Black Widow Spiders


The female southern black widow is a shiny, jet-black spider that is about 1-1.5 inches long when including the length of its legs. The male is black, has white underbody markings with red spots, and is only ½ to 1-inch long, including its legs. The female has the familiar reddish colored hourglass marking on the underside of her abdomen. Immature stages of the female black widow may have a white-colored hourglass or in some instances the hourglass is entirely absent.


Black widows are often thought of as being super aggressive and very dangerous, thanks in part to movies that depict them as cruel, cunning monsters just lurking about looking for someone to kill. But, in general, these spiders live inconspicuously where people and pets may frequent and are rarely responsible for causing problems. However, black widow spiders will unquestionably defend themselves and may even mistake a person or pet that touches their web as prey that will become the spider’s next meal.

Black widow venom is a potent neurotoxin, and while the vast majority of people that are bitten have no serious consequences other than pain, discomfort, muscle cramping, and swelling, cats are extremely affected by the venom and may die as the result of a black widow bite without veterinarian care.


Black widow spiders prey on both living and dead insects, spiders, and other kinds of small insect-like creatures that get trapped in their webs. When prey gets into the web, the female will move to the part of the web that contains the prey, bite, and inject venom. The spider’s venom paralyzes the prey and breaks down bodily tissue that the spider feeds upon as it sucks out the digested, liquefied remains.


Black widows are found in protected habitats such as under rocks, in stumps and piles of wood, abandoned rodent burrows, under bushes, in barns and garages, and other hidden areas that remain undisturbed.


After mating, the female spider will produce from 5-10 eggs cases, each of which may contain from 200-800 eggs. About eight days after laying the egg cases, young spiderlings hatch, but continue to live in the egg case for about nine more days, after which time the young begin to move about. The young spiders usually disperse quickly, using a procedure known as ballooning. This method of dispersal begins with the young elevating their abdomen and producing silk that gets caught up by the wind that carries spiderlings to other places.


Evidence of black widow spiders includes their webs and observing them in their preferred habitats.


Things that are useful in preventing black widow spiders include:

  • Keeping the areas that make up their preferred habitat clean and free of debris or thick vegetation that attracts and protects them.
  • Keeping the inside of buildings and homes clean, free of clutter, and keeping the number of insects and other spiders to a minimum since black widows won’t stick around very long if they don’t have a reliable source of food. When cleaning, be sure to wear protective clothing, especially gloves.
  • Removing (carefully) spider webs with a vacuum or broom.
  • Placing sticky traps around and near places which spiders might use to get inside.
  • Exchanging fluorescent and conventional incandescent light bulbs with sodium vapor or “bug lights” that will attract fewer insects.
  • Creating an open, exposed band of no vegetation around the home’s perimeter and trimming back shrubs and limbs so they do not touch the side of the house.
  • Sealing any openings in siding or the foundation around pipes or electrical conduit that lead into the home’s interior, plus sealing cracks and gaps around the frame of the entry door into the crawl space.


  • Insect control using insecticide products is one of the more effective ways to control black widow and other spiders. However, always be sure the product’s label is carefully and completely followed.
  • Apply insecticide control products as barrier treatments around the perimeter of the house and potential entry points such as door, garage, and crawl space entrances.
  • Apply liquid or dust formulations to places likely used as inside harborage by spiders.
  • Carefully use an aerosol formulation to directly spray exposed black widows.