Female Black Widow Spider Facts and Information

The female black widow spider has a reputation for its cannibalistic behavior. For years the story has been spread that females consume their mates following copulation. While mate predation does occur, many males survive the encounter and may mate multiple times.

Female black widows are considered a medically threatening spider due to their potent neurotoxic venom which affects the nervous system. Bites can occur when a person unwittingly crushes the spider when picking objects that a widow has chosen as home. While the bite is unpleasant, it is not fatal to the average person. However, if bitten by a widow, it is important to contact a medical professional.

Female black widow spiders can be very aggressive when protecting their egg sacs. Female black widow spiders typically survive between one and three years.

The female black widow spider's body averages 3 to 10 mm in size. They have long, slender legs and round abdomens. On the underside of the abdomen is their characteristic red, hourglass-shaped marking. Females tend to hang upside down from their webs. This serves to exhibit the hourglass marking in warning.

Female rarely leave their webs, which are irregularly shaped and found at ground level. They guard their egg sacs until they hatch, at which point they exhibit very little parental involvement. Eggs are most commonly produced in autumn. Each egg sac can contain several hundred eggs.