Black Widow Spiders

One Dangerous Spider

Black Widow

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Unlike most spiders that are harmless, the black widow spider is one of three venomous spiders commonly found in some parts of the United States. The black widow is found throughout North America but is most common in the southern and western areas. The other two common venomous spiders are:

  • Brown recluse—most commonly found in the Midwestern and southern states.
  • Hobo spiders—found throughout the Pacific Northwest.

Black Widow Identification

What it looks like:

  • Body: the female is about 1/2-inch long; males are about half as long.
  • Coloring: shiny black with distinguishing mark noted below.
  • Distinguishing marks: The red hour-glass marking on the underside of the black widow's abdomen is its most distinguishing characteristic and is a familiar mark of this feared spider. However, this marking may also be yellowish and be visible as only a spot

Where it is found:

  • Prevalent throughout the United, most commonly in the south and the west.
  • Black widow spiders seek shelter in out-of-the-way, undisturbed areas.
  • Outdoors in woodpiles and areas of accumulated debris or rubble; in hollow stumps and rodent burrows; in sheds, garages, and outhouses; and even in porch furniture.
  • Indoors in cluttered areas, particularly in basements and crawl spaces.

What it does:

  • The black widow builds its irregularly shaped, tangled web between objects, under rocks and logs, along embankments or in outbuildings. If disturbed, the spider can hide in a tiny funnel of the web.
  • This spider's longish legs enable it to scurry quickly. See video.
  • The most common cause of human bites is when a person inadvertently contacts the black widow spider web.
  • This spider feeds on insects caught in its web as well as lizards and small snakes.

The Black Widow Spider Bite

  • Black widow spiders are not aggressive toward humans, preferring to flee rather than fight. But they will bite if provoked or in defense.
  • The bite of this spider is fairly easily distinguished because it leaves two puncture marks in the skin.
  • The initial symptom is pain in the area of the bite, similar to a pinprick or even little felt at all.
  • Within about 15 minutes, a dull pain spreads to the muscle of the chest, abdomen, back and/or across the body.
  • Other symptoms can include:
    • pain for up to about 12 hours or several days.
    • severe cramping or rigidity of the abdominal muscles
    • anxiety, difficulty breathing, headache, high blood pressure, increased salivation or sweating, light sensitivity, muscle weakness, numbness, nausea or vomiting
    • in extreme cases, particularly just before death in children, seizures can occur. Death is rare, but the young and the old and the extremely ill are most susceptible.
  • Severe symptoms generally begin to improve within three days, but mild symptoms may continue for weeks or months.
  • If bitten, seek emergency medical attention immediately. OSHA also advises the placement of ice on the bite area for 10 minutes on then 10 minutes off, repeating the process.

How to Control Black Widow Spiders

In addition to general spider control methods, in areas where black widow spiders are prevalent, control should target this spider's webs because it spends the majority of its time in its web. Inspection for the spider will be most effective if conducted at night when the black widow is active.

References and Resources