Black Widow Spider Bite: Is It Poisonous? Find Out Now!

Black widow spiders, belonging to the Latrodectus genus, are notorious for their venomous bites. These spiders have a shiny black body with a distinctive red hourglass-shaped marking on their abdomen, making them easy to identify.

While most spiders produce venom, only a few have the ability to cause harm to humans, and black widow spiders are notably one of them.

A black widow spider bite can be toxic and dangerous, due to the venom it injects. The venom targets the victim’s nervous system, leading to symptoms such as muscle pain, nausea, and even difficulty breathing in severe cases.

However, it’s important to note that adult female black widows are the primary ones with dangerous venom, and they often try to escape rather than bite unless they feel threatened or are defending their eggs.

For those who are bitten, prompt medical attention is crucial. The treatment for black widow spider envenomation often involves the use of antivenin, which can effectively neutralize the spider’s venom.

Black Widow Spider Overview

Appearance and Characteristics

• Shiny black body: Black widow spiders are known for their glossy black appearance.
• Red hourglass shape: They display a distinct, red hourglass shape on their belly area, which is a recognizable feature of black widow spiders.
• Female spiders: Female black widows are larger and more venomous than their male counterparts, making them more dangerous to humans.

Habitat and Distribution

The black widow spider is native to North America and can be found across the United States, including the following species:

• Southern black widow (Latrodectus mactans): This species is more common in the southern regions of the US.
• Northern black widow (Latrodectus variolus): This species, on the other hand, can be found in the northern parts of the country.

Dangerous Spider or Misunderstood Creature?

Although black widow spiders possess venom, they generally pose a low risk to humans. These spiders are not aggressive and usually only bite in self-defense.

Female Spiders and Self-Defense

As mentioned earlier, female black widow spiders are responsible for the majority of bites. When they sense a threat, they may bite to protect themselves. However, the risk of being bitten by a black widow remains low.

Black Widow Spider Bite

How Bites Occur

Black widow spiders, belonging to the Latrodectus genus, are known for their venomous bites. Bites usually happen when these spiders feel threatened or disturbed, especially when guarding their eggs.

Identifying Spider Bites

A black widow spider bite is identifiable by two small pinprick marks caused by the spider’s fangs. It might be surrounded by redness, cause a rash or appear swollen.

Other poisonous spiders exhibit similar bites; however, the black widow has a unique red hourglass-shaped marking on its belly to help with identification.

Signs and Symptoms

A bite from a black widow spider can cause various symptoms, including:

• Pain and itchiness around the bite area
• Muscle tremors
• High blood pressure
• Difficulty breathing

Here’s a comparison table for black widow spider bites and bites from other spiders:

While black widow spider bites are rarely fatal, it’s crucial to seek immediate medical attention if bitten.

Medical Treatment and Home Remedies

When to Seek Medical Help

Seek medical help immediately if bitten by a black widow spider, especially if severe pain, trouble breathing, or other serious symptoms occur.

Bites can be particularly dangerous for young children, older people, and those with pre-existing medical conditions. Symptoms to watch for include:

• Severe pain or swelling
• Difficulty breathing
• Nausea and vomiting
• Sweating and chills
• Muscle cramps and spasms
• Headaches and fever

Professional Treatment Options

Doctors may administer several treatments for black widow spider bites. These options can include:

• Antivenom: A medical professional may use antivenom to counteract the toxic effects of the bite, depending on the severity of the symptoms.
• Pain relief and muscle relaxants: Over-the-counter pain relievers or prescription medications can alleviate pain, while muscle relaxants help with muscle cramps and spasms.
• Tetanus shot: A tetanus shot may be administered if the person hasn’t had one in the past 10 years.
• Monitoring and supportive care: Hospitalization may be necessary for severe symptoms or if an allergic reaction occurs.

Home Remedies

While waiting for medical help or if symptoms are mild, follow these steps to alleviate pain and reduce the risk of infection:

1. Wash the bite area with soap and water to clean the wound and prevent infection.
2. Apply an ice pack to the bite area to reduce swelling and numb the pain.
3. Elevate the bitten area to decrease swelling.
4. Take over-the-counter pain relievers like ibuprofen or acetaminophen to manage pain.
5. Use antihistamines (such as diphenhydramine) to help with itching and inflammation.

