How to tell if a spider is not a brown recluse

I’ve been meaning to make some posts with information on how to identify common spiders for a while, and I will start working on these soon. In the meantime, this post will address one of the most common spider identification questions in North America (north of Mexico): is it a brown recluse?*

brown_recluse2-XL_AlexWild

A female brown recluse, Loxosceles reclusa. Photo: Alex Wild, used with permission.

The brown recluse spider (Loxosceles reclusa) is arguably the most feared and most misunderstood spider species in North America. So, here we will find out how to tell if a spider is not a brown recluse. But before we do, it’s important to note that even if you do find a brown recluse, it’s not that big a deal.

Arachnologist Rick Vetter is an expert on the brown recluse spider who has done a ton of research on where they are (and aren’t) and how dangerous they really are (hint: not as dangerous as you think), as well as spending a lot of time dispelling myths and misconceptions held by both the public and the medical community. His website is full of excellent resources, and is the source of most of the information here. I encourage you to peruse his website and the articles linked in this post yourself, but I will highlight a few of the more compelling reasons that the brown recluse hysteria is unwarranted.

recluse_infestation_Abstract

Exhibit A: brown recluse bites are rare even where the spiders are abundant.

A family lived in a house full of brown recluses (more than 2000 of them!) for half a year and not a single bite occurred. Even in places where brown recluses are common, bites are very rare. Of those rare bites the vast majority of bites can be effectively treated with RICE (rest, ice, compression, and elevation) without any dire consequences. The small percentage of bites that are very serious are the ones that get all the attention in both the medical literature and the media, which has led to the misconception that recluse bites are always severe, require hospitalization, result in extensive scarring, and so on. Furthermore, misdiagnoses of all manner of other (more serious) conditions as brown recluse bites are rampant throughout North America (even in areas where the spiders do not occur), adding fuel to the already raging fire.

Now that all that’s out of the way, here is a series of questions to determine if a spider is NOT a brown recluse**. (Some of these may seem silly, but many of the spiders below that are not brown recluses are regularly misidentified as brown recluses by non-experts. Many people aren’t aware just how many different kinds of spiders there are, and for some, seeing brown, any marking vaguely reminiscent of a violin, and 8 legs is enough to conclude that a creature as a brown recluse.)

For those who want to skip the fine print, if the answer to question 1a or 1b is “yes”, it’s probably not a brown recluse. If the answer to any one of the remaining questions is “yes”, it’s definitely not a brown recluse. 

1a. Are you in Canada (or Alaska)?

brown_recluse_map_Canada_no_text

The range of the brown recluse spider does not extend into Canada. If you are in Canada, you are extremely unlikely to encounter a brown recluse spider. (Also see notes under 1b.)

1b. Are you in a state outside of the range of the brown recluse?

recluse_map_no_text

Here is a map of the known ranges of all of the species in the genus Loxosceles in North America. If you are anywhere outside the red-outlined region, you are very unlikely to encounter a brown recluse.

Brown recluses are occasionally found outside this range – sometimes they hitch a ride with people moving around the country (in boxes that have been stored in basements, for example). But even in these cases they will typically remain in the building into which they are introduced because they are very poor dispersers. Just because one or a few brown recluse spiders have been found in a new area does not mean that their range has expanded or that they are abundant there. (Note: A brown recluse spider bite diagnosis in an area outside their range does NOT mean that brown recluse spiders have been found there. Many doctors erroneously diagnose spider bites in the absence of any evidence, namely a spider that has been identified as the culprit.)

2. Is it on a web out in the open?

Slide1

Some brown web-building spiders that are not brown recluses. Clockwise from top left:       common garden spider (Araneus diadematus) on orb-web, dome-web spider male (Neriene radiata) false widow spider (Steatoda grossa) on cobweb giant house spider (Eratigena atrica) on funnel-shaped sheet web. Photos: Sean McCann.

If you find a brown spider on a web out in the open, it is not a brown recluse. Unlike the various brown web-building spiders shown above, each with their different types of web, brown recluse spiders do not use silk for prey capture. They do build small irregular silk retreats in which they hide during the day. These retreats are made low to the ground and out of sight in cracks and crevices or under objects like rocks.

