Black widow spiders have a reputation for being dangerous due to their venom, although only adult females have large enough fangs to penetrate human skin. While anyone bitten should seek medical attention immediately, it is extremely rare for a black widow's bite to be life-threatening. History: Black widow spiders are quite widespread, and their bites can cause abdominal cramps, muscle pain, and spasms. While the bite can be dangerous, deaths are extremely rare and many people experience little to no adverse symptoms whatsoever. Scientific Name: Genus Latrodectus, specifically L. mactans or L. hesperus. Characteristics: These spiders are identified by their long, thin legs and large, round abdomen. Despite the black widow being venomous, these Good Luck Minis® won't cause you any harm! Size: From leg tip to leg tip, these Good Luck Minis® are 1" long. They are entirely black, except for the characteristic red hourglass mark on the underside of their abdomen.