Prevention Tips:

• Wear gloves when handling firewood or working in areas with rocks, leaves, or debris, as black widow spiders might be hiding there.
• Check shoes, clothes, and garages for spiders before use.
• Keep outdoor sheds, woodpiles, and basements clean and free of clutter.

Comparing Black Widow and Brown Recluse Bites

Remember, always seek professional medical help after a venomous spider bite, and use home remedies only as a supplement to professional care or as an immediate intervention while waiting for help.

Prevention and Caution

Avoiding Black Widow Spider Habitats

Black widow spiders are known to inhabit dark, enclosed spaces like garages, sheds, and basements. Keep aware of these areas and keep them clean to limit the spiders’ presence.

They also tend to hide in rocks or piles of rocks, so be cautious when handling or moving such items outdoors.

Dressing for Protection

When entering or working in areas where black widow spiders may be present, it’s essential to dress appropriately with protection in mind. For instance:

• Wear long sleeves and pants to cover exposed skin.
• Put on shoes that fully cover your feet.
• Use gloves when handling items in spider-infested areas.

By doing this, the risk of suffering a spider bite can be minimized.

Handling Items in Spider-Infested Areas

In case you encounter a black widow or brown recluse spider, always exercise caution when handling items. Some suggestions include:

• Wear gloves for added protection.
• Shake off objects like shoes or clothing before using them.
• Use a tool to move objects when possible, creating distance between you and the spider.

• Both spiders can deliver painful and potentially harmful bites.
• Taking the same precautions for both can greatly reduce the risk of being bitten.

Conclusion

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about black widow spiders. Scroll down to have a look at some of them.

Letter 1 – Brown Widow Spider

Black widow??? Not sure…
Hey Bugman…
I was diligently cleaning off a table on the patio when I came across what looks to be a black widow – but I am not certain because of the color and markings on the back.

I saw the “hour glass” shape while it was pretending to be dead, but the spots when it flipped back over. I have come across this type of spider previously in another part of So. GA. Are you able to identify? Thanks!
Amy

Hi Amy,
This is the not quite as famous first cousin of the Black Widow, known as the Brown Widow, Latrodectus geometricus. BugGuide notes: “The brown widow is highly variable in color. It may be almost white to almost black.

Typically, it is a light to medium brown, with an orange-to-yellow hourglass marking on the underside of the abdomen; the coloration of the hourglass often is a good indication of this species. The leg segments are banded, with one half of each segment lighter in color than the other half. The back often has a row of white spots (rarely orange or light blue), and there are a few white stripes on each side. Darker individuals lack these markings and are difficult to distinguish from black widows.

” This is an introduced species and according to BugGuide, it is found: “World wide in the tropical zone. It was introduced in Florida and has since been observed moving north through Georgia, and into South Carolina; it has also been officially recorded in California, Alabama, Mississippi, and Texas. ” Your photo also documents this behavior noted on BugGuide: “Brown widow spiders usually curl up into a ball, and drop to the ground as a primary defense. It is highly recommended that people leave this spider alone; observe, but don’t touch. “

Letter 2 – Black Widows

Black Widows
July 16, 2010
Location:  Tx & Ar
I’m wondering if there is a season for Black Widows, the first pic I’m attaching is from Heartland, TX (SE of Dallas) 7/3/2010 & the second is from Little Rock, AR 7/16/2010, just seems to be that we’re seeing a more than usual. I say that but I’ve never seen one before a couple of weeks ago!
Thanks, Lisa

Hi Lisa,
In warmer climates, Black Widows can be found year round, but sightings will probably be more common during the warmer months when the spiders are more active.  Mature females will probably be most common toward the end of summer and into autumn. 

The specimen for Arkansas is not mature.  The coloration of a mature spider does not contain the red markings on the dorsal surface.  Though these sightings were in southern states, we believe both are the Northern Black Widow, Latrodectus variolus.  Your photo of  the immature specimen matches an image of the Northern Black Widow posted to BugGuide.

