What does it do when it feels threatened?

Rears up and raises its front legs

What should you do if someone is bitten?

Wash the bite, tell an adult and see a doctor

Most big spiders found in imported bananas turn out to be…

Harmless look-alikes such as Cupiennius

Why are scientists studying its venom?

To find new medicines, such as painkillers

Brazilian Wandering Spider

Phoneutria

Brazilian wandering spiders are the 9 species of the genus Phoneutria, large night-hunting spiders found from Central America to northern Argentina. This card focuses on the best-studied species, Phoneutria nigriventer of Brazil’s Atlantic Forest. They hunt on foot instead of using webs, warn enemies with a raised-leg threat display and have medically important venom, although most bites are mild and Brazil has an antivenom.

Also known as Aranha-armadeira, Phoneutria, Armed Spider

Brazilian wandering spider abilities

4 legs raised high to warn
Threatened, it rears up on its back legs, lifts its 4 front legs high and sways, flashing banded legs and red jaw hairs.
- The pose makes the spider look bigger, and it shifts towards whatever is bothering it.
- This display is so typical that scientists use it as one of the features that define the genus.
- Phoneutria tend to hold their ground rather than run. Brazil’s health ministry says one can lunge up to about 40 cm, so back away slowly.
- The display is a warning for predators: the spider is defending itself, not hunting you.
Sources [2, 5, 13, 16]
0 webs used to catch prey
It doesn’t catch food in a web. After dark it walks the forest floor and low plants, hunting on foot.
- By day it hides; at night it actively searches the ground and low vegetation for prey.
- Its silk is for egg sacs and for wrapping food, not for traps.
- In one Amazon study, 53% fewer wandering spiders came out to hunt on nights after daytime rain. Scientists think the damp may mask the smell of prey.
- Young wandering spiders often hunt on plants, where they may avoid bigger spiders on the ground.
Sources [5, 11, 15, 17]
1,000s of strain sensors in a spider’s skinStill debated
Hairs and tiny slits on its legs pick up air movements and ground vibrations, so it can notice prey and danger in the dark.
- Slender hairs called trichobothria swing with the faintest air currents, from any direction.
- Thousands of slit-shaped sensors in a spider’s hard skin work like strain gauges and can tell a prey animal’s vibrations from wind.
- Most of this science comes from Cupiennius, a look-alike hunting spider: it feels the air from a flying fly about 3.8 cm away.
- Scientists suggest young Phoneutria may sit on large leaves partly to feel approaching predators. How much Phoneutria relies on vibrations hasn’t been measured.
Sources [5, 9, 12, 18, 19]
2–4–2 eyes per row
Eight eyes sit in three rows, 2, then 4, then 2: the family pattern of wandering spiders.
- Phoneutria was first told apart from other spiders by its curved middle row of eyes.
- In many spiders, some of the eyes have a mirror-like layer (the tapetum) behind them that helps in dim light.
- Most spiders see little more than light, dark and movement, and lean on touch, vibration and taste instead.
Sources [1, 2, 3]
40+ nerve toxins described
Its venom is a cocktail of small proteins that act on nerves. Scientists are testing some of them as starting points for new medicines.
- More than 40 nerve-acting toxins have been described in P. nigriventer venom, and a study of its venom genes and proteins found 98 toxin sequences, many of them new.
- In lab animals, single toxins eased pain (Phα1β and Tx3-3), and an eye drop based on part of a toxin lowered the eye pressure linked to glaucoma.
- The venom causes strong pain, yet some of its toxins block pain: researchers call it a double-edged sword.
- None of these is an approved medicine yet. They are still being tested in animals.
Sources [10, 20, 21, 22, 23, 24]
18 cm leg span
Its body is 1.7–4.8 cm long, and with legs stretched out a big one can span up to 18 cm.
- Brazil’s health ministry gives armed spiders a body of up to 4 cm and a leg span of 15 cm.
- Scientists call P. nigriventer one of the largest “true spiders”.
- It isn’t the world’s biggest spider: the Goliath birdeater tarantula reaches a 28 cm leg span.
How wide, legs and all
Brazilian wandering spiderup to 18 cm
Goliath birdeater tarantulaup to 28 cm
Recluse spider (Brazil)up to 3 cm
Leg spans for the wandering spider and the tarantula; total length with legs for the recluse.
Sources [2, 4, 10, 13]
96 kinds of prey found by DNA
It eats almost anything it can overpower: mostly insects and spiders, plus the odd small lizard or frog.
- DNA from the guts of Colombian wandering spiders (studied as P. boliviensis) revealed 234 prey items from 96 kinds of animals, mostly flies, moths, beetles and crickets.
- Field records include geckos and tree frogs, and P. nigriventer has been seen eating frogs in Brazil.
- In lab tests on a Colombian species, the venom worked much faster on geckos than on spiders.
- High-speed video of three wandering spider species shows them flipping spider prey over to bite its underside, so it can’t fight back.
Sources [5, 25, 26, 27, 28]

Tap a pin on the model or a part below.