Update (8/06/2015): I should mention that house spiders in the family Agelenidae are probably the most likely spiders to be mistaken for brown recluses in Canada. While females will usually be found on their webs, males are often found out and about when searching for females. They all look pretty similar to the one pictured below, but see this post for more information house spiders and hobo spiders.

Eratigena atrica

Female giant house spider (Eratigena atrica – formerly Tegenaria duellica). These spiders are often mistaken for recluses, but note the pattern on the abdomen. Photo: Sean McCann.

3. Does it have stripy or spiky legs, or more than one colour on its abdomen?

Stripy_legs

Stripy legs + patterned abdomen = not a brown recluse. Photo: Sean McCann.

If you find a spider that has stripes or large spines on its legs, it is not a brown recluse. If it has a patterned abdomen, it is not a brown recluse.

More_stripy_legs

Stripy legs with large spines + patterned abdomen = not a brown recluse. Photo: Sean McCann.

Brown recluses have plain brown abdomens and plain brown legs with fine hair but no large spines.

4. Does it have extremely long and skinny legs?

Pholcus_phalangiodes

Cellar spider, Pholcus phalangiodes (family Pholcidae). The dark spot on the cephalothorax looks a bit like a violin,  but do not be fooled. This is not a brown recluse. Photo: Sean McCann

If it has extremely long skinny legs like the spider in the image above, it is a cellar spider (or daddy-longlegs), not a brown recluse. Despite looking very dissimilar to brown recluses, these spiders are often mistaken for brown recluses because of the “violin” mark on the back. Having a violin-shaped marking is not, by itself, a good way to determine if a spider is a brown recluse.

4. Is it really big? 

Brown recluses are not huge spiders. If its body length (not including legs) is more than 0.5 inches or about 1.25 cm, it’s definitely not a brown recluse.

5. Does it have 8 eyes? 

This is the dead giveaway, provided you are close enough to the spider to count its eyes. If it has 8 eyes (like most spiders), it is not a brown recluse. Below are some 8-eyed spiders that are sometimes mistaken for brown recluses.

Fishing spider

Fishing spider (family Pisauridae) actually a close relative of fishing spiders in the family Trechaleidae, with 8 eyes. Also see: stripy, spiky legs. Photo: Sean McCann.

 

Wolf_face_IMG_9988

A wolf spider (family Lycosidae). Wolf spiders have 8 eyes and spines on the legs. Photo: Sean McCann.

Sac_spider_IMG_9934

A sac spider (family Clubionidae) A ground spider (family Gnaphosidae, genus Drassodes). It looks a bit like a brown recluse, but again, has 8 eyes, some larger spines on the legs, and a dark stripe on the abdomen. Photo: Sean McCann.

 

Huntsman_aquarium

Huntsman spider (family Sparassidae). These spiders are fairly frequently mistaken for brown recluses. Note the 8 eyes in 2 rows, and spines and darker dots on the legs and abdomen. Photo: Sean McCann.

Update (12/06/2015): Another 8-eyed spider that can easily be mistaken for a brown recluse (and is common in the southern states) is the male southern house spider. It has a similar violin-like marking on the back, but several other features that distinguish it from brown recluses. The 8 eyes are all tightly clumped together, it has conspicuous spines on the legs, and its pedipalps (the two small leg-like appendages at the very front end of the spider) are extremely long and stick straight out in front of its face (compare to a male brown recluse spider here).

Southern_house_spider_Sam_Heck

Male southern house spider (Kukulcania hibernalis). Photo: Sam Heck, licensed under CC BY-NC 2.0.

Some other spiders that are not brown recluses, like the woodlouse hunter Dysdera crocata, also only have only 6 eyes, but they are arranged differently (not to mention D. crocata is red or pinkish or orangish in colour, not brown).

Dysdera crocata on white

Female woodlouse hunter, Dysdera crocata. Her 6 eyes are all in a tight bunch in the centre of the cephalothorax, and her massive fangs are much larger than those of a brown recluse. Also, these spiders are not brown. Photo: Sean McCann.

