Spiders in Uruguay
Uruguay has two groups of spiders that matter medically: the Chilean recluse, Loxosceles laeta, which lives inside houses and causes the country's most serious bites, and the native widows Latrodectus mirabilis and L. corallinus of open grassland. Brazilian wandering spiders reach only the warm north and are rare there. Everything else on this page — the tarantulas, the big orb-weavers, the jumping spiders and the southern house spider — is harmless.
On this page
- What spiders live in Uruguay?
- Which Uruguayan spiders are actually dangerous?
- Where you meet them in Uruguay
- Spider season in Uruguay
- Look-alikes and names that mislead
- Common Spiders in Uruguay
- Biggest Spiders in Uruguay
- Most Venomous Spiders in Uruguay
- Less Venomous Spiders in Uruguay
- Living with Uruguay's spiders
- Frequently asked questions
What spiders live in Uruguay?
Uruguay is small and temperate and has no rainforest, whatever the travel copy says. Almost all of it is campos — rolling pampa grassland — broken by gallery forest, palm savanna, rocky sierras and coastal dunes. The fauna is Pampean rather than Amazonian: the country sits at the southern edge of many Brazilian ranges, so several famous South American spiders occur here only as a thin northern fringe.
Web-builders are the visible half. Big wheel webs in gardens and gallery forest belong to the orb-weavers: the silvery Argiope argentata with its zigzag hub ribbon, the banded garden spider, the spiny spinybacked orbweaver strung across paths, and in the warm north the golden silk orb-weaver. Tangle webs in wall corners belong to cobweb spiders — the common house spider, the triangulate cobweb spider and the red house spider — and cellar spiders hang in every bathroom.
The hunters are harder to see. Uruguay has a rich wolf spider fauna, including Schizocosa malitiosa and the red-jawed Lycosa erythrognatha, plus jumping spiders from the grey gray wall jumping spider to the translucent green Lyssomanes. The spitting spider Scytodes globula hunts other spiders indoors, the southern house spider spins radiating lace over brickwork, and Grammostola tarantulas — the Uruguay black beauty among them — burrow in the sierras.
Which Uruguayan spiders are actually dangerous?
The recluse — the one that matters
The Chilean recluse, Loxosceles laeta, known regionally as araña de rincón, causes Uruguay's most serious bites. It is a small, uniformly tan sicariid with long thin legs, a faint violin mark and six eyes in three pairs rather than eight, and crucially it lives inside houses: behind wardrobes and pictures, in stored clothing and boxes, under beds that are rarely moved. Most bites happen at night in bed or while dressing.
Loxoscelism develops slowly. The bite is often painless at first; over six to twelve hours it becomes a burning, mottled red-white-and-blue lesion that may form a dark eschar and an ulcer taking weeks to heal. A minority of cases — more frequent with L. laeta than other recluses — turn systemic within a day or two, with fever, haemolysis and kidney injury, which can be life-threatening in children. Any suspected bite needs same-day hospital assessment.
The widows
Uruguay's native widows are Latrodectus mirabilis and Latrodectus corallinus, spiders of grassland, fence lines and stone piles rather than houses; the introduced brown widow occurs around coastal towns and is milder. Their bite causes latrodectism: cramping pain spreading to the abdomen, back and thighs within an hour, with sweating and nausea. It is painful, treatable and rarely dangerous to a healthy adult.
The wandering spider, in proportion
The Brazilian wandering spider genus Phoneutria deserves its reputation in Brazil, but Uruguay is at the southern limit of its range: Phoneutria nigriventer occurs only in the warm north and is genuinely rare there. Nor is it "aggressive" — the raised-front-legs display is a defensive threat, and it bites when cornered or trapped in clothing. Bites are medically significant and need emergency care.
Everything else is harmless. The false black widow, Steatoda grossa, is most often mistaken for a real widow and its bite is minor; Grammostola tarantulas are famously placid; and the southern house spider, orb-weavers, jumping spiders and wolf spiders all lack medically important venom. See the most venomous spiders for context.
Bitten? Wash with soap and water, apply a cold pack, keep the limb still and photograph the spider if you safely can. Go to a hospital the same day for any suspected recluse bite, and at once if a lesion darkens, cramping pain spreads, or fever, vomiting or dark urine appear. Do not cut, suck, burn or tourniquet the wound.
