The spiderlings may remain in the egg sac for one month before they emerge. Females mature after 6 to 8 molts and males mature after 3 to 6 molts. Upon reaching maturity, males only live about three months while females may live as long as three years. A bite from a black widow delivers a dose of neurotoxin that can cause severe muscle cramping and difficulty breathing. Only a tiny fraction of all bites lead to death, usually in small children and the elderly.
Adult males are much smaller than females and are considered harmless.
Black widows feed on insects, centipedes and other spiders. The Western black widow occurs in the western portion of the United States. It is similar in appearance to the black widow however, its hourglass marking is often divided into two separate spots. Its preferred habitat is a rodent burrow but it can be found in urban settings. Western widows are larger and tend to live longer than their southern relatives.