8 eyes in 3 rows
- Eight eyes sit in three rows, 2, then 4, then 2: the typical pattern of the wandering spider family, Ctenidae.
- When Phoneutria was first described, in 1833, it was picked out by its curved middle row of eyes.
- Like most spiders, it relies more on touch and vibration than on sharp eyesight.
Sources [1, 2, 3, 4]
10.4 mm venom gland length
- The jaws (chelicerae) of many Phoneutria species are covered in bright red hairs, which it shows off when threatened.
- Venom is made in glands inside the jaws and flows out through the fangs.
- Its venom glands, up to 10.4 mm long, are the largest known in any spider.
- Spiders can’t chew: they pour digestive juices onto their prey and suck up the liquid.
Sources [4, 5, 6]
4 legs raised to warn
- In many species the undersides of the two front pairs of legs have black bands with yellow or white ones between.
- The bands stay hidden until the spider rears up in its threat display.
- Colour is not a reliable way to tell the 9 Phoneutria species apart: experts use identification keys based on other body features.
Sources [5, 7]
- The palps are the short, leg-like feelers beside the jaws. Spiders use them to handle food, touch and taste.
- Thick brushes of hair on the palps are one of the features that set Phoneutria apart from related spiders.
- In adult males the palp tips are modified as mating organs.
Sources [2, 8, 9]
1.7–4.8 cm body length
- The front half of the body carries the eyes, jaws, palps and all 8 legs, under a hard shield called the carapace.
- Phoneutria are medium to large spiders: 1.7–4.8 cm long, not counting the legs.
- Scientists call P. nigriventer one of the largest “true spiders” alive.
Sources [2, 8, 10]
- The back half holds the silk glands, the heart and much of the gut.
- It is brown or grey, and some species have two rows of pale spots on top.
- The pattern varies even within one species, so it can’t be used to identify them.
Sources [5, 8]
Up to 4 silk egg sacs
- It doesn’t build a web to catch prey, but it still makes silk.
- A female wraps her eggs in up to 4 silk egg sacs.
- In Colombia, a close relative was seen wrapping prey in silk and fixing it to a perch with quick dabs of its front spinnerets.
- Newly hatched spiderlings spin a small, messy web and stay in it until their next moult.
Sources [5, 11]
18 cm leg span
- With its legs stretched out, a Phoneutria can measure up to 18 cm across.
- Fine hairs (trichobothria) feel tiny air movements, and slit-shaped sensors in the leg skeleton feel vibrations.
- In the threat display it stands on its back two pairs of legs.
- Like other spiders, it can drop a leg to escape a predator, and young spiders grow it back at their next moult.
Sources [2, 4, 5, 9, 12]
- By day it hides in plants, tree crevices or even termite mounds, then comes out to hunt at night.
- In Brazil it shelters under logs and in palms, bromeliads and banana leaves, and sometimes in shoes, behind furniture or in piles of building materials.
- Most species outside the Amazon live in Brazil’s Atlantic Forest; in the Amazon they live in forests and plantations too.
- Young Amazon wandering spiders climb onto plants, and one species often sits on small palms.
Sources [2, 5, 13, 14, 15]

Real Brazilian wandering spiders

Photos from Wikimedia Commons. Some of them can repaint the 3D model.