Brown recluses only have 6 eyes, arranged in 3 pairs.

brown_recluse1-XL_AlexWild

This is a brown recluse. It has only six eyes. Also note the fine hairs on the legs, but no spines, and the plain brown abdomen. Photo: Alex Wild, used with permission.

If you answered no to all those questions (or all but questions 1a and 1b and you’re really lucky!) AND the spider looks just like the one in the image above, then you’ve found a brown recluse. If not, then it’s another kind of spider that is totally harmless. (The only other medically significant spiders in North America are black widows). Either way, please remain calm. Spiders are not out to get you, and will leave you alone if you leave them alone. Here are some tips for avoiding brown recluse bites if you do live within their range. Still not sure about any of this? Please feel free to tweet at me (I’m @Cataranea on twitter) or comment here if you have any questions and I’ll be happy to try to answer them.

 

*I’ve also started answering this question on twitter with the hashtag #notabrownrecluse. This campaign, with the goal of educating people about the brown recluse spider, is a blatant ripoff of inspired by wildlife biologist David Steen (he’s @AlongsideWild on twitter), who tweets snake identifications using the hashtags #NotACottonmouth and #NotACopperhead. For more about his awesome twitter outreach, check out this excellent article: ‘This snake scientist is the best biologist on twitter‘.

**This guide is based on the following resources:

Vetter, Rick. (1999). Identifying and Misidentifying the Brown Recluse Spider. Dermatology Online Journal, 5(2). link

Vetter, Rick. (2009). How to Identify and Misidentify a Brown Recluse Spider. Web Resource. link

46 thoughts on “How to tell if a spider is not a brown recluse

  1. Always so interesting reading your posts, the more spidery the better. I’ll look forward to more of them.

  2. There’s another brown spider that is dangerous and becoming quite common in the Florida area.

    The Brown Widow. It has the same hourglass as a black widow on the bottom of their abdomen. If you get a close look they’re brown with darker brown or green markings on their abdomen.They have long legs with darker areas on the joints. They’re actually kind if beautiful markings. They make a messy looking web in a corner somewhere.

    They’re not aggressive that I’ve noticed. But I wouldn’t want to get bitten so I stay back.

    I found two in my garage on either side of the door. I found one under my daughters bike set. Another in a drain pipe, on a fire hydrant, in the eves of a covered patio, and on the back of a patio chair.

    I live in St. Augustine, Fl.

    • Thanks for commenting! Yes, when I said “black widows” are the only other medically significant spiders in North America I should have said “widow spiders” to include the invasive brown widow (there are also red widows in Florida!). They are indeed beautiful spiders, and not at all aggressive, just like their relatives the black widows. If you don’t bug them, they will definitely not cause you any problems! They are shy and very hesitant to bite. Do be careful reaching into dark corners or woodpiles or inside/under anything that’s been left outdoors in case they have built a retreat there, though. Accidentally grabbing them, stepping on them or crushing them (if they are hiding in a boot or work glove for example) *is* a good way to potentially get bitten.

      • Can you help me determine if the spider I saw in my car this morning is a recluse? I have a picture. I am in Jacksonville, FL, just a few miles North of St. Augustine.

  3. thank you! I have been trying to explain that the odds of finding a Brown Recluse in North Carolina are extremely slim. Still I hear doctors tell patients bite are likely from a recluse all the time!

    • You’re welcome! I hope this post proves useful! Doctors also (mis)diagnose brown recluse bites in Canada all the time as well, making people think they are here, which they are not!

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  5. When a misdiagnosis occurs, what is being misdiagnosed?
    Especially if widow spiders are the only other medically significant spider.
    So what is biting people to give them a reaction that they need to have treated?

    And thank you for breaking down the identification process so neatly.

