I’d intended today to post on my Arizona-​​themed Magic deck (men­tioned here), but some­thing hap­pened last night that changed my mind.

Wednesday we hosted a pre­sen­ta­tion on ven­omous crea­tures of north­west­ern Arizona — the talk was about the A-​​listers with poi­son, such as Western dia­mond­back and Mohave rat­tlesnakes, Gila mon­sters* and scorpions.

That night (last night), while I was watch­ing MythBusters (a rerun but I hadn’t seen it the first time around), I noticed motion in my periph­eral vision.

There was a spi­der crawl­ing slowly up the wall.

Not at all unusual, actu­ally. My apart­ment is hardly sealed from the ele­ments — the screens are a lit­tle loose, and I reg­u­larly keep the door open to let some breeze in at night — so I occa­sion­ally get vis­i­tors. Whenever pos­si­ble I like to trap my lit­tle guests and put them back out­side, where they are quite wel­come to dine on roaches, crick­ets and so on.

I upended the candy dish — actu­ally the con­tainer that a Specialized cyclo­com­puter was sold in — and trapped the spi­der under it, tipped it into the can­is­ter and lid­ded it. Looking the spi­der over, though, I real­ized it wasn’t what I was expect­ing to see, a small wolf spi­der. It was def­i­nitely a wan­der­ing style of spi­der … but the cephalotho­rax and abdomen seemed too small in rela­tion to the legs.

Photos after the flip, as well as the rest of the story.

Just to give you a sense of the size of this thing, here it is inside the dish I trapped it in, with a pen nearby for scale.

Spider with pen nearby

As you can see, it’s really small. You might sur­mise too that it’s a good climber — after all, it made it to about chest height on my apartment’s wall before I spot­ted it. It’s perch­ing here on a plas­tic notch inside the con­tainer, I think because it’s the only thing the spi­der can really grab onto.

The spi­der did not go to my office in its uncov­ered state — I lid­ded it and kept it lid­ded when I caught it the night before, par­tic­u­larly after my sus­pi­cion grew to some­thing approx­i­mat­ing certainty.

While many web­less spi­ders have a sim­i­lar body plan, I’m famil­iar with the wolf and hunts­man vari­ety (and I’ve kept taran­tu­las), so I knew I wasn’t look­ing at any rep­re­sen­ta­tive of those types. I got my cheesy mag­ni­fier out and looked closely at the spi­der and saw some­thing like what you see in the fol­low­ing pho­to­graph. (BTW, all the images here were taken with the Nikon D50 I use at work.)

I’m not sure, but given the struc­ture of the vio­lin shape on the cephalotho­rax, as well as the faint lines radi­at­ing out to the legs, I think the dark­en­ing we see here might rep­re­sent nerve clus­ters or bun­dles that cen­tral­ize near the eyes and che­licerae. If I recall cor­rectly spi­ders’ blood is gen­er­ally trans­par­ent, so I don’t think this is a mass that rep­re­sents blood ves­sels or a heart loca­tion. In fact I seem to recall that spi­ders have their hearts in their abdomens.

Cephalothorax close-up

With the con­trast enhanced slightly, it’s pretty obvi­ous what I have here. I did some pok­ing around online last night and came away with two things:

  1. About 95% cer­tainty; and
  2. A pretty sub­stan­tial case of either the hee­bies or the jeebies.**

Today I con­firmed it. This is an Arizona brown spi­der — what in other parts of the US is called a brown recluse. It’s pos­sessed of necro­tiz­ing venom capa­ble of doing sub­stan­tial tis­sue dam­age; in some cases ampu­ta­tions are required. Deaths have been reported as well. It shares, with the widow/​black widow spi­der, the dis­tinc­tion of being the most poi­so­nous arach­nid in the United States.

I brought it to work today to con­sult our local expert; he con­curs with my iden­ti­fi­ca­tion. In addi­tion to the vio­lin shape on the cephalotho­rax, dis­tin­guish­ing char­ac­ter­is­tics are long legs, promi­nent pedi­palpi, tan col­oration and three pairs of eyes arranged sym­met­ri­cally around the forepart of the cephalotho­rax. (Most spi­ders have eight eyes, often along a cen­ter­line on the cephalotho­rax. The browns and recluses have only six, set in a semi­cir­cle. It was the eye count and arrange­ment that was the clincher for me, since the Arizona browns’ vio­lin shape is quite indis­tinct under most light­ing conditions.)

Brown spider traits

Brown Spider traits (PDF, 145 KB)

In addi­tion to the iden­ti­fy­ing traits for this spi­der, you might take note that this spec­i­men is miss­ing two legs, one from either side of its body. This leads me to think it was, until fairly recently, an outdoor-​​dweller. While I can’t say for cer­tain that I’ve tracked every instance of wildlife in my home, I’m fairly sure that there’s noth­ing inside which could take the legs off a brown spider.