Phoneutria nigriventer in São Paulo state, BrazilPhoto: Rodrigo Tetsuo Argenton, CC BY-SA 4.0
Adult femaleThe full warning kit: banded front legs and red jaw hairs. An adult female P. nigriventer gives nearly 3 times as much venom as an adult male.Makes up to 4 silk egg sacs and keeps them with herThe threat display: front legs up, bands and red jaw hairs on show. Photo: deboas, CC BY 4.0
Seen from above: a 1.7–4.8 cm body and long legsPhoto: Rodrigo Tetsuo Argenton, CC BY-SA 4.0
Adult maleLonger legs for its size, and palp tips modified for mating. In one measured pair (P. boliviensis), the male’s front leg was 53 mm long and the female’s 33 mm, with bodies about 21 mm long.Wanders widely from March to May looking for femalesAn adult male, with long legs. Photo: charlisaurio, CC BY 4.0
SpiderlingNewly hatched spiderlings have an extra claw on each leg and spin a small web. Venom from 2–3-month-old P. nigriventer did not kill mice at the doses tested; it gets stronger as the spider grows.Can catch prey as soon as it leaves the egg sac; grown up at about 3 yearsA young wandering spider on a leaf. Photo: michaelbakkerpaiva, CC BY 4.0
Phoneutria keyserlingi, a close relative, in southern BrazilPhoto: Alessandher Piva, CC BY 4.0
Phoneutria fera out at night in French GuianaPhoto: Bernard Dupont, CC BY-SA 2.0
Camouflaged in leaf litter, BrazilPhoto: Thiago Gonçalves Coronado Antunes, CC BY-SA 4.0
A Phoneutria in Yasuní National Park, EcuadorPhoto: Charles J. Sharp, CC BY-SA 4.0
Phoneutria nigriventer on the movePhoto: Rodrigo Tetsuo Argenton, CC BY-SA 4.0

Brazilian wandering spider by the numbers

Measured by scientists and health agencies, with comparisons you can picture.

Body: 1.7–4.8 cm; body length across Phoneutria species⁠[2]
Leg span: up to 18 cm; with legs stretched out; Wandering spider18 cmGoliath birdeater28 cm; The Goliath birdeater tarantula reaches 28 cm⁠[2, 4]
Species: 9; in the genus Phoneutria⁠[7]
Eyes: 8; in rows of 2, 4 and 2⁠[1]
Eggs: 3,000+; from one P. nigriventer female, in up to 4 egg sacs⁠[5]
Lifespan: up to 6 yrs; in captivity; adult at about 3 years⁠[5]
Toxins: 40+; nerve-acting toxins described in its venom⁠[20]
Venom gland: 10.4 mm; long: the largest known in any spider⁠[6]
Mild bites: ≈90%; of 422 bite patients in a Brazilian hospital study; Severe: 0.5%⁠[33]
Antivenom: 2.3%; of those patients needed it; most needed only pain relief⁠[33]

Brazilian wandering spider myths and facts

Tap Myth or Fact for each claim, then check the answer.

0 of 8 answered

“Bananas from the shop often carry Brazilian wandering spiders.”
“It is the deadliest spider in the world.”
“Guinness World Records lists it among the most venomous spiders.”
“Brazilian wandering spiders chase people.”
“It catches its food in a web.”
“Its venom is being studied to make new medicines.”
“Every bite needs antivenom.”
“Spiders are insects.”

Staying safe around Brazilian wandering spiders

Bites are uncommon and most are mild, but every bite should be seen by a doctor. These numbers show where and how to be careful.

≈90%
of bites were mild
In a study of 422 patients in Brazil, about 9 in 10 had only pain and some swelling around the bite. Severe cases were 0.5%, in young children.⁠[33, 39]
2.3%
needed antivenom
Brazil’s anti-arachnid antivenom, made at the Instituto Butantan, covers Phoneutria. It is free in public hospitals and used only for moderate or severe cases.⁠[33, 40, 16, 41]
54.5%
of bites happened at home
Most were on the feet (41%) or hands (34%). Shake out shoes, clothes and gloves, wear gloves for garden work and never put hands into holes or under logs.⁠[33, 32]
Jan–May
busiest months in Brazil
Males wander looking for mates at this time of year. Keep beds away from walls and close gaps under doors at dusk.⁠[42, 5, 32]
3 steps
if someone is bitten
Wash the bite, tell an adult and go to a doctor or hospital. A clear photo of the spider helps, but never try to catch it. Skip home remedies.⁠[16]

General information, not medical advice. In an emergency in Brazil, call SAMU on 192.

Brazilian wandering spider records

Superlatives and record holders, each checked against its source.

