Brazilian Wandering Spider: Size, Bite, Diet and Other Facts 

Brazilian Wandering Spider

The Brazilian Wandering Spider is a venomous arachnid with a fearsome reputation. This South American rainforest dweller packs a powerful punch, but don’t let its nickname “banana spider” fool you – they’re active hunters, not web-spinners. Despite their size and venom, bites are uncommon as they’re typically shy.

The Brazilian Wandering Spider has garnered significant attention due to its potent venom, which makes it one of the world’s most venomous spiders. Understanding its biology and behavior is crucial for both scientific research and public safety.

Scientific classification

The Brazilian Wandering Spider belongs to the family Ctenidae within the order Araneae. Its scientific classification is as follows:

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

The Brazilian Wandering Spider goes by various common names, including “armed spider,” “banana spider,” and “wandering spider.” Synonyms for this species may include Ctenus, which was formerly used for some Phoneutria species.

Distribution and habitat


  • South American: Found throughout most of South America east of the Andes mountains, including countries like Brazil (their namesake), Argentina, Paraguay, and up into northern regions.
  • Central American Touch: A few species even reach southern Central America.


  • Rainforest Dwellers: Primarily found in the lush rainforests of South America.
  • Not Picky Places: They can also adapt to other habitats like the Atlantic Forest and even some urban areas.
  • Daytime Hideouts: While they wander at night, they seek shelter during the day in places like termite mounds, under rocks, or even (unintentionally) in bananas!

Physical Characteristics

 Size and weight

The Brazilian wandering spider is a creepy crawly giant. Their bodies can grow up to 2 inches (5 centimeters) long, but that’s not the scary part. Their legs can span a whopping 7 inches (18 cm), making them look even bigger. They are one of the biggest true spiders by body weight and size.

Despite their impressive leg span, Brazilian wandering spiders are relatively light. They only weigh around 6 grams, which is about the same as two pennies. While they might look imposing, they’re not the heaviest arachnids around.

Coloration and markings

These spiders exhibit a range of colors, including brown, black, and sometimes reddish hues. They often have distinctive markings on their bodies, which can vary between species. These markings may include stripes or patterns that serve as a key identification feature.

Notable features

One of the most notable features of the Brazilian Wandering Spider is its elongated, robust body and long, agile legs. They have sharp fangs, which they use to inject venom into their prey or in self-defense.

Sexual dimorphism

Sexual dimorphism is evident in this species. Females are larger and bulkier than males, while males have longer, more slender legs. Additionally, males possess specialized structures known as pedipalps, which are used during mating.

In the following sections of this article, we will delve deeper into the behavior, venom, and ecological role of the Brazilian Wandering Spider, shedding light on why this species has both fascinated and instilled fear in those who encounter it.

 Behavior and Ecology

Brazilian Wandering Spider Behavior and Ecology

 Nocturnal habits

Brazilian Wandering Spiders are primarily nocturnal creatures. They are most active during the night, venturing out of their daytime hiding places to hunt for prey and engage in mating activities. Their nighttime activity allows them to avoid predators and reduce the risk of desiccation in the hot tropical sun.

Hunting and feeding behavior

These spiders are agile hunters and primarily feed on insects, small vertebrates, and other arachnids. They do not build webs to capture prey but instead rely on their excellent senses, including acute vision and touch, to locate and stalk their victims. They often wander in search of food and are known for their swift and lethal strikes. Once they subdue their prey, they inject venom to immobilize it before feeding.

Brazilian Wandering Spiders (Phoneutria) are active hunters and have distinctive feeding behaviors. Here’s an overview of their feeding habits:

  1. Active Predators: Brazilian Wandering Spiders are not web-builders like many other spider species. Instead, they are active predators. They actively roam their environment in search of prey rather than waiting for insects to stumble into a web.
  2. Hunting Strategy: When hunting, these spiders use their excellent senses, including acute vision and touch, to locate potential prey. They are known for their agility and speed, which they use to stalk and capture their victims. They have sharp fangs, which they use to deliver a venomous bite to immobilize their prey.
  3. Diet: Their diet consists primarily of insects and other arthropods, but they are opportunistic feeders and may consume a variety of small creatures, including small vertebrates such as frogs and lizards when the opportunity arises.
  4. Venom Use: Brazilian Wandering Spiders inject venom into their prey to immobilize and partially digest it. Their venom contains neurotoxins that affect the nervous system of their victims. Once the prey is incapacitated, the spider can feed on it at its leisure.
  5. Feeding Process: After subduing their prey with a venomous bite, the spider uses its chelicerae (fangs) to break down the prey’s tissues. The venom also helps in predigestion, turning the prey’s insides into a semi-liquid form that the spider can ingest. They can consume both the internal fluids and solid parts of their prey.
  6. Frequency of Feeding: The frequency of feeding can vary depending on factors such as the availability of prey and the spider’s size. Generally, they need to feed periodically to sustain their energy and growth. Spiderlings may require more frequent meals to support their rapid growth, while adults can go longer periods between meals.

Overall, the Brazilian Wandering Spider’s feeding strategy is well-suited for their active and wandering lifestyle, allowing them to efficiently capture and consume a variety of prey in their natural habitat.

Role in the ecosystem

The Brazilian Wandering Spider plays a vital role in controlling insect populations within its habitat. By preying on a variety of insects and other small creatures, they help maintain ecological balance. Additionally, their presence in the rainforest ecosystem contributes to the overall biodiversity and food web.

Mating and reproduction

Mating in Brazilian Wandering Spiders is a complex and potentially dangerous process. Male spiders must carefully approach and court a receptive female to avoid being mistaken for prey. They use specialized pedipalps to transfer sperm to the female’s reproductive organs. After successful mating, females lay egg sacs containing hundreds of eggs. They guard these sacs and ensure the survival of their offspring until they hatch.

 Lifespan and growth

The lifespan of Brazilian Wandering Spiders varies between males and females. Males generally have a shorter lifespan, typically living for a few months to a year after reaching maturity. Females, on the other hand, can live for several years. The growth of these spiders involves a series of molts, during which they shed their exoskeletons to accommodate their increasing size. Molting is a vulnerable period in their lives as their new exoskeleton is initially soft and requires time to harden.

Venom and Envenomation

Composition of venom

The venom of Brazilian Wandering Spiders is a complex mixture of neurotoxins, cytotoxins, and other enzymes. One of the most significant components is a neurotoxin called PhTx3, which targets the nervous system of their prey.

Toxicity and effects on humans

The venom of these spiders is highly potent and can be lethal to their prey. In humans, envenomation can cause a range of symptoms, including intense pain, muscle cramps, fever, nausea, and in severe cases, paralysis and death. It’s important to note that while their venom is potent, actual fatalities from Brazilian Wandering Spider bites are rare due to the availability of medical treatment.

First aid and medical treatment

In the event of a Brazilian Wandering Spider bite, immediate medical attention is crucial. First aid measures may include cleaning the wound and applying ice to reduce pain and swelling. However, the primary treatment involves antivenom, which can counteract the effects of the spider’s venom.

Cases of envenomation and fatalities

Although fatalities from Brazilian Wandering Spider bites are uncommon, there have been documented cases of severe envenomation, especially in regions where medical treatment is not readily available. These spiders are generally non-aggressive and will bite humans only in self-defense when provoked, or if they feel cornered.

Understanding the behavior, ecology, and venomous nature of the Brazilian Wandering Spider is crucial for both scientific research and public awareness, helping to minimize the risk of envenomation and promote coexistence with this remarkable but potentially dangerous arachnid.

Brazilian wandering spider life cycle

The Brazilian wandering spider has a fascinating life cycle that revolves around hunting and motherhood. Here’s a breakdown:

  1. Egg Haven: After mating, the female lays hundreds, sometimes even a thousand, eggs in a silken sac. This becomes their protected nursery.
  2. Tiny Terrors: Hatching from the eggs emerge translucent spiderlings called larvae.
  3. Nymph Stage: The larvae molt a few times, transforming into nymphs. Think of them as mini-adults but without the ability to reproduce yet.
  4. Shedding for Size: As nymphs grow, they undergo multiple molts, shedding their outer shell to accommodate their larger bodies.
  5. Ready to Roam: After the final molt, the spider emerges as a full-fledged adult, complete with reproductive organs. Now, they can join the wandering lifestyle and continue the cycle.

