--- title: "Brazilian Wandering Spider (Phoneutria nigriventer) | AnimalTracks.wiki" description: "A web-less wandering spider of south-eastern South America that hunts among the vegetation after dark, throws its front legs up when threatened, and carries venom packed with peptides that jam ion channels." image: "https://animaltracks.wiki/images/animals/brazilian-wandering-spider-1.webp" published: "2026-09-01" updated: "2026-09-19" --- # Brazilian Wandering Spider (*Phoneutria nigriventer*) > **Status**: Checked against 4 sources, listed under Sources below. > **Tagline**: A web-less wandering spider of south-eastern South America that hunts among the vegetation after dark, throws its front legs up when threatened, and carries venom packed with peptides that jam ion channels. > **Soundtrack Vibe**: Classic Funk, Soul & Disco // Jorge Ben Jor, "Chove Chuva" > **Soundtrack Links**: [Spotify](https://open.spotify.com/track/6mTfOxORhYlpnTvm7VrL6b) | [YouTube](https://www.youtube.com/watch?v=Ubol9NyLWZc) > **Vibe Match**: Loose acoustic guitar bounce over a rolling, lateral swagger, the same swing as a threat display that rears the body erect, lifts the forelegs and rocks it from side to side. ## Biological Superpowers & Stats - **Taxonomy**: *Phoneutria nigriventer* - **Danger Level**: Deadly - **Conservation Status**: Not Evaluated ([IUCN Red List](https://www.iucnredlist.org/)) - **Superpower**: Venom peptides that jam voltage-gated sodium and calcium channels and the nicotinic acetylcholine receptor - **Habitat**: Forests of central and south-eastern Brazil, Paraguay, northern Argentina, and Uruguay, also banana plantations and buildings - **Diet**: Carnivore (mainly insects and other invertebrates) - **Tags**: arachnid, forest, venomous, nocturnal ## Natural History & Behavior ## No Web, Just Legs The Brazilian wandering spider (*Phoneutria nigriventer*), called *aranha-armadeira* ("armed spider") in Brazil, does not spin a web and wait. A Brazilian public-health leaflet on the genus puts it plainly: it has nocturnal habits, is wandering, and "does not weave a web," sheltering under vegetation or on the ground in forested areas, and sometimes moving into houses and banana plantations. The genus revision says where the feeding happens: *Phoneutria* species live on trees under natural conditions and hunt among the vegetation, and banana plantations come second. The 2001 revision that sorted the genus out counted five species in it, and gave one body-length range for all of them: 17 to 48 millimeters, with no separate figure for *P. nigriventer*. Lifespan is a suborder figure rather than a species one: araneomorphs, the "modern spiders" that make up more than 90% of all living spider species, typically have a shorter lifespan than their tarantula cousins, often 1 to 2 years against the tarantulas' 20-plus. Despite the jungle reputation, this is not an Amazon animal: the revision sorts the genus into four distribution groups, and the Amazonian one is *P. fera* and *P. reidyi*. *P. nigriventer* holds central and south-eastern Brazil, Paraguay, northern Argentina, and Uruguay. Specimens have turned up in Montevideo and Buenos Aires, probably introduced with imported bananas, part of how the genus is often called "banana spider" too. ## Stand Up And Sway The whole genus shares one defensive display: rearing into an erect posture, raising the front legs, and swaying the body from side to side. It is distinctive enough that taxonomists use it as one of the two features that separate *Phoneutria* from *Ctenus* and other ctenid spiders. The wandering habit brings the genus indoors, where it has been found lodged in shoes, behind furniture, and among stacked construction materials, and although *Phoneutria* are essentially wandering, nocturnal spiders, most of the Campinas bites happened during the day and mainly in urban homes. ## Venom Built for Ion Channels *Phoneutria nigriventer* venom is highly complex compared with other neurotoxin-rich venoms, packed with peptides that jam voltage-gated sodium and calcium channels along with the nicotinic acetylcholine receptor, the switches nerve and muscle cells use to fire. Brazil sees roughly 4,000 envenomation cases from this species a year, with symptoms that can include priapism (a prolonged, unwanted erection), high blood pressure, blurred vision, sweating, and vomiting. > **Most bites barely register**, medically speaking. A 13-year study of 422 *Phoneutria* bite patients in Campinas classified 89.8% as mild, 8.5% as moderate and 0.5% as severe. The two severe cases were children, nine months and three years old, and the older of the two died nine hours after the bite. That same venom is now studied for something else entirely: its peptides show therapeutic effects in a range of disease models including chronic pain, Huntington's disease and glaucoma. ## Frequently Asked Questions ### How dangerous is a bite from the Brazilian wandering spider, really? Out of 422 bite patients from the genus Phoneutria seen over 13 years at a poison control center in Campinas, Brazil, only 2.3% of the patients were treated with antivenom. The authors named children under 10 years of age and adults over 70 years of age as the highest risk groups, and reported that ten deaths had been attributed to Phoneutria in Brazil to that point. *(Source: [Bucaretchi et al. 2000]())* ### Why does it rear up and wave its front legs? It is a defensive display: an erect posture with the front legs raised and the body swaying from side to side. Taxonomists use it as one of the two features that separate Phoneutria from Ctenus and other ctenid spiders; the other is the dense scopulae, brush-like pads of hair, on the palps. *(Source: [Simó & Brescovit 2001]())* ### Could this spider's venom actually help people? Peptides from Phoneutria nigriventer venom have shown therapeutic effects in models of Huntington's disease, glaucoma and erectile dysfunction as well as chronic pain. The same venom that jams the ion channels nerve and muscle cells use to fire is now being mined for new medicines. *(Source: [Cardoso et al. 2023]())* ## Sources 1. [Simó & Brescovit (2001). Revision and cladistic analysis of the Neotropical spider genus Phoneutria Perty, 1833 (Araneae, Ctenidae), with notes on related Cteninae. Bulletin of the British Arachnological Society 12(2): 67-82.]() 2. [Bucaretchi et al. (2000). A clinico-epidemiological study of bites by spiders of the genus Phoneutria. Revista do Instituto de Medicina Tropical de São Paulo.]() 3. [Cardoso et al. (2023). Holistic profiling of the venom from the Brazilian wandering spider Phoneutria nigriventer by combining high-throughput ion channel screens with venomics. Frontiers in Molecular Biosciences.]() 4. [Série Educativa da Fauna Sinantrópica: Aranha Phoneutria nigriventer. Coordenadoria de Vigilância em Saúde, Prefeitura de São Paulo, 2020.]() *Published September 1, 2026. 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