The brown recluse, loxosceles reclusa, is one of the more dangerous spiders indigenous in the United States. While usually not life-threatening, a brown recluse bite might lead to severe skin damage. This page gives an overview of how to identify a brown recluse and in which states in the US it appears.
Brown Recluse Description
The brown recluse spider is usually a brown to tan color, but can sometimes have more of a gray shade to it.
The Abdomen is oblong and a little larger than the cephalothorax, while the legs are approximately twice the length of the body. However, they can vary from medium to very long and lanky looking.
How to identify a brown recluse spider?
The Brown Recluse does NOT have spiny hairs on the legs, spots or stripes on the legs or abdomen, any bright colors, or short fat legs. If you see a spider with any of these, it is not the Brown Recluse. Wolf spiders or woodlouse spiders are often confused with the brown recluse, even though there are several differences between the species. Some good rules to follow in identifying the recluse spider are:
- Eyes are in three very distinctive and separate pairs for a total of 6 eyes. Two in the middle and two on each side, Each pair is tightly knit and there is a very distinctive distance between the pairs.
- On the back of the Cephalothorax (not the Abdomen), there is a darker pattern in the shape of a violin. Hence the reason for the nickname “the fiddle back spider”.
- Is there any other patterns or markings on the spider? If there are any markings on either part of the body or legs, other than the violin, it is not a recluse.
The Brown Recluse has six eyes, which are grouped into three pairs. All six eyes are about the same size. Two right next to each other in the middle, an easily discernible space to each side and another pair that is very close to each other to each side.
The body will reach up to about 3/4 of an inch (19mm) and with the legs included may be around 1 ½ inches (38mm).
Usually, the Brown recluse does not spin much of a web. It is not like many spiders that uses their web to catch prey, instead, it wanders out at night to hunt its prey. When it does spin a web, it is usually to nest and lay eggs. The web is small, sometimes as little as an inch across and looks to be randomly built with no design.
Brown Recluse Bite
The recluse is not prone to biting. It is not an aggressive spider at all. When it does bite, it is almost always due to someone pressing against one and it is forced to bite to defend itself.
In cases where it does bite, the recluse will often administer a dry bite that is virtually harmless. If it does use venom, it is often that the venom will not have much of an effect.
However, there are those bites when the venom does have a serious effect. Its venom is a cytotoxin which will break down the tissue around the bite, causing a wound that looks as if the flesh is rotting. This wound will usually grow to around 3 or 4 inches across.
Even if you might not feel a strong pain immediately, you should definitely visit a doctor if you think you’ve been bitten by a brown recluse spider. Especially if you are in one of the US states where the brown recluse usually lives.
Loxosceles reclusa Distribution in the US
The map below shows the range of the brown recluse spider in the US. The shaded areas of the map are where the spider is considered to be indigenous. The closer to the edge to a shaded area you get, the less likely it is you will find this spider. Outside of the shaded area it is very unlikely you will find one.
The brown recluse spider can be found in the following US states: Alabama, Arkansas, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Mississippi, Missouri, Nebraska, North Carolina, Ohio, Oklahoma, South Carolina, Tennessee and Texas.
The list here does not exclude that a brown recluse spider may also be found in any other US state. These are just the states in which the spider is mostly indigenous.
Facts about the Brown Recluse
A large number of brown recluse bites are false diagnoses
The dangers of the infamous Brown recluse have been so over blown that there are sometimes more reports of recluse bites in states where the spider is not even indigenous than in states where it is common.
The problem is that many doctors will learn about the bite in their training, especially when they train in states where the recluse is common. Then, when they have a practice in a state where the spider is not indigenous, they will often misdiagnose other serious problems as recluse bites.
The brown recluse does not like to wander around
The recluse got its name for a reason. It is a very reclusive spider. A house can become infested with thousands of brown recluses. While the houses next door may never see even one recluse spider. They will build their colony and stick to it.
Where other spiders are known to wander, looking for a mate or good place to nest, the recluse sticks to the location it was born. They will wander at night, but never very far from their nest.
This fact, and the fact that they cannot survive in freezing temperatures is the reason that the range of the Brown recluse does not expand over the years.
Though they are not indigenous to many states, there may be cases where the recluse is identified in those states. I have, for instance, been part of two cases where we identified the brown recluse spider in Michigan. And I know of a few others. These cases do not mean the Brown recluse spider is in Michigan, or any other state this happens.
It is not unheard of for boxes, crates, furniture or whatever to have recluse spiders inside of them to be transferred from a state where they are indigenous to a state where they are not.
Fortunately, these spiders that are transferred will not survive in the new habitat and will not and populate those states. On a very rare occasion, there may be multiple spiders transferred and they might breed.
As long as the building they are in stays warm, they will survive and continue to breed and colonize that building. When found, these colonies are exterminated. This is incredibly rare, though.
Its reputation is worse than the reality
The Brown recluse is one of the most feared spiders in the world. But its reputation is far worse than the truth. It is not as dangerous as most people think. That does usually not matter when it comes to fears. Because the recluse is so feared, it is reportedly biting people in every state of the country. Even in the many states where this spider is not even indigenous.
Indigenous. That is the key word here. Just because a spider is not inhabiting a specific state, does not mean it will never be found in that state. People move around a lot. People send packages all over the USA. All over the world.
Anywhere people travel or send packages, has the possibility of finding a spider that just happened to get shipped along with the item in the packaging.
These sightings do not mean that spider is living in that state. It means a rogue spider was transferred to that state and nothing more. I will use Michigan as my example since I am from this wonderful state and am familiar with its findings. In Michigan this spider has been found and identified probably less than a dozen times now… Ever! In almost every case it was easily tracked to being brought into the state by shipment or people traveling.
You could spend the rest of your life searching for a brown recluse in Michigan and likely you will never find one. It will only be found by someone who somehow had it shipped to their home or business in some manner.
Loxosceles reclusa scientific classification
- Kingdom: Animalia
- Phylum: Arthropoda
- Subphylum: Chelicerata
- Class: Arachnida
- Order: Araneae
- Infraorder: Araneomorphae
- Family: Sicariidae
- Genus: Loxosceles
- Species: Loxosceles reclusa
Brown recluse, fiddleback spider, brown fiddler, violin spider.