Egg Stage

The life cycle begins when a female Brazilian Wandering Spider lays her eggs. She typically creates an egg sac made of silk and deposits it in a concealed location, such as a tree hollow or leaf litter. Inside the sac, she may lay hundreds of eggs. The female guards the egg sac and ensures its protection until the spiderlings hatch. The duration of the egg stage varies depending on environmental conditions but generally lasts for a few weeks.

Spiderling Stage

After the incubation period, spiderlings (young spiders) emerge from the egg sac. They are extremely vulnerable at this stage and rely on their mother’s protection and guidance. Spiderlings are miniature versions of adult spiders but lack the full coloration and size. They disperse from the nest once they have molted and are capable of hunting on their own. During this stage, they grow rapidly by molting, shedding their exoskeletons to accommodate their increasing size.

Juvenile Stage

As spiderlings continue to molt and grow, they progress into the juvenile stage. During this phase, their coloration becomes more distinct, and they start to develop the characteristic features of adult Brazilian Wandering Spiders. They become increasingly independent and begin to exhibit hunting behaviors. The duration of the juvenile stage can vary but often lasts several months.

Sub-Adult Stage

The sub-adult stage is an intermediate phase between juvenile and adult. At this point, the spiders are closer in size and appearance to adults but have not yet reached sexual maturity. They continue to molt, with the frequency of molting gradually decreasing as they approach adulthood. Sub-adult spiders may exhibit more territorial behaviors as they compete for resources and prepare for eventual mating.

Adult Stage

Upon reaching sexual maturity, Brazilian Wandering Spiders enter the adult stage. This is when they are fully developed and capable of reproduction. Females are larger and bulkier than males, and males possess specialized structures called pedipalps, which they use during mating. Adult spiders engage in mating activities, and females lay eggs to continue the life cycle. Adult Brazilian Wandering Spiders can live for several years, with females typically having longer lifespans than males.

Understanding the life cycle of these spiders is essential for studying their behavior, reproductive biology, and population dynamics. It also provides insights into their adaptation strategies in the complex ecosystems of South and Central America.

Brazilian Wandering Spider Bite

Brazilian Wandering Spider Bites
Brazilian Wandering Spider Bites

Brazilian Wandering Spiders are known for their potent venom and, occasionally, their bites on humans. While bites are relatively rare due to the spider’s non-aggressive nature, understanding the consequences of a bite is crucial for public safety.

Studying Brazilian Wandering Spider bites is of great interest for several reasons. It helps healthcare professionals provide appropriate medical treatment, raises awareness among communities in spider habitats, and contributes to our understanding of venomous arachnid envenomations.

The venom of Brazilian Wandering Spiders is a complex mixture of neurotoxins, cytotoxins, and enzymes. It contains various components, including PhTx3, which is a potent neurotoxin affecting the nervous system.

Brazilian Wandering Spider bites can have a range of effects on the human body, including intense pain, muscle cramps, fever, nausea, and in severe cases, paralysis. The severity of the symptoms depends on factors such as the amount of venom injected and the individual’s sensitivity to the venom. There are several types of spider bites.

Symptoms of a Brazilian Wandering Spider Bite

Local symptoms

  • Intense pain
  • Swelling
  • Redness
  • Itching or burning sensation
  • Formation of blisters or lesions

Systemic symptoms

  • Muscle cramps and spasms
  • Abdominal pain
  • Nausea and vomiting
  • Elevated heart rate
  • Hypertension (high blood pressure)
  • Respiratory distress

Severity and variations

The severity of Brazilian Wandering Spider bite symptoms can vary widely. In some cases, symptoms may be mild and resolve on their own, while in severe envenomations, life-threatening complications can occur. Individual reactions to the venom can also vary, making it challenging to predict the exact outcome of a bite.

First Aid and Immediate Response

Steps to take after a bite

Immediate response to a Brazilian Wandering Spider bite should include:

  • – Washing the bite area with soap and water.
  • – Applying a clean, cool compress to reduce pain and swelling.
  • – Immobilizing the affected limb or area.
  • – Keeping the bite victim calm to prevent an elevated heart rate.

Do’s and don’ts in case of a bite


  • – Seek medical attention promptly.
  • – Take note of the spider’s appearance (if possible) to aid identification.
  • – Keep the bite victim still and calm to reduce the spread of venom.


