In light of how many spider webs I’ve walked into lately, I thought it might be a good time to familiarize myself with poisonous spiders. There are eight fairly common poisonous spiders in the United States. Most spiders bite when threatened — they don’t tend to run around chomping on people otherwise.
Widow spiders are probably the most common kind of poisonous spider in the United States. They are approximately the size of a blueberry, and have the infamous red hourglass shape on their undersides. Body color and hourglass shape vary from one species to another. Widow spider venom is a neurotoxin that can cause severe muscle cramps and paralysis.
- The southern black widow is found in southeastern states, as far west as Texas and Oklahoma, and as far north as New York. This spider tends to live in cool, dark places — like beneath trash piles and wood piles. The hourglass on the southern widow is shaped more like an anvil than a true hourglass.
- The western black widow may be found anywhere in the western United States, in both urban and suburban areas. This spider tends to inhabit abandoned rodent holes. The hourglass on the western widow is usually a true hourglass shape, but may be split into two distinct pieces.
- The northern black widow lives in wooded areas in southeastern Canada, New England, and south into Northern Florida. This spider tends to live in wooded areas, abandoned stumps, and stone walls. The hourglass on the northern widow is split into two long, separate marks.
- The brown widow is found in southern states and can vary in color from brown to grey. The hourglass on the brown widow is a true hourglass shape.
- The red widow is found mostly in central and southern Louisiana and Florida and can vary in color from red to orange. This spider tends to live in sandy, scrubby pine areas. The hourglass is usually one single elongated marking.
Other poisonous spiders include brown spiders and tarantulas. Most brown spiders have fiddle-shaped markings on the midsection (thorax). A brown spider bite usually kills the surrounding tissue and can form an ulcer that lasts for months. The venom may also cause blood disorders that can appear after a few days.
- The brown recluse spiders are the most common brown spider in North America. These spiders like to hide in and under things. Unlike most other spiders (who have eight eyes), brown recluse spiders have six eyes.
- The Missouri brown spider is the second most common brown spider in North America.
- Tarantulas are the largest and hairiest spiders in North America, and are found in the southern and southwestern states. Leg spans can reach four inches or more! Most tarantulas are shy and avoid human and animal contact. The bites are not considered extremely toxic, but an allergic reaction to the bite can be serious.