Venomous Spider Types
Most Spiders Are Poisonous
According to the Children’s Hospital of Pittsburgh, the majority of the 20,000 spiders found in the U.S. are poisonous. Humans are safe from most of them, however, because our skin protects us. This is because most spiders’ fangs are too small or weak to break through it. Those that do manage to bite us don’t usually cause serious problems. We may scratch an itchy, red wound, but it heals within a week or so.
A small handful of spiders, however, can cause serious problems. Here’s a closer look at a few of them.
Called the “violin” spider because of the dark marking on its back, the brown recluse is found in states like Missouri, Kansas, Arkansas, Louisiana, Oklahoma, and eastern Texas. About an inch long and usually non-aggressive, it bites only if caught off guard. It typically hides in dark, secluded spaces.
The initial bite may be painless, but gradually will itch, hurt, and turn red. Within eight hours, red rings form around a white center. Called a “bull’s eye” or “target lesion,” this bite can blister and grow progressively worse without treatment. At its most severe, it may kill surrounding tissue and cause fever, chills, and headache. There is no antidote for a brown recluse bite, but treatment can encourage faster healing.
The black widow spider is shiny and black with a distinct, reddish hourglass-shaped mark on its belly. Found mostly in the warm southern and western states, the black widow likes hidden spaces. It will often lurk under fallen leaves, in woodpiles, and under boxes in the attic. If you run into one of their webs, you could suffer a bite.
If you suspect a black widow bite, look for two puncture marks on the skin that cause pain and burning. Other symptoms include cramping stomach pain, headache, weakness, muscle rigidity, sweating, and more. Prompt treatment is best, especially for children.
If you live in the Pacific Northwest, you likely already know about this large brown spider. Like monster trucks, they sit up high on long legs and run fast. They’re aggressive, and may attack if provoked. Watch out if you’re cleaning window wells or sweeping out the garage. They also lurk behind furniture, under baseboards, and in closets.
A hobo spider bite takes a while to get your attention, but it will eventually cause pain. Other symptoms may include a red/purple blister, rash, muscle pain, difficulty breathing, headache, fever, high blood pressure, nausea and vomiting. Like a brown recluse’s bite, it can leave a blister that ulcerates, and is slow to heal.
Common all over the country, wolf spiders measure three to four inches long. They like to stalk their prey, which is how they got their name. Similar to tarantulas in appearance, they hunt on the ground. You’ll find them in sand and gravel, around the bases of doors and windows, or in house plants. Look for two large eyes in the middle of their faces. The other six eyes are smaller.
A wolf spider’s bite may tear the skin, and will cause pain, redness, and swelling. You may also experience swollen lymph glands as a result of the bite. Healing can take up to 10 days. The most severe type may cause tissue damage, but this is rare.
Southwest states with desert climates host tarantulas, but they may also be found as far east as the Mississippi River. Look for them under logs or stones, under tree trunks, and in tunnels or burrows. You can usually identify them by their size (from 3 to 5 inches long), texture (hairy), and by the visible fangs that hang down.
Tarantulas are not aggressive. If they bite, it will feel like a bee sting, and will become warm and red. The pain can be significant. Other potential symptoms include a rash, swelling, itching, rapid heart rate, eyelid puffiness, trouble breathing, and low blood pressure.
Found in desert climates (Utah, New Mexico, and Texas), the sand-colored camel spider is easily identified by the powerful pincer on its head. Although it resides in the desert, it doesn’t like the sun. A camel spider will always seek the coolest place around, which just may be your shadow. A fast runner (up to 10 mph), it may be only 2 to 3 inches long, but in some locations, it grows up to 6 to 8 inches in length.
Because of its large jaws, a camel spider can leave a significant wound in human skin. These spiders don’t produce venom, however, so you won’t experience poisonous symptoms. Instead, the main concern is infection, which can be prevented with proper treatment.
Brazilian Wandering Spider
Native to Central and South America, it’s nicknamed the “banana spider” because it may hide in bunches of bananas sent to the U.S. Be wary when opening boxes and packages sent from other countries. Growing up to 5 inches long, this spider moves quickly and aggressively, and is typically a yellow-brown color with black stripes and red hairs on its fangs.
Considered one of the most poisonous spiders in the world, the Brazilian wandering spider can cause severe symptoms and even death. The bite is extremely painful, and can quickly result in heavy sweating and drooling. Seek emergency treatment immediately. An antivenom is available for this spider’s bite.
One of the most common household spiders, the jumping spider exists throughout the United States. Usually only a half-inch long, it has a stout, hairy body. The most common type is black with white spots on top. It’s best identified by its erratic jumping/walking gait. You’re likely to find it outside in gardens and near other vegetation. Indoors, it’s usually near windows, as it likes to look out.
The bite is venomous, but usually no worse than a wasp bite. Symptoms include pain, itching, and redness, and there may be significant swelling. They will attack if threatened, so use gloves when gardening.
Identifying Spider Bites
Identifying a spider bite is easier if you saw what bit you, but sometimes you may not notice the wound until hours later. Look for things like swelling, a “red welt,” and skin damage, as well as any troubling symptoms that accompany the bite.
Spider bites often take longer to heal than other insect bites, and may affect skin tissues. It is important to keep the bite clean to reduce the risk of infection.
If you experience other symptoms—such as fever, chills, stomach upset, rash, headaches, swelling, anxiety, or swollen lymph glands—speak with your doctor right away.
- Brown recluse spider. (2009, October 5). National Institutes of Health. Retrieved September 4, 2013, from http://www.nlm.nih.gov/medlineplus/ency/article/002859.htm
- Diaz, J.H. & Leblanc, K.E. (2007, March 15). Common Spider Bites. American Family Physician, 75(6), 869-873. Retrieved September 4, 2013, from http://www.aafp.org/afp/2007/0315/p869.html
- Drees, B.M., & Jackman, J. (1999). Tarantula. Texas A&M AgriLife Extension. Retrieved September 4, 2013, from https://insects.tamu.edu/fieldguide/cimg366.html
- Roe, Alan H. "http://extension.usu.edu/files/factsheets/hobospid.pdf." extension.usu.edu. Utah State University Extension, 25 June 2003. Retrieved September 4, 2013, from http://extension.usu.edu/files/factsheets/hobospid.pdf
- Spider Bites. (n.d.). Children's Hospital of Pittsburgh of UPMC. Retrieved September 4, 2013, from http://www.chp.edu/CHP/P02850
- Tarantula spider bite. (2011, December 15). National Institutes of Health. Retrieved September 4, 2013, from http://www.nlm.nih.gov/medlineplus/ency/article/002855.htm
- Top 20 Arachnids. (n.d.). Utah Plant Pest Diagnostic Lab, Utah State University Cooperative Extension. Retrieved September 4, 2013, from https://utahpests.usu.edu/uppdl/htm/top-20-arachnids
- Venomous Spiders - NIOSH Workplace Safety and Health Topic. (2013, July 11). Centers for Disease Control and Prevention. Retrieved September 4, 2013, from http://www.cdc.gov/niosh/topics/spiders/