Where you meet them in Uruguay
Inside the house
This is the habitat worth taking seriously, because the recluse is an indoor spider: wardrobes, stored clothing, boxes, the backs of pictures, undisturbed corners. The rest of the indoor fauna is benign — cellar spiders, cobweb spiders in ceiling angles, the spitting spider hunting them, jumping spiders on window frames. See our guide to house spiders.
Campos, fence lines and stone walls
Native widows live at ground level in grassland: under stones, in tussocks, along fence posts and around abandoned machinery. Wolf spiders hunt the same ground, and tarantulas burrow in the rocky campos of Rivera, Tacuarembó and Lavalleja.
Gallery forest, palms and the coast
Riverine forest and the butiá palm savanna of Rocha hold the largest orb webs and most of the subtropical species, which reach Uruguay along warm northern corridors.
Spider season in Uruguay
Uruguay has four real seasons and spider activity follows them closely. Spiderlings hatch in spring, adult ground hunters become obvious from October, and orb-weavers grow slowly, barely noticeable until midsummer.
The peak runs from December to March: Argiope and golden silk webs reach full size, male tarantulas leave their burrows in search of females — which is when people find them crossing rural roads — and adult male hunters come indoors. Recluse bites are different: the spider lives indoors year-round, so cases happen in winter too, usually when stored clothing or boxes are moved.
Look-alikes and names that mislead
The confusion that costs most is between the recluse and every other small brown spider in the house. Count the eyes in a photograph: Loxosceles has six, in three widely spaced pairs, and long thin legs of uniform colour with no banding or spines. Ordinary brown house spiders have eight eyes, patterned legs and obvious webs.
The second confusion is Steatoda for a widow. False widows are shiny and globular like the genuine article but brown to purplish-black, usually with a pale crescent across the front of the abdomen and no red hourglass beneath. The southern house spider's dark, stout females are regularly mistaken for recluses.
Finally, the tarantulas. The older claim that the golden silk orb-weaver is Uruguay's biggest spider is wrong: by body mass the Grammostola win easily. Uruguay's fauna is essentially shared with Argentina and southern Brazil.
Common Spiders in Uruguay
- Silver Garden Orb Weaver Spider (Argiope argentata)
- Common House Spider (Parasteatoda tepidariorum)
- Long-bodied Cellar Spider (Pholcus phalangioides)
Biggest Spiders in Uruguay
- Golden Silk Orb Weaver Spider (Trichonephila clavipes)
- Southern House Spider (Kukulcania hibernalis)
- Silver-sided Sector Spider (Zygiella x-notata)
Most Venomous Spiders in Uruguay
Sicariidae Spiders
Cobweb Spiders/Tangle Web Spiders (Theridiidae)
Cobweb SpidersFalse Black Widow (Steatoda grossa)Identify the false black widow (Steatoda grossa): size, colour, its gumfoot cobweb, how it differs from a true widow, and how bad the bite r
Cobweb SpidersBrown Widow (Latrodectus geometricus)Identify the brown widow (Latrodectus geometricus) by its orange hourglass and spiky egg sac, and learn how its bite compares with a black wWandering Spiders
Less Venomous Spiders in Uruguay
Orb Weavers
Orb WeaversGolden Silk Orb-Weaver (Nephila)Golden silk orb-weavers (Nephila): huge females, tiny males, giant golden webs, where they live, what they eat and whether their bite is dan
Orb WeaversBanded Garden (Argiope trifasciata)Identify the banded garden spider (Argiope trifasciata): silver banding, size, the zigzag in its web, egg sac, range, and whether its bite i
Orb WeaversSpinybacked Orbweaver (Gasteracantha cancriformis)Spinybacked orbweaver (Gasteracantha cancriformis) identification: six abdominal spines, colour forms, the silk-tufted web, range and whetheJumping Spiders
Jumping SpidersGray Wall Jumping (Menemerus bivittatus)Identify the gray wall jumping spider (Menemerus bivittatus): size, the flattened grey-haired body, its walls-and-tree-trunks habitat, and w
Jumping SpidersLyssomanesA guide to Lyssomanes, the translucent green jumping spiders of the Americas: how to identify them, where they live, what they hunt and whetCobweb Spiders/Tangle Web Spiders (Theridiidae)
Cobweb SpidersRed House (Nesticodes rufipes)Identify the red house spider (Nesticodes rufipes): rusty red body, tangled indoor web, why it is mistaken for a widow, and what its bite ac
Cobweb SpidersTriangulate Cobweb (Steatoda triangulosa)Identify the triangulate cobweb spider (Steatoda triangulosa): the purple zigzag pattern, yellow legs, its tangle web, and whether the bite Crevice Spiders
Tarantulas
Crevice WeaversSouthern House (Kukulcania hibernalis)Identify the southern house spider (Kukulcania hibernalis): female and male size and color, the sunburst web, range, and why males are mista
TarantulasUruguay Black Beauty Tarantula (Grammostola quirogai)Identify the Uruguay black beauty tarantula (Grammostola quirogai): size, its two colour morphs, burrow, range in Uruguay, and how harmless Living with Uruguay's spiders
Spraying achieves very little against recluses and kills the harmless predators that keep flies and mosquitoes down. Physical habits work far better.
