling and a spiky, rather than smooth, appearance. Believed to originate in South America, the brown widow spider is found all around the world.

The brown widow's venom is less toxic than that of its black cousin. However, it can still be deadly. Although they don't deliver as much venom as a black widow, the brown widow's bite can still cause latrodectism due to its neurotoxic venom. Symptoms of lactrodectism include pain, perspiration, muscle rigidity and vomiting.

Red widow spider

Living mostly in sand dunes in Central and Southern Florida, the red widow spider ( Latrodectus bishop) is another member of the notorious "widow" family. Their venom is just as lethal as brown and black widows, but as they live so far from human contact there has been no recorded bite in medical literature. The female red widow spider's venom is a neurotoxin which is thought to cause prolonged muscle spasms.

The red widow spider has a red-orange head and legs and a black abdomen with yellow rings around red dots. Rather than an hourglass marking like its "cousins," the red widow usually has one or two red marks.

Redback spider

Due to its strikingly similar appearance, the redback spider ( Latrodectus hasselti ) was once thought to be a sub species of the black widow spider, but it is a distinct species. Also known as the Australian black widow, you can find this creepy crawly throughout Australia, Southeast Asia and New Zealand. The redback spider has even been found in Japan, the United Arab Emirates and Belgium due to inadvertent introductions.

Highly venomous, the bite from the female redback spider can be life-threatening. Using its fangs, it injects a complex venom that causes intense pain at the bite area, in addition to sweating and goosebumps. As time goes on, these symptoms worsen and there may also be redness and swelling, as well as nausea, muscle twitching, headache and fever. Respiratory failure may occur in severe cases. Thankfully, in 1956 scientists released a redback spider antivenom which is very effective, even when used several weeks after the initial bite. No deaths have been reported since.

Funnel-web spiders

Normally in the world of spiders it is the female that is more deadly, but for funnel-web spiders ( Atrax ) the male has the more toxic bite. Any attack must be treated quickly with antivenom, especially if a child has been bitten. There have been several recorded fatalities due to the venomous bites of the funnel-web spider, with death occurring within the hour after being bitten. However, since the development of the antivenom in 1981, there haven’t been any more recorded deaths. Predominantly located in southeast Australia (Sydney), funnel-web spiders are also found in New Zealand, Chile and Europe.

Interestingly, animals such as cats and dogs can actually survive a funnel web bite – it takes about 30 minutes for their body to neutralize the toxin – it's just humans who have such a severe reaction. This venom effects the nervous system and causes symptoms such as an elevated heart rate, numbness/tingling of the mouth and difficulty breathing.

Six-eyed sand spider

Found in deserts in southern Africa, the six-eyed sand spider ( Hexophthalma hahni ) buries itself in the sand to ambush unsuspecting prey. The small, stiff hairs that cover the spider helps to hold sand particles in place, adding to its camouflage. It's otherwise known as the six-eyed crab spider due to its crab-like legs.

Another arachnid that produces venom with necrotic effects, the six-eyed sand spider is the most venomous of any of its arachnid relatives, toxicology studies reveal. Scientists have found that there are proteins within their venom that can cause tissue destruction, blood vessel leakage, and thinning of the blood. No antivenom currently exists.

Mouse spider

Black in color with stocky, thick legs and a distinctively bulbous head and jaw regions, the mouse spider ( Missulena ) looks a lot more frightening than its name sounds. One species is located in Chile, another in South America and the rest distributed throughout Australia. They live in soil-covered burrows, popping out the hinged trapdoor top to attack prey.

Their hard, large fangs can cause a deep and very painful bite. However, while scientists believe that the venom of the mouse spider is very toxic, it is rarely injected. As so few cases have been reported, it is thought that mouse spiders don't use a lot of venom or may even "dry bite." Fortunately, funnel-web spider antivenom has proven effective in cases of mouse spider bite.

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Christina is a freelancer writer and editor from the UK. She has a degree in English Language and Literature with geography from the University of Keele, and a Masters in Publishing from Anglia Ruskin University. She covers everything from Lego sets and science kits through to laptops for students. If it helps you learn, she'll help you find it for cheaper.

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Can a Bite From a Brazilian Wandering Spider Cause a Four-Hour Erection?

In many cases, the erection is merely an early warning before the complete shutdown of multiple organ systems., alex kasprak, published aug. 16, 2023.

About this rating

On Aug. 14, 2023, the account First Doctor  posted what it asserted to be an "exclusive" finding on the social media platform X, formerly known as Twitter:

While far from an exclusive — or even a remotely new — finding, the two claims in the tweet were factual. A bite from Phoneutria nigriventer , commonly known as the Brazilian wandering spider, can indeed result in a long-lasting and painful erection, a condition known as priapism when it lasts more than four hours . 