Largest venom glands of any spider
up to 10.4 × 2.7 mm
Phoneutria wandering spiders
Guinness World Records, cited in a 2017 review of spider records⁠[6]
Guinness “most venomous spiders”
Shared title
Phoneutria and Australian funnel-webs
based on venom strength in lab mice⁠[37]
One of the largest true spiders
up to 18 cm
Phoneutria nigriventer
leg span in the genus; bodies up to 4.8 cm⁠[10, 2]
Smallest Phoneutria
≈2 cm
Phoneutria boliviensis
measured adults were about 20–21 mm long⁠[30]
Smallest range of any Phoneutria
2 states
Phoneutria bahiensis
known only from Bahia and Espírito Santo, Brazil; on Brazil’s list of threatened species⁠[5, 43]

Life of a Brazilian wandering spider

A year in the life of P. nigriventer, with gaps filled from a close relative where noted.

March–May
Males go wandering
Adult males roam widely looking for females. This is when most bites happen in Brazil.⁠[5, 33]
April–May
Mating
Mating happens mostly in April and May. In a close relative, the male simply climbs onto the female instead of courting from a distance.⁠[5, 11]
After mating
Egg sacs
A female makes up to 4 silk egg sacs, with more than 3,000 eggs in total, and keeps them with her.⁠[5]
≈1 month
Hatching
In a close relative, 430–1,300 spiderlings came out of each sac 28–34 days after it was made.⁠[11, 30]
First weeks
A first web
Spiderlings of the close relative spin a small, messy web and stay in it until their next moult. Young P. nigriventer can catch prey as soon as they leave the sac.⁠[11, 5]
Years 1–2
Moult after moult
It sheds its skin 5–10 times in its first year and 3–7 times in its second. Its venom gets stronger as it grows.⁠[5, 31]
≈3 years
Grown up
After 2–3 more moults in its third year, P. nigriventer becomes adult. The Colombian relative grew up faster, in 300–465 days.⁠[5, 11]
Up to 6 years
A long life
In captivity P. nigriventer can live up to 6 years.⁠[5]

Brazilian wandering spider vs look-alikes

Big brown spiders from Latin America are easy to mix up. Here is how the wandering spider compares with a harmless banana-box look-alike and another medically important spider.

Brazilian wandering spider (Phoneutria) vs Cupiennius banana spider vs Chilean recluse
	Brazilian wandering spider	Cupiennius “banana spider”	Chilean recluse
Scientific name⁠[7, 44, 45]	Phoneutria (9 species)	Cupiennius (11 species)	Loxosceles laeta
Family⁠[7, 44, 45]	Ctenidae (wandering spiders)	Trechaleidae (moved from Ctenidae in 2019)	Sicariidae (recluse spiders)
Where⁠[46, 47, 44, 45]	Central America to northern Argentina	Mexico, Central America, the Caribbean and northern South America	South America; carried to other countries
Tell-tale sign⁠[5, 13]	Black-and-pale bands under the front legs; red jaw hairs	Black dots on white (C. getazi) or bright red (C. coccineus) under the front legs	A dark violin-shaped mark on the front body; 6 eyes in 3 pairs
Web to catch prey?⁠[5, 18, 19, 13]	No, hunts on foot at night	No, hunts on foot	Yes, messy cotton-like webs
Size⁠[2, 5, 34, 13]	Body 1.7–4.8 cm; up to 18 cm with legs	Large and often mistaken for Phoneutria	Body ≈1 cm; up to 3 cm with legs (recluses in Brazil)
Danger to people⁠[33, 5, 39]	Medically important; most bites mild	Largely harmless	Medically important; bites can damage skin
Antivenom in Brazil⁠[40]	Yes: anti-arachnid antivenom	Not needed	Yes: anti-recluse or anti-arachnid antivenom

Even experienced arachnologists have mistaken harmless Cupiennius for Phoneutria. If in doubt, don’t touch: let an expert identify it.

Is the Brazilian wandering spider endangered?

No Phoneutria species has been assessed for the IUCN Red List. Some live happily around farms and towns, but one species is threatened and much of their forest is gone.