    • Great question. There are many things that are misdiagnosed as spider bites. It could be a bad reaction to a bite from another arthropod (ones that are far more likely to bite than spiders, because they actually feed on blood, which spiders do not) such as a tick, flea, or mite. In many cases, necrotic lesions are diagnosed as brown recluse bites even when there is no reason to think that a bite ever happened – it could be a tiny scratch that got infected, for example. Here is a list from Rick Vetter of some of the many things that have been misdiagnosed as brown recluse bites: http://spiders.ucr.edu/necrotic.html (scroll down to the table at the bottom of the page). It is important to note that some of these – Lyme disease for example – can become very serious if not treated correctly. If a person has Lyme and is treated for a recluse bite (treatment is RICE), they will not get appropriate care (Lyme can be effectively treated with antibiotics, but gets much worse if these are not administered right away) and the outcome will be far worse. This is why misdiagnosis of spider bites is so harmful. Another post on the topic here: http://spiderbytes.org/2014/09/25/the-truth-about-spider-bites-aggressive-spiders-and-the-threat-to-public-health/

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  8. Hello,
    I am so glad I stumbled upon your blog as I was hoping to tell myself I did not see a brown recluse. I have night terrors and it’s always the same where I get attacked by spiders. So needless to say I’m not a big fan of being too close. Any how I live in southern Indiana and I was in our laundry room I moved some closed and what looked like to me a brown recluse and it moved really fast and I saw a tiny bug running from it. It moved fast and seemed defensive not sure if that’s a characteristic of them or not? I live by a lot of farm land also. So my biggest fear is that I have a two year old and I’m afraid what if he sees one and attempts to grab it or get close to it? Are they generally the type to stay inside the home or lay eggs around? Sorry I know these may seem silly I just have no idea.
    Thanks,
    Mercedes

    • Hi Mercedes, thanks for commenting! Your questions are not silly at all. You could very well have brown recluse spiders where you are in Indiana. To find out for sure, you could put sticky traps out along your baseboards and then if you capture one it would be easier to identify. It’s really hard to say just from the behaviour you described what kind of spider it might be. Recluses like to live in dark spaces and hide out in cracks and crevices or behind things – they generally aren’t found out in the open, so I doubt there is much risk of your child seeing one and grabbing it. Also they are very fast and would likely run rather than turn and try to bite if someone was attempting to catch them. That said, Rick Vetter has some good advice here: http://spiders.ucr.edu/avoidbites.html on avoiding bites if you do have recluses in your house. The danger is having lots of cluttered objects or clothes that recluses might be hiding under or inside, and then accidentally grabbing the spider when reaching behind or in those objects, or putting on clothes that the spider is inside. Unless they are being grabbed or crushed, most spiders are very hesitant to bite! I hope this helps, and please don’t hesitate to ask if you have further questions! You can also email me – my contact info is on the about me page.

      • Thanks! I’ll be sharing…I am really getting bothered by how this spider has been maligned. Every brown spider in the U.S is in danger of being squashed…even though they eat flies and everybody knows there is nothing grosser than a maggot!

    • Thanks so much for the tip! You are right, it is Drassodes – we did not correctly ID it until after I made this post. I have now corrected the caption!

        • Oh good catch – I knew that! You’ll see earlier in the post I used Eratigena atrica, but then relapsed for the second caption! Still getting used to those name changes.

  9. Very good information. Thank you. I live in Missouri so 1b was yes and I live in the country. I learned most here are orb or the many looks of wolf spiders. Although after being bitten by ‘some kind of spider’ to just be more careful. I rarely rake leaves in fall anymore. I didn’t see what bit me but sure felt it afterwards. Belly bite left a scar about nickel size. Swelled and became pussy within the hour. Used Epsom salt compresses and antibiotics and eventually went away. I’m saving this to post to friends.

