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Black Widow Spider

Latrodectus mactans

Venomous / dangerousUncommon

Quick answer

Venomous bite. Keep your distance. Safety level: Venomous / dangerous.

How to identify the Black Widow Spider

Adult females are glossy black with a round, shiny abdomen and a red or orange hourglass shape on the underside.
Males and young spiders are smaller and paler, often brown or grey with red, white or yellow marks.
It builds a messy, tangled web low to the ground, usually in a dark, sheltered corner.
Size: 8–13 mm.

Where it lives

Black widows and their close relatives live in warm regions of the Americas, Africa, the Middle East, Asia and Australia. They hide in woodpiles, garages, sheds, under outdoor furniture, in meter boxes and among stored items.

Is it dangerous?

The black widow is venomous and its bite is medically important. It bites only when pressed against skin, for example when someone puts on a glove or shoe where it is hiding. The bite may feel like a pinprick, followed within an hour by spreading pain, muscle cramps (especially in the belly, back or chest), sweating and nausea. Children, older adults and people with heart conditions are at higher risk. Deaths are rare with medical care.

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Children and pets

Keep children and pets well away.

What to do

Don't touch it or try to catch it by hand.
Wear gloves when cleaning garages and woodpiles.
Get medical help right away after a bite.

Fun fact

Look for the red hourglass shape on the underside of its belly.

⚠ Call emergency services straight away for trouble breathing, swelling of the face or throat, or a scorpion sting in a child. This page is general information, not medical advice.

Frequently asked questions

What should I do after a black widow bite?

Stay calm, wash the bite with soap and water, apply a cold pack and get medical help right away. Call your local poison centre or emergency number.

Is a black widow bite always dangerous?

Not always: some bites inject little venom. You cannot tell at home, so any suspected bite should be checked by a doctor.

How do I keep black widows away?

Wear gloves when moving wood or stored boxes, shake out shoes kept outside, and clear clutter from garages and sheds.