While the toxicity and high risk of death posed by the chemical thought to be responsible for the erections makes its use as a potential erectile dysfunction (ED) therapy challenging, if not literally impossible , it has been used to develop similar chemicals that may have therapeutic potential. 

Phoneutria nigriventer 's erection-causing effects have been known to science since the 1970s. The 1971 book "Venemous Animals and Their Venom" described priapistic effects of this spider's bite on mice and dogs. The authors also included anecdotal reports from humans who had been bitten:

A pattern which resembles that of dog envenomation is also noticed in humans bitten by Phoneutria nigriventer: local unbearable pain, salivation, visual disturbances, sweating, prostration, priapism, and death. 

Research published in 2008 identified the chemical within the venom likely responsible for the erections — a peptide now named PnTx2-6. "[Pn]Tx2-6 enhanced erectile function in [...] rats, via the [Nitrous Oxide] NO pathway," the study reported. "Our studies suggest that [Pn]Tx2-6 could be important for development of new pharmacological agents for treatment of erectile dysfunction."

The interest in this toxin as a treatment for ED stems, in part, because it operates in a completely different way than common ED treatments like Viagra, as reported in 2011 by NBC News:

Viagra, Levitra and other ED drugs on the market work by inhibiting an enzyme called PDE5. To get an erection, a man's body must release nitric oxide, which relaxes the smooth muscle around the arteries of the penis, allowing for his blood vessels to dilate. The nitric oxide is a first step in a series of chemical reactions that allow this muscle relaxation to take place.  One step in the series is cGMP, a signaling molecule that acts to keep the muscles relaxed. PDE5 degrades cGMP. That's a good thing for ensuring that erections don't last forever, but too much PDE5 can mean an erection doesn't happen at all. By blocking the enzyme, PDE5 inhibitors solve the problem. The spider toxin works differently. Instead of affecting PDE5, the compound seems to trigger nitric oxide release, acting directly to relax the smooth muscles. Because about 30 percent of patients don't respond to PDE5 inhibitors, the toxin could provide an alternative to ED treatments currently on the market, [Study author Kenia] Nunes said." 

In 2022, the same research group responsible for identifying PnTx2-6 published a paper arguing, in part, that due to the extreme pain and high toxicity of the chemical, its "therapeutic use is impossible," but that it is "an excellent pharmacological tool for studying erectile function." That study synthesized a new peptide, PnPP-19, based on the toxic original.

Based on studies performed on laboratory mice, PnPP-19 appears to have the potential to cause erections without the pain or toxicity of the spider venom:

This synthetic peptide also potentiates erectile function via NO/cGMP, but it [...] displays nontoxic properties in animals even at high doses. PnPP-19 effectively potentiates erectile function not only after subcutaneous or intravenous administration but also following topical application.

The assertions in First Doctor's post were factual because the priapism caused by Phoneutria nigriventer's bites have been well-documented and well-studied for decades and because the active ingredients in that venom have been used to investigate new ED therapies. As such, we rate the claim as "True."

Bücherl, Wolfgang, and Eleanor E. Buckley. Venomous Animals and Their Venoms: Venomous Invertebrates. Elsevier, 2013.

Nunes, K. P., et al. "Tx2-6 Toxin of the Phoneutria Nigriventer Spider Potentiates Rat Erectile Function." Toxicon : Official Journal of the International Society on Toxinology, vol. 51, no. 7, June 2008, pp. 1197–206. PubMed Central, https://doi.org/10.1016/j.toxicon.2008.02.010.

Silberman, Michael, et al. "Priapism." StatPearls, StatPearls Publishing, 2023. PubMed, http://www.ncbi.nlm.nih.gov/books/NBK459178/.

Silva, Carolina Nunes da, et al. "From the PnTx2-6 Toxin to the PnPP-19 Engineered Peptide: Therapeutic Potential in Erectile Dysfunction, Nociception, and Glaucoma." Frontiers in Molecular Biosciences, vol. 9, 2022. Frontiers, https://www.frontiersin.org/articles/10.3389/fmolb.2022.831823.

"Spider Venom Shows Promise for Treating Erectile Dysfunction." NBC News, 7 Sept. 2012, http://www.nbcnews.com/health/health-news/spider-venom-shows-promise-treating-erectile-dysfunction-flna1B5794477.  

By Alex Kasprak

Alex Kasprak is an investigative journalist and science writer reporting on scientific misinformation, online fraud, and financial crime.

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