Although I’m not par­tic­u­larly delighted to have dis­cov­ered this type of spi­der in my home, I’m not going to kill it. At the moment it’s extremely well con­trolled; it’s in a plas­tic con­tainer with a secure lid that’s been taped in place, so it poses no threat to me or any­one else. This evening I’ll take it out into the desert, a decent dis­tance from people’s homes, and let it go.

I just thought it was a pretty strik­ing con­ver­gence — first my post on our wildlife, then the sem­i­nar on ven­omous local ani­mals; now this.

One other thing. The car­pet in my apart­ment is a sculp­tured hi-​​lo shag of a mot­tled sand-​​and-​​tan shade that would pro­vide almost per­fect cam­ou­flage for this spi­der — and its friends the scor­pion and the solifuge. It might be time to con­sider ask­ing the land­lord for it to be swapped out in favor of a less-​​concealing color and pattern.


* These lizards are dan­ger­ous to humans if you pick them up, spend about five min­utes piss­ing them off and then stick your fin­ger in their mouths and ask, politely, to be bit­ten please. They’re slow, slug­gish and not even remotely aggressive.

Anyone who has been bit­ten by a Gila mon­ster prob­a­bly deserves to die, just for being such a use­less idiot to have suc­cess­fully man­aged to goad the lizard to bite him in the first place. A safe assump­tion is that if some­one has been bit­ten by a Gila mon­ster, sobri­ety was not a fac­tor in the event.

Unfortunately, their bites are pretty much never lethal. Hence the Survival of the Dimwittest, and Bush’s 28% approval rating.

** Or, pos­si­bly, both. I’m not afraid of spi­ders, par­tic­u­larly, but browns and wid­ows do dis­turb me some­what. One of the very few times I ever saw the late Steve Irwin get vis­i­bly ner­vous han­dling an ani­mal was when he was show­ing a widow spi­der. Bites from these crea­tures can be extremely serious.


UPDATE: The release was suc­cess­ful. I took it into a remote area and let it go near a decent patch of low brush. It van­ished against the ground cover almost instantly.

Most peo­ple I spoke to Wednesday believed I should have killed it, but I didn’t see a rea­son and still don’t. From the moment I’d trapped it in the secure can­is­ter its poten­tial for dan­ger to me or any­one else was entirely neutralized.

I learned some­thing, too. Brown recluse spi­ders are del­i­cate, appar­ently quite frag­ile, sur­pris­ingly mild-​​mannered — this spi­der was not even remotely aggres­sive — and they’re so small as to be translu­cent. I sup­pose that’s why they hide most of the time; they have about the same pos­si­bil­ity of con­sti­tu­tion and strength as a daddy-​​longlegs (which, by the way, does not have the most potent venom in the world, despite rumors to the con­trary; its venom is barely toxic at all). I sup­pose the potent venom is mostly to make up for their rel­a­tively weak bod­ies in their nat­ural envi­ron­ment as predators.

I’m much more creeped out by (ven­om­less) solifuges, in fact, than I am by brown recluses. That’s not to say I want brown spi­ders around or that I don’t have respect for them; but I’m not spooked by the thought of them any more. That twenty-​​four hours I spent with one in rea­son­ably close inter­ac­tion turned out to be quite instruc­tive, and I’m glad I had the oppor­tu­nity to see one alive and set it free — at a good dis­tance, of course, from anyone’s home.

That said, I should note that brown/​recluse spi­der bites are extremely seri­ous. If you think you’ve been bit­ten by a brown — or a widow — you must get med­ical help imme­di­ately. There’s no rea­son to panic, since early treat­ment will stop the worst effects, but the very last thing you want to do is “watch it for a few days and see what happens”.

The necrotic effects of a brown’s tox­ins are suf­fi­cient to kill off a lump of flesh inside your body roughly the size of a ten­nis ball if the bite goes untreated. Even with a delay of just a day or two, you could extend your recov­ery time to months or years rather than just days or weeks.

Bite reac­tions start with a white blis­ter that expands in an angry, red sen­si­tive ring that looks like a bull’s eye, and tend to hap­pen in thin­ner skin areas like the web­bing between fin­gers, or where the spi­der has been con­stricted against your skin by cloth­ing or per­haps in bed.

Other symp­toms include feel­ings of hav­ing the flu, stom­ach cramps and vom­it­ing. If you’ve been bit­ten and you have any of these symp­toms, get to a doc­tor right away. Don’t make an appoint­ment for next week. It’ll be too late and, depend­ing on where you were bit­ten, you could be in rehab while you regrow a sub­stan­tial amount of mus­cle — or you could lose a limb.

Ask my grand­mother some­time, or my boss, both of which women were very lucky to have sur­vived bites with no last­ing dele­te­ri­ous effects on their well-​​being. Or ask my dad’s tough-​​as-​​nails fire­fighter friend who lost a leg when he was bit­ten behind the knee … and ignored it.

Brown spi­ders all.


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