Subscribe Now! National Geographic Magazine $15
Visit our Online Shops

Sign up for free

Newsletters

Once a month
get new photos
and expert tips.

Black Widow Spider
Latrodectus hesperus

Photo: Female black widow spider on a leaf
A female black widow spider on a leaf
Photograph by George Grall

Black Widow Spider Profile

Black widows are notorious spiders identified by the colored, hourglass-shaped mark on their abdomens. Several species answer to the name, and they are found in temperate regions around the world.

This spider's bite is much feared because its venom is reported to be 15 times stronger than a rattlesnake's. In humans, bites produce muscle aches, nausea, and a paralysis of the diaphragm that can make breathing difficult; however, contrary to popular belief, most people who are bitten suffer no serious damage—let alone death. But bites can be fatal—usually to small children, the elderly, or the infirm. Fortunately, fatalities are fairly rare; the spiders are nonaggressive and bite only in self-defense, such as when someone accidentally sits on them.

The animals most at risk from the black widow's bite are insects—and male black widow spiders. Females sometimes kill and eat their counterparts after mating in a macabre behavior that gave the insect its name. Black widows are solitary year-round except during this violent mating ritual.

These spiders spin large webs in which females suspend a cocoon with hundreds of eggs. Spiderlings disperse soon after they leave their eggs, but the web remains. Black widow spiders also use their webs to ensnare their prey, which consists of flies, mosquitoes, grasshoppers, beetles, and caterpillars. Black widows are comb-footed spiders, which means they have bristles on their hind legs that they use to cover their prey with silk once it has been trapped.

To feed, black widows puncture their insect prey with their fangs and administer digestive enzymes to the corpses. By using these enzymes, and their gnashing fangs, the spiders liquefy their prey's bodies and suck up the resulting fluid.

Fast Facts

Type: Bug
Diet: Carnivore
Average lifespan in the wild: 1 to 3 years
Size: 1.5 in (38 mm) long, 0.25 in (6.4 mm) in diameter
Weight: .035 ounce (1 gram)
Did you know? Black widow spiders are considered the most venomous spiders in North America.
Size relative to a paper clip:
Illustration of the animal's relative size

Multimedia

Spider Features

Photo: Spiderweb

Deadly Silk

Discover the amazing strength and complexity of spiderwebs in this feature.

Photo: Tarantula

Photo of the Day: Along Came a Spider

See a photo of a black tarantula enjoying a meal in Portal, Arizona.

Photo: Tarantula

Tarantulas!

Dig down into the secret realm of tarantulas in this interactive feature.

Other Venomous Animals

Map: Locator map for the black widow spider
 Black Widow Spider range

Special Advertising Sections

Photo: Reflection on Yellowstoen Lake, Yellowstone National park

Photo Contest

Share your shots and you could win a trip to the Grand Canyon!

Photo: Valero train

Interactive Map

Explore unique solutions to the world’s biggest challenges.

Bugs Right Rail

Get the Latest Headlines

Photo: Three-horned chameleon

Make us your online news source.

Get Animal Pictures

Photo: Honeybee on a flower

Get your daily dose of photos.

For Kids!

Photo: A cartoon dog

It's no stretch to find fun facts on our Kids site!

Six Degrees Book and DVD

Image: Six Degrees DVD and book

Get an eye-opening warning of the dangers of climate change, one degree at a time.