- Shake out stored clothes, towels and bedding and check shoes before putting them on — that is how most recluse bites are avoided.
- Pull furniture away from walls when you clean, and vacuum behind wardrobes, headboards and picture frames.
- Store clothing in sealed plastic rather than cardboard, and keep beds off the wall.
- Wear gloves for stone piles, fence lines and old machinery in the campo — widow habitat.
- Move harmless indoor spiders outside with a glass and a card; cellar and spitting spiders prey on recluses.
Frequently asked questions
Are there medically significant venomous spiders in Uruguay?
Yes, two groups. The Chilean recluse, Loxosceles laeta, causes the country's most serious bites and lives inside houses. The native widows Latrodectus mirabilis and L. corallinus, of open grassland, cause painful but rarely dangerous latrodectism. Brazilian wandering spiders reach only the far north and are rare. Everything else is harmless.
What is the most dangerous spider in Uruguay?
The Chilean recluse, known locally as araña de rincón. Its bite is often painless at first, then develops over hours into a burning, discoloured lesion that can ulcerate. A minority of cases turn systemic within a day or two, with fever, haemolysis and kidney injury, which is why any suspected bite needs same-day hospital assessment.
Are wandering spiders in Uruguay dangerous to humans?
Phoneutria nigriventer has medically significant venom, but in Uruguay it occurs only in the warm north and is genuinely rare. It is defensive rather than aggressive and bites when cornered or trapped in clothing. A confirmed bite is an emergency, yet most Uruguayans will never encounter this spider at all.
What is the largest spider found in Uruguay?
A tarantula. Grammostola species of the sierras and rocky campos, including the Uruguay black beauty, Grammostola quirogai, are by far the heaviest spiders in the country. They are slow, docile burrowers whose venom is medically insignificant; their defence is a cloud of irritating abdominal hairs rather than a bite.
What are the most common spiders inside Uruguayan homes?
Long-bodied cellar spiders in bathrooms and garages, the common house spider and triangulate cobweb spider in ceiling corners, the small orange red house spider, jumping spiders on window frames and the spitting spider Scytodes globula hunting them. All are harmless. The one indoor species that matters medically is the recluse.
Does Uruguay have rainforest spiders?
No, because Uruguay has no rainforest. The country is temperate grassland with gallery forest along rivers, palm savanna in Rocha and coastal dunes. Subtropical species reach Uruguay only as a thin northern fringe along the warm river corridors, which is why famous Brazilian spiders are scarce or absent here.
How do you identify a silver garden orb-weaver in Uruguay?
Look for a bright silvery carapace and abdomen marked with black and yellow, and for the spider sitting head-down at the centre of a large orb web with its legs paired into an X. Argiope argentata usually adds a conspicuous white zigzag ribbon, a stabilimentum, across the hub.
Is the southern house spider harmful in Uruguay?
No. Kukulcania hibernalis is not medically significant. Females are dark, stout and long-lived and spin a flat, radiating lace web over cracks in old brickwork; males are slimmer and wander. They hide rather than confront, and they are frequently misidentified as recluses or small tarantulas because of their size and colour.
How can you tell a recluse from an ordinary house spider?
Count the eyes in a photograph. Recluses have six eyes in three separated pairs, while nearly all other house spiders have eight. Recluse legs are long, thin and uniformly tan with no bands or strong spines, and the spider builds only an untidy retreat sheet rather than a structured web.
When are spiders most active in Uruguay?
From December to March. Orb-weaver webs reach full size, male tarantulas wander in search of females and are found crossing rural roads, and adult male hunters come indoors. Recluses are a year-round indoor presence, so bites also happen in winter when stored clothing, boxes or furniture are moved.
Published December 2, 2023 · Last updated September 14, 2026