The black widow spider is the most venomous spider in North America, and lives in temperate regions such as the United States, Australia and Europe. The female spider is approximately 1.5 inches in length when mature, and features a red hourglass shape on the underside of its abdomen. Male black widows are about half the size of females, and feature orange or brown markings on their leg joints. Male black widows have red or pink-colored markings on their backs.
Black widows are nocturnal, solitary spiders that engage in social activity only when mating. Black widow spiders have stiff hairs along their fourth set of legs that help them capture prey, and the spiders tend to live in dark, undisturbed areas. Black widow webs are typically asymmetrical, causing the webs to have a messy, disordered appearance.
After capturing prey in a web, a black widow spider injects its prey with venom and allows the prey to liquefy before consuming it. Some species of black widows survive for several months up to a year without eating. The female black widow occasionally consumes the male widow after mating to provide nutrients to the developing eggs, and can become aggressive when protecting egg sacs.