How to Identify a Brown Recluse Spider

There are only two deadly poisonous spiders commonly found in North America. One of these spiders, the black widow, has made its way into popular culture with its distinctive look and fantastic name. However, the equally deadly brown recluse is often overlooked. These spiders are not aggressive, but it is best to know how to identify one so they can be avoided.

Behavior

The brown recluse is named as it is because it does not often come out into the open. Brown recluses hunt at night and rarely stray too far from their web. It is very rare to see the spider unless one disturbs them from a quiet, dry place. They often make webs for homes in sheds and garages, but their natural habitat is in rotting trees. Since the spider is happy to avoid humans, most brown recluse bites happen when the spider is hiding and is caught up next to human skin in blankets or clothes. There are very few reported cases of bites each year, because they will not attack until they touch human skin.

Effects

Those who are bitten by a brown recluse may not even notice. The bites are fairly painless and the poison will start to degenerate the flesh immediately, leaving a deep wound that takes a long time to heal. This process is called necrosis. The symptoms that begin to develop within a few hours are known as loxoscelism after the scientific name of the spider. The victim begins to experience fever, nausea, vomiting, rashes, and pain. In very serious cases, the blood begins to clot rapidly inside the body and the red blood vessels stop functioning normally.

Those who are bitten should apply a cold pack to the area and call emergency services. Most fatalities from brown recluse bites are children under 7 or those with disabilities that have weakened immune systems. However, healthy adults also need to seek immediate medical attention if they believe they have been bitten. Treatment will be much more effective if the spider is identified as a brown recluse. Many other common afflictions are misdiagnosed as brown recluse bites. In actuality, the spider bites are not very common.

Native Regions

The brown recluse is a native North American spider. The heaviest concentrations of the spider are in the mid-southern United States. They are spread as far north as Ohio and as far east as Georgia. The concentration once stopped in East Texas and Kansas, but more recently the spiders have been found in the desert terrain of the Southwest. Now, the brown recluse can be found in Southern California.

Physical Characteristics

The brown recluse is a fairly small spider that ranges from one fourth of an inch long up to about an inch. Its legs are slightly longer in proportion to its body, but it should not be confused with other long leg spider varieties.

Obviously, the brown recluse is brown in color. The shade will vary from spider to spider. They have been documented as light tan all the way to chocolate brown. The color is soft and mostly even because of the fine hair that covers their body. The most effective way to identify a brown recluse is by the marking on their cephalothorax or prosoma (the “back” below the eyes). The marking is a dark spot shaped like the top of a violin. The marking looks as if the neck of the violin is pointing down towards the thorax. However, some young or unique spiders do not have as noticeable markings as others, so sometimes the violin mark is hard to see.

Most arachnids have eight eyes, but the brown recluse has six. This may be hard to see if the spider escapes, but a quick check of the eyes on the dead culprit will verify its identity. The eyes are set in pairs on the top and either side of the spider's head. Most eight-eyed spiders have a large cluster of eyes near the front. Other six-eyed spiders look nothing like the brown recluse and feature stripes.

What to do

If you feel that a brown recluse may have bitten you, make every effort to find the spider. Proper identification can help avoid misdiagnosis. If you are not in a region where the brown recluse is found, finding and identifying the spider is doubly important. Wounds that look like spider bites aren't likely to be from a brown recluse, but if you are experiencing the symptoms listed above, call a doctor immediately.

Most bites are not fatal, but a hospital stay will probably be necessary. Always practice caution around poisonous animals and do not provoke them.