IUCN Red List

Not Evaluated (NE)

Trend unknown

P. nigriventer copes with plantations, gardens and towns and lives at high densities in some places. Most other species are forest spiders. Without assessments, nobody knows whether their numbers are changing.⁠[5, 14]

Not evaluated by the IUCN Red List

Threats

Forest loss≈90%
Nearly 90% of Brazil’s Atlantic Forest, home of most Phoneutria outside the Amazon, has been cleared over the past 500 years.⁠[48, 2]
Tiny ranges
P. bahiensis lives only in Atlantic Forest and coastal restinga in Bahia and Espírito Santo, and is on Brazil’s list of threatened species.⁠[43, 5]

What’s helping

Forest restoration+10–20 points
The Atlantic Forest Restoration Pact, a network of more than 250 groups, raised restored forest cover by 10–20 percentage points on the land it supported.⁠[48]
Protected areas11
Eleven protected areas lie in the best habitat predicted for P. bahiensis.⁠[43]
Citizen science
Photos shared on iNaturalist have helped scientists map where Phoneutria species live, which also shows where bites are more likely.⁠[30]

Brazilian wandering spider quiz

12 questions. Every answer is somewhere on this page.

Question 1 of 12Score 0

How many eyes does a Brazilian wandering spider have?

Brazilian Wandering Spider field notes

Diet, food web, safety and badges from the Snappit field guide.

Diet & Feeding

A nocturnal hunter, it eats insects and small creatures it finds on the forest floor.

Primary Foods

insects
other spiders
small amphibians
small reptiles
Foraging Method: Pursuit

Ecological connections

Field CricketHunts
Actively hunts these common insects on the ground.
Tree frogEats
Wandering spiders have been seen eating frogs in Brazil, and field records include tree frogs.
Common OpossumEaten by
Nocturnal opossums may prey on these spiders.

Safety

Danger 5/5 · Extreme

Avoid touching or approaching this spider in the wild. Always seek help if bitten.

Traits

Collections

Insects

Classification

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

Also known as

Aranha-armadeira · Phoneutria · Armed Spider · Banana Spider

Sources for these Brazilian wandering spider facts

53 studies and references · checked Oct 16, 2026

Frequently Asked Questions

How to identify Brazilian Wandering Spider?

Compare body proportions, leg shape, abdomen markings and the web, if there is one. Eye arrangement can be decisive but rarely shows up in a casual phone photo. A web is a supporting clue, not proof of who built it. Spider Identifier: upload a photo and compare the visible details.

How big is Brazilian Wandering Spider?

17-48 mm

How long does Brazilian Wandering Spider live?

365-2190 days

What does Brazilian Wandering Spider eat?

A nocturnal hunter, it eats insects and small creatures it finds on the forest floor.

Where is Brazilian Wandering Spider usually found?

Rainforest

How does Brazilian Wandering Spider hunt?

Pursuit

How many legs does Brazilian Wandering Spider have?

Is the Brazilian wandering spider dangerous?

Its venom is medically important, but bites are uncommon and most are mild. In one Brazilian study of 422 patients, about 90% had only pain and swelling around the bite and 0.5% had severe symptoms, all young children. Across the Amazon, too, spider bites are painful but rarely life-threatening. Anyone who is bitten should see a doctor.

What should you do if a Brazilian wandering spider bites someone?

Wash the bite, tell an adult and go to the nearest doctor or hospital. Warm compresses can ease the pain. Don’t use home remedies, and only take a photo of the spider if it is safe.

Is there an antivenom for Brazilian wandering spider bites?

Yes. Brazil’s anti-arachnid antivenom, made at the Instituto Butantan, covers Phoneutria. It is free in public hospitals and used only for moderate or severe cases, about 2–3% of patients.

Do Brazilian wandering spiders hide in bananas?

In banana plantations they sometimes shelter in bunches of bananas, and a few have travelled abroad in fruit, for example to Germany and the UK. But this is rare: most big spiders found in imported bananas are harmless look-alikes, and the name “banana spider” is used for several unrelated spiders too.

Is the Brazilian wandering spider the most venomous spider in the world?

Guinness World Records shares its “most venomous spiders” title between Phoneutria and Australian funnel-web spiders, based on lab tests in mice. Experts often rate funnel-webs as the most dangerous to people.

Where do Brazilian wandering spiders live?

The 9 Phoneutria species live from Guatemala in Central America to northern Argentina. P. nigriventer lives mainly in Brazil’s Atlantic Forest but also in plantations, gardens and towns.

How big is a Brazilian wandering spider?

Its body is 1.7–4.8 cm long, and with its legs stretched out it can measure up to 18 cm across.

What does the name Phoneutria mean?

It comes from an ancient Greek word for “murderess”. In Brazil the spider is called aranha-armadeira, the “armed spider”. Despite the dramatic names, most bites are mild.

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