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Venomous spiders: the four that genuinely matter

Thousands of spider species are venomous and almost none can hurt a person. Four groups account for essentially all medically significant bites: Australian funnel-webs, widow spiders, recluse spiders, and the Brazilian wandering spider. Antivenom exists for the serious ones, and deaths in countries with functioning emergency care are now very rare.

  • 2High risk
  • 4Medium
  • 1Low
  • 7Zones tracked

What each one does

Funnel-web envenomation is fast and severe and is a medical emergency; pressure immobilisation and hospital, immediately. Widow bites cause intense muscle cramping and sweating that builds over hours. Recluse bites are often painless at first and may develop into a slowly expanding necrotic lesion over days. Wandering spider bites are immediately very painful and can be systemic.

Where bites happen

Not in the wilderness — in sheds, woodpiles, garages, shoes, bedding and stored boxes. Recluse and widow spiders in particular live alongside people in undisturbed, dry, dark places, and bites usually occur when a spider is pressed against skin by clothing or a hand reaching blindly.

How to avoid it

  • Shake out shoes, gloves and clothing that has been on the floor or stored, especially in Australia and the Americas.
  • Wear gloves when moving woodpiles, boxes or garden debris.
  • Check bedding in rural or long-unused accommodation.
  • Do not reach blindly into dark spaces, under eaves or behind stored items.
  • In Australia, never swim past or pick up a funnel-web found in a pool — they survive submersion for hours.

If it happens

  • Funnel-web or wandering spider: pressure immobilisation bandage, keep still, hospital immediately — antivenom is effective.
  • Widow: clean the bite, apply a cold pack, and seek medical care for the cramping; antivenom exists.
  • Recluse: clean and cover, do not apply heat, and have a doctor review the wound over the following days.
  • Photograph the spider if it can be done safely — identification changes the treatment.

General guidance only — not a substitute for medical advice or local emergency services.

Where we track it

7 zones in the Dangers Here hazard database, by danger level.

High

  • Brazil & South America — Wandering Spider
  • Sydney & Eastern Australia — Funnel-web

Medium

  • Africa & Middle East — Sac & Widow Spiders
  • Australia — Mouse & Huntsman Spiders
  • North America — Black Widow & Brown Recluse
  • South America — Recluse Spiders

Low

  • Southern Europe — Mediterranean Black Widow

Questions

Where are venomous spiders a risk?

We track 7 zones for this hazard. 2 are rated high risk, including Brazil & South America — Wandering Spider, Sydney & Eastern Australia — Funnel-web. 4 are rated medium and 1 low.

How do you avoid venomous spiders?

Shake out shoes, gloves and clothing that has been on the floor or stored, especially in Australia and the Americas. Wear gloves when moving woodpiles, boxes or garden debris. Check bedding in rural or long-unused accommodation.

What is the first aid for venomous spiders?

Funnel-web or wandering spider: pressure immobilisation bandage, keep still, hospital immediately — antivenom is effective. Widow: clean the bite, apply a cold pack, and seek medical care for the cramping; antivenom exists. Recluse: clean and cover, do not apply heat, and have a doctor review the wound over the following days.

What each one does

Funnel-web envenomation is fast and severe and is a medical emergency; pressure immobilisation and hospital, immediately. Widow bites cause intense muscle cramping and sweating that builds over hours. Recluse bites are often painless at first and may develop into a slowly expanding necrotic lesion over days. Wandering spider bites are immediately very painful and can be systemic.

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