  • – Do not try to suck out venom or make incisions at the bite site.
  • – Avoid applying tourniquets.
  • – Don’t use ice directly on the skin as it can worsen tissue damage.

Seeking medical attention

Medical attention is essential after a Brazilian Wandering Spider bite, even if symptoms appear mild initially. Antivenom is available and can be administered to counteract the effects of the venom. Medical professionals can also manage symptoms and monitor for potential complications.

Complications and Long-Term Effects

Potential complications

Complications from Brazilian Wandering Spider bites can include:

  • – Severe muscle spasms
  • – Respiratory distress
  • – Cardiovascular issues
  • – Kidney failure (rare)
  • – Allergic reactions to antivenom

Long-term consequences

Long-term consequences of a bite can vary depending on the severity and medical treatment received. Some individuals may experience lingering pain, muscle weakness, or psychological trauma following a severe envenomation.

Recovery and rehabilitation

Recovery from a Brazilian Wandering Spider bite typically involves medical treatment, rehabilitation for muscle and nerve damage, and psychological support for individuals affected by the experience. Rehabilitation may include physical therapy to regain muscle strength and function. Prompt medical attention and appropriate care are crucial for minimizing long-term effects and complications.

Facts of Brazilian Wanding Spider

Here are 10 creepy crawly facts about the Brazilian Wandering Spider:

  1. Big and Hairy: These spiders are giants! Their bodies can grow up to 2 inches (5 centimeters) long, with a leg span of up to 7 inches (18 cm). They are covered in hairs, making them appear even bigger.
  2. Wanderlust: They are aptly named – Brazilian wandering spiders don’t spin webs. Instead, they wander the forest floor at night in search of prey.
  3. Venomous Bite: Their venom is considered one of the most potent among spiders. A bite can cause severe pain, swelling, sweating, nausea, and even priapism in males. Thankfully, bites are rare as they are typically shy and defensive.
  4. Not So Fond of Bananas: While sometimes called ‘banana spiders,’ they are not typically found in bananas. They might, however, take shelter in them during transport, which is how they might end up in a faraway land.
  5. Rainforest Resident: These spiders are native to the rainforests of South America, particularly in Brazil.
  6. Fearsome Feasters: They’re active hunters and will eat almost anything they can overpower, including insects, lizards, frogs, and even small rodents.
  7. Mom’s the Word: Female Brazilian wandering spiders are dedicated mothers. They lay hundreds of eggs in a silken sac and fiercely guard them until they hatch.
  8. Multiple Molts: Like all spiders, Brazilian wandering spiders grow through molting. They shed their exoskeleton multiple times as they grow into adults.
  9. Mating Dance: Male Brazilian wandering spiders perform a elaborate mating dance to attract a female.
  10. Medicinal Potential: Despite their scary reputation, the venom of the Brazilian wandering spider is being studied for its potential use in treating erectile dysfunction.

What happens if a Brazilian Wandering Spider bites a man?

A Brazilian Wandering Spider bite on a man can cause a range of symptoms, some severe:

  • Pain: The bite is known for causing intense, localized pain at the site.
  • Autonomic effects: Sweating, nausea, and increased heart rate are common.
  • Priapism: In some cases, males may experience a prolonged and painful erection (priapism). This is due to a component in the venom.
  • Muscle paralysis: Severe bites can lead to muscle paralysis, which can affect breathing in rare cases.

However, it’s important to remember:

  • Bites are uncommon as these spiders are typically shy and defensive.
  • Antivenom is available and effective in treating bites.

If bitten, seek medical attention immediately. Early treatment can help prevent complications and ensure a full recovery.

How poisonous is a Brazilian Wandering Spider?

Brazilian Wandering Spider packs a nasty venomous punch, considered one of the strongest among spiders. Bites are rare though, as they’re shy and prefer to escape trouble.

What is the world’s deadliest spider?

The term “deadliest” can be subjective and depends on how one defines it (e.g., based on venom potency or human fatalities). However, the Brazilian Wandering Spider (Phoneutria) is often considered one of the most venomous spiders in the world. Another spider often mentioned in discussions of venom toxicity is the Sydney Funnel-web Spider (Atrax robustus and Atrax formosus), found in Australia. These spiders are known for their potent venom and have caused fatalities in the past.

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