Only a female's bite is dangerously venomous, and only females have red hourglass shapes on their underbellies. To catch prey, they weave complex asymmetrical webs in out-of-the-way places. After the male inseminates the female black widow, if he does not escape in time, the female sometimes eats him. Black widows are shiny black in color with rounded abdomens. They mainly feed on insects and other spiders, but sometimes they catch and eat lizards, snakes and mice. When prey is caught in the web, they wrap it securely, hold it tight and bite it, injecting the venom. After about 10 minutes, when the prey dies, the spider releases digestive enzymes, which it uses to liquefy it and suck up the fluid.
Black widow females weave cocoons in which they suspend their eggs in their webs. One egg sac may contain 100 to 750 eggs, and a female lays four to nine egg sacs in a summer. When the baby spiders hatch after 20 to 30 days, most of them die due to lack of food, lack of shelter or cannibalism. The spiders that survive mature into adults within 6 to 9 months.Learn more about Spiders