Phoneutria depilata

Physical description and identification

The Norwegian entomologist Embrik Strand named this spider in 1909, originally as Ctenus depilatus. The 2001 revision of the genus then folded the name into Phoneutria boliviensis as a junior synonym, and there it stayed until a 2021 study combining DNA sequences with genital morphology showed that the populations of Central America and the land west of the Andes form a separate species and restored Strand's name. That change raised the number of recognised Brazilian wandering spiders from eight to nine.

Adults

• Size: body length is roughly 25–40 mm, with females larger than males. The often-quoted figure of 10 cm is the leg span, not the body — a distinction worth making, because it is the source of a lot of exaggeration about this spider.
• Colour: brown overall, with darker longitudinal striping on the dorsal abdomen and a patterned underside. The pattern on the ventral abdomen is one of the features specialists use to separate the species from its relatives.
• Eyes: eight, in the ctenid 2-4-2 arrangement — two small eyes low in front, a row of four above them and two set back at the sides.
• Distinctive features: long legs with paired spines on the underside, used to pin struggling prey, and a dense covering of short hairs. Mature males are slimmer and longer-legged, with swollen palps.
• Threat posture: the family signature. A cornered spider rears back on its hind legs, raises the first two pairs of legs high and spread, and holds the pose while it sways. It is a warning aimed at predators, and the spider retreats if given room.

Eggs and egg sacs

A mated female builds a flattened silk egg sac inside a rolled leaf or crevice and guards it until the young emerge, striking at anything that approaches. Colombian field studies of this species record up to four sacs per female over a season, incubation of about 28 to 34 days, and a total of roughly 430 to 1,300 spiderlings.

Spiderlings

The young leave the sac as pale miniatures of the adults, already able to perform the raised-leg display, and scatter within days. They grow through a long series of moults and reach maturity in about a year, with adults living one to two years in total.

Hunting instead of a web

No capture web is built. Silk goes into a dragline, a thin retreat lining and the egg sac. By day the spider rests inside a rolled banana or heliconia leaf, under bark or in litter; after dark it walks the ground and low vegetation, locating prey by touch and vibration and seizing it in a fast rush. Dietary studies show a menu dominated by insects — crickets, katydids, cockroaches and beetles — along with other spiders. Small frogs and lizards are taken occasionally, but the old claim that the species lives on amphibians, mice and reptiles badly overstates the vertebrate share.

Where Phoneutria depilata lives

Phoneutria depilata occupies Central America and the trans-Andean lowlands of northern South America: Honduras, Nicaragua, Costa Rica and Panama, continuing into northern and western Colombia and northwestern Ecuador. The Andes are the boundary: everything east of the range belongs to P. boliviensis. Older sources that describe the species as simply Central American are only half right, and older records of P. boliviensis from Costa Rica or Panama in fact refer to this spider.

It uses humid tropical forest, seasonally dry forest, forest edges, secondary growth and — very commonly — banana, plantain and coffee plantations. The rolled leaves of banana and heliconia make ideal daytime retreats, which is exactly why this is one of the species that turns up in harvested fruit. Around villages it shelters in woodpiles, sheds, boots and stored produce.

Is Phoneutria depilata venomous?

Yes, and the answer matters: this is a member of a genus whose venom is treated as medically significant. The venom carries the same broad families of neurotoxic peptides found across Phoneutria, the PhTx fractions that act on voltage-gated sodium and calcium channels in nerve endings, producing pain out of proportion to the size of the wound.

It sits at the mild end of the genus. Comparative studies place its venom well below that of P. nigriventer, and the cases reported from Colombia and Central America are dominated by local pain and swelling rather than the whole-body envenomation syndrome the larger species can cause. Across the genus, Brazilian hospital series find roughly nine in ten wandering spider bites produce local symptoms alone, under one in ten cause systemic signs, and well below one per cent are severe, almost entirely in small children. No confirmed human death has been attributed to P. depilata. The antiarachnid serum made by the Instituto Butantan in Brazil covers Phoneutria envenomation but is rarely called for here. Our list of the most venomous spiders sets the genus against the rest.

Bites: symptoms, timeline and what to do

Bites are defensive and happen when the spider is pressed against skin — a hand into a bunch of bananas or a woodpile, a foot into a boot, a body against a spider that has walked into bedding. Harvesters and farm workers account for a disproportionate share of cases for exactly that reason.

Typical timeline. Pain is immediate, often burning, and may radiate a short way up the limb, with redness and swelling around the puncture over the following minutes to hours. In most cases nothing more develops and the pain settles within a day. A minority of patients report sweating, nausea or vomiting, a racing heartbeat, tremor and agitation, usually within the first hours. Severe envenomation is rare and would be expected mainly in a young child; the prolonged painful erection (priapism) seen in serious P. nigriventer cases is not a typical feature of bites by this species.

What to do. Wash the site with soap and water, keep the person calm and the limb still, and go to a clinic or hospital for assessment — immediately if the patient is a child, is pregnant, or develops any symptom away from the bite. A cold pack over a cloth eases the local swelling on the way. Photograph the spider or bring it safely contained, because the identification changes what the clinician watches for. Never apply a tourniquet, cut or suck the wound, or give alcohol, and do not wait at home to see what happens.

Ecological importance and behavior of Phoneutria depilata

This is a solitary, nocturnal, free-running predator that hunts on foot, and in plantation landscapes it removes large numbers of crickets, cockroaches and beetles that a web would never intercept. It is prey as well as predator, and that two-way role is where its ecological value lies.

Natural predators: spider wasps paralyse adults to provision their nests, while birds, opossums and other small mammals, lizards, snakes and larger spiders take them opportunistically. Ants and parasitoid wasps attack egg sacs, which is why the female stays with hers.

Prey-predator dynamics: speed, the threat display and the venom are all defences against those animals rather than weapons aimed at people. Venom is metabolically expensive, and many defensive bites deliver little or none of it, which helps explain why so many recorded bites amount to local pain alone.

Reproduction and season: courtship involves the male signalling by drumming and vibrating before he approaches. Females mate more than once and produce a series of egg sacs; in the more seasonal parts of the range, activity and encounters peak in the wetter months.

Relationship with humans: mostly quiet coexistence, with a real but manageable risk for people who handle vegetation and fruit. Gloves during harvesting, a torch on paths after dark and a shake of the boots in the morning remove most of it.

Similar spiders and how to tell them apart

Quick facts

Did you know?

• Strand described more than 2,000 animal species. This one was swallowed by P. boliviensis in the 2001 revision of the genus and spent two decades as a synonym before his name was restored in 2021.
• The species is unusually well studied for a Neotropical spider: its reproductive behaviour, growth and diet were all documented in Colombia — under the name P. boliviensis, which is why the literature can be confusing.
• Rolled banana and heliconia leaves are such reliable daytime retreats that researchers survey for the species simply by unrolling them at midday.
• Of the nine Phoneutria species, only a minority cause serious envenomation; this one shares the frightening common names without the matching record.

In summary, Phoneutria depilata is a large, fast, genuinely venomous hunter whose bite is painful but rarely dangerous. Treat it with respect, keep hands out of banana crowns and woodpiles, get any bite checked by a doctor — and ignore the claim that it is four inches across the body.