Do Black Widow Spiders Bite? Are They Dangerous?
Short answer: the black widow spider can cause medically significant bites, stings or disease. Females have venom that can cause severe muscle pain and cramps; seek medical care after a bite.
Risk rating: Health risk
Females have venom that can cause severe muscle pain and cramps; seek medical care after a bite.
Are black widow spiders dangerous to humans?
Females have venom that can cause severe muscle pain and cramps; seek medical care after a bite.
On our four-level scale, the black widow spider is rated health risk, meaning it can cause medically significant bites, stings or disease. Black Widow Spiders can bite, so it is worth handling them with care.
Are they dangerous to pets?
Black Widow Spiders can bite or sting curious pets that paw at them or try to eat them. Watch for swelling, drooling or limping, and call your veterinarian right away if your pet has trouble breathing or a large reaction.
Can they damage your home or garden?
Black Widow Spiders don't damage homes, but their presence indoors is a safety concern.
What to do if you are bitten
- Wash the area with soap and water.
- Apply a cool compress to reduce swelling.
- Use an over-the-counter antihistamine or hydrocortisone cream for itching, following the label.
- Avoid scratching, which can lead to infection.
Call 911 right away if someone has trouble breathing, swelling of the face or throat, dizziness or a racing heartbeat after a bite or sting.
Females have venom that can cause severe muscle pain and cramps; seek medical care after a bite.
How to identify black widow spiders
A shiny black spider with a red hourglass on the underside of its round abdomen. It builds messy, tangled webs in woodpiles, sheds, meter boxes and outdoor furniture.
- Glossy black, globe-shaped abdomen
- Red or orange hourglass marking underneath
- Irregular, strong tangled web close to the ground
| Scientific name | Latrodectus mactans |
|---|---|
| Group | Spiders |
| Size | 3–13 mm (up to about 0.51 in) |
| Colors | Black and Red |
| Legs | 8 legs |
| Wings | No (as usually seen) |
| Where found | Basement or garage, Yard or patio and Woods or trails |
| Most active | Spring, Summer, Fall and Winter |
| Bites | Yes |
| Stings | No |
| Risk level | Health risk |
When you'll see black widow spiders
Black Widow Spiders are most active in spring, summer, fall and winter. In spring, overwintering adults become active and many species lay their first eggs. Summer heat speeds up development, so populations can grow quickly. In fall, many bugs look for shelter, and some move toward or into buildings. In winter, activity continues mainly indoors in heated spaces.
Typical places to check: basement or garage, yard or patio and woods or trails.
About spiders
The black widow spider is one of the spiders. Spiders have eight legs, two main body sections and no antennae. Almost all spiders have venom to subdue prey, but only a few have venom that matters to people. Many build webs, while others, such as wolf spiders and jumping spiders, hunt on foot.
Spiders go where their food is. A home with lots of spiders usually has plenty of other insects, so general pest control reduces spiders too.
How to avoid problems with black widow spiders
- Wear gloves when moving firewood, boxes and outdoor items
- Clear clutter from garages, sheds and crawl spaces
- Remove webs and egg sacs with a vacuum or long tool
Frequently asked questions
Do black widow spiders bite?
Yes. Females have venom that can cause severe muscle pain and cramps; seek medical care after a bite.
Do black widow spiders sting?
No, black widow spiders do not sting.
Are black widow spiders poisonous?
The black widow spider can cause medically significant bites, stings or disease. Females have venom that can cause severe muscle pain and cramps; seek medical care after a bite.
Where do black widow spiders live?
Black Widow Spiders are usually found in basements and garages, in yards and on patios and in woods and along trails, and are most active in spring, summer, fall and winter.