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  11. Im pretty sure I just ran across a brown recluse 30 minutes ago when I began stepping into the pool to clean it (above ground pool). So I researched photos and sure enough almost exact to several pictures shown of brown recluse spider. I had my son come with me to take a photo and he first said “mom stop freaking out its just a wolf spider!” He left me outside alone in pool, trying to get it out so I could clean it, then a few minutes later he was right beside the latter checking on me. Saying he looked it up and realized it was NOT a wolf spider. Now I am too scared to get in to clean it, unsure how many more might be lurking around. Any advice… yoUnger sons party is this Saturday and was hoping to have pool clean and atleast 1-2 ft of water to splash around. Thanks for all your info above, and any other you may have as well. Very helpful. Sabrina

    • Hi Sabrina,

      Recluse spiders are unlikely to bite unless they are trapped against your body, so I would recommend cleaning areas where you think they might be wearing long sleeves and pants and gardening gloves. Rick Vetter has some information here on how to avoid bites: http://spiders.ucr.edu/avoidbites.html. Hope this is helpful – please feel free to email me if you have further questions!

    • They generally try to stay hidden (they are not called “recluse” spiders for nothing!) but sometimes you may see them wandering.

  12. I am at my grandmother’s house letting kids stay cool in this summer heat (grandmother has been in nursing home for several months house has been empty) I was going through a closet in the dining room and bumped into some table cloths hanging on closet door when I seen a spider shoot up the side of cloth. I caught it in a jar and have googled it and am almost 100% it is a Brown recluse now just second guessing if here in the a/c is safer then home in a 90° house??? Help please is there anything I can do to help make sure there are no more???

    • Hi Sarah, if there are brown recluse spiders in the house here is some good information on how to avoid bites: http://spiders.ucr.edu/recluseid.html
      Putting out sticky traps is one way to see if there are more around. If you have more questions, please feel free to email me at catherine.scott [at] mail.utoronto.ca

  13. When I was younger I had gotten bitten by something (southern Kansas). On day 2 the bite was a bullseye of red, purple, black and white. I was taken to the ER where they gave me a shot. They had said it was just a brown spider but not a brown recluse bite. Is that even possible?! Also, I think I might have seen one on my bed last night. Although, I squished it in my panic and squished it a little too hard to where it now doesnt have an abdomen. But there is a fiddle-like shape on its back and its legs are all one color. With legs stretched out it was about the size of a quarter. It ran from me instead of to me (hallelujah) but still scared the crud out of me! I usually don’t mind spiders and just leave them be, but if they are within 1 foot of me or on me they are getting crushed! Because I’m a pansy!

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  15. I found a spider that looks just like a brown recluse this morning in my kitchen. I have a ton of spiders almost a infestation but was never scared till today.I’m 99.9% sure it’s a recluse but I live in Maryland so what do you think? Also could there be more? I have a picture but it’s from a distances lol.

  16. Very nice article. I really enjoyed reading it. I live in west Texas. I have found about 6 brown recuses in the past 2 weeks. I will admit I killed one. Just because I was putting my leg though a pair of shorts and saw it out of the corner of my eye and flipped. But the others have been released outside. The arachnids we have are amazing. I love the sun spiders just amazing creatures, but my wife just absolutely hates them.

  17. Southern house spider. Im not gonna get much love from an arachnophilanthropist such as yourself, but anything that looks that much like a brown recluse isnt going to live long. It wasnt until I saw ths blog that I know the species existed. I smashed one weeks ago thinking I had finally seen a brown recluse. I have huntsmen spiderscrawl under my door and unless its a female either carrying or covered I leave them to the mercy of the gauntlet of cobweb spiders I have inhabiting the underside of my cabinets. Sometimes I even toss them back out. But the risk, however small, of drastic permanent damage to any part of my body is not worth sparing a potential danger I can see plainly.

    Thankyou for finally putting to rest the trouble of finding a good source for what IS a brown recluse. You’d be amazed how hard it can be just to get a good picture of something so widely known in this day and age of cameras everywhere.

  18. Excellent information to have! I live in SC, and people are always thinking they have seen a brown recluse. I have now shared this to my fb page. Thanks!

  19. I live in MS and we recently rented a very nice house but no one had lived there for several months. I was cleaning one day and found what I am almost sure was a brown recluse so I put out glue traps to see what else was crawling around. Within 4 days I had at least 15 of the same spider stuck on the traps. All sizes and a couple even looked to be pregnant. I contacted the landlord and she says they are not brown recluse. I have pictures. Could you please help me identify them?

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