Black Widow Spider
Latrodectus mactans
Quick answer
The black widow is a venomous spider recognized by the shiny black body and red hourglass mark on the underside of the female's abdomen. Its venom is a potent neurotoxin, but bites are rarely fatal to healthy adults and antivenom is available. Found in sheltered, dark places across North America, females are far larger and more dangerous than males and usually live 1 to 3 years.
Black Widow Spider facts at a glance
| Scientific name | Latrodectus mactans |
|---|---|
| Diet | Carnivore (insects and other small arthropods) |
| Habitat | Sheltered, dark spots in fields, sheds, and woodpiles |
| Lifespan | 1–3 years (females; males much shorter) |
| Size | Female body about 1.3 cm (0.5 in); legs wider |
| Venom | Potent neurotoxin; bites rarely fatal with care |
| Conservation status | Least Concern (IUCN) |
| Kingdom | Animalia |
|---|---|
| Phylum | Arthropoda |
| Class | Arachnida |
| Order | Araneae |
| Family | Theridiidae |
| Genus | Latrodectus |
Where it lives
Sheltered, dark places across North America, especially the southern and western United States.
Appearance and identification
The female black widow is glossy black with a distinctive red hourglass mark on the underside of her rounded abdomen. Males are much smaller, lighter in color, and usually harmless to people. The bold markings serve as a warning of the spider's potent venom.
Venom and bites
Black widow venom contains a powerful neurotoxin that can cause muscle pain, cramps, sweating, and nausea, a condition sometimes called latrodectism. Despite a fearsome reputation, bites are rarely fatal to healthy adults, and deaths are very uncommon where medical care and antivenom are available. The spiders are not aggressive and usually bite only when trapped against the skin.
Web and hunting
Black widows build strong, irregular, tangled webs in sheltered, dark places such as woodpiles, sheds, and rock crevices. They hang upside down in the web and wait for insects to become ensnared, then wrap and bite their prey. The silk is notably tough, helping hold struggling insects until the venom takes effect.
Reproduction and the name
The black widow gets its name from the belief that females eat the males after mating, though in the wild this happens far less often than once thought. Females produce silk egg sacs that can hold hundreds of eggs, guarding them until the spiderlings hatch. The young disperse on strands of silk carried by the wind in a behavior called ballooning.
Frequently asked questions about the Black Widow Spider
How dangerous is a black widow bite?
A black widow bite injects a potent neurotoxin that can cause pain, cramps, and other symptoms, but it is rarely fatal to healthy adults. With medical care and antivenom, serious outcomes are very uncommon.
How do you identify a black widow?
Female black widows are glossy black with a red hourglass mark on the underside of the abdomen. Males are much smaller and lighter and are generally harmless to people.
Do black widows really eat their mates?
The name comes from cases where the female eats the male after mating, but in the wild this is much rarer than the legend suggests. It happens more often in confined laboratory settings.
What do black widow spiders eat?
Black widows are carnivores that eat insects and other small arthropods caught in their webs. They wrap prey in silk and use venom to subdue it before feeding.
Where do black widow spiders live?
Black widows favor sheltered, dark places such as woodpiles, sheds, garages, and rock crevices across North America. They build tangled webs and tend to stay hidden.
Are black widows aggressive?
No. Black widows are shy and not aggressive, biting mainly in self-defense when pressed against skin. Most bites happen accidentally when people reach into hidden spaces.
