The Black Widow Spider Black widows are named for the female's occasional cannibalistic practice towards her mate. Females are easier to identify, and sometimes males aren't even recognized as black widows.
Males are smaller, and lighter in color.
However, females are the only sex able to inflict the painful bite. Luckily they have a red hourglass on their underside, which is made visible by the female's habit of hanging upside down from her web. Black widow populations are erratic, sometimes rising and falling dramatically over the years. They prefer to make their webs in dark, dry, undisturbed places. They are common underneath houses, in garages, or outside in woodpiles.