Letter 3 – Brown Widow Spiderlings

Subject: Daniel – Baby Orb Weavers?
Location: Hawthorne, CA
December 4, 2012 2:01 pm
Hi,
There are many, many, many of these little babies on the wheel barrow this morning. Are they orb weavers?
Signature: Thanks, Anna Carreon

Hi Anna,
The appearance of these Spiderlings and their presence on a wheelbarrow caused us to speculate that they were hatchling Brown Widows.  This image from BugGuide confirmed that speculation.  BugGuide states:  “Found around buildings in tropical climates.(1)

However, it is an introduced species and is the most human-adapted of the species occurring in the South Eastern US. Its webs may occur anywhere there is sufficient space to make one. It may be extremely abundant on houses and other man-made structures (e.g., barns, fences, guard rails, bridges). It reproduces frequently and disperses rapidly, making it nearly impossible to control.”  They are not as dangerous as the Black Widow, and BugGuide notes: 

” It is recognized that this particular species of widow is most likely not medically significant (not an immediate medical concern to those who are bitten). (Net Ref (4)) The brown widow produces clinical effects similar to that of the black widow but the typical symptoms and signs being milder and tending to be restricted to the bite site and surrounding tissues.”

Oh, my.  Thanks very much.  They’ve now dispersed, but I’ll be sure to keep an eye out for them!
As an aside, I just counted 16 Monarch caterpillars.
Anna

Letter 4 – False Black Widow

Subject: Male black widow?
Location: Squamish, B.C.
March 10, 2013 2:48 pm
Hello,
I found this spider in my garage. After photographing it, I took him on hike into the woods. I released him into an area with lots of downed trees/logs and leaves.
Is it a black widow?
Thank you!
P.S– In the first photo, he is playing dead because I put a cup over him (I think I startled/scared him).
Signature: Julia

Hi Julia,
We believe this is a False Black Widow, Steatodoa grossa, and according to BugGuide:  “The bite of this spider might produce symptoms that are similar but much less severe than those of a black widow bite. In some cases blistering may form at the site of the bite along with physical discomfort that lasts for several days.”

Letter 5 – Black Widow: Virgin Birth???

widow egg sac
Hi,
I wrote a while back and asked about keeping a young black widow I found in a box of supermarket firewood. I have had her now for several months, and have been keeping her in a container that has six 2-3mm holes for air. She’s quite happy –

I feed her all sorts of other bugs and sometimes pet store crickets. This morning I found her patting the last layers onto an egg sac – YIKES! How did this happen? Was it possible she had bred already, even when she was a wee cm long (including legs!)?

Or has she figured out how to bribe the cat to unscrew the lid to her bottle and goes out on the town at night? Hussy! In any case, what do I do now? Take it all out to the woods and let her go? I’d hate to have them running around the neighborhood – lots of little kids. here are a few photos of the little minx.
Thanks,
Syndi Burton
San Francisco

Hi Syndi,
First, we love your colorful letter. Minx is such an underused, descriptive word. We believe it is possible that your Elvira was fertilized prior to becoming your pet. She wouldn’t have begun to swell with eggs until she was well nourished, and we believe she probably had a more regular diet with you than she would have gotten in the wild.

It is also possible that the eggs are unfertilized and non-viable. To be safe, to the woods with Elvira might be the kindest solution to the riddle. Eric Eaton wrote in to add this: “Everything else looks in great shape:-) You are right about the female widow, by the way. Female spiders (and most insects, too) can store sperm from one mating and it lasts them a lifetime. Further, female spiders (and moths, etc) will lay eggs regardless of their viability, especially toward the end of the female’s lifespan.”

Letter 6 – Black Widows Mating

Black widows mating
You recently helped me identify this young male Black Widow. I caught him messin around with an older woman and thought you might like to add one of these to your Bug Love section. Thanks for your help.
Rus

Wow Rus,
Your photos just made our day. Thanks for sending these awesome images to us.

Letter 7 – Brown Widow

gold black widow???
Location: fontana, CA(50 miles from the coast, east of Los Ageles)
November 28, 2011 8:04 pm
Hello bugman,
I found this spider in my property it is the second one I’ve found. I did some research and it apears it might be an African species, it was hidding in a funnel like web, its cream color, and the hour glass underneath appears to be orange in color. Can you correct me in my identification? or did I got it rigth?
Signature: bajaboy28

Dear bajaboy28,
You are correct.  This is a Brown Widow, Latrodectus geometricus, a species native to Africa that has become naturalized in much of the southern portion of the United States.  According to BugGuide:  “Found around buildings in tropical climates.(1)

However, it is an introduced species and is the most human-adapted of the species occurring in the South Eastern US. Its webs may occur anywhere there is sufficient space to make one. It may be extremely abundant on houses and other man-made structures (e.g., barns, fences, guard rails, bridges). It reproduces frequently and disperses rapidly, making it nearly impossible to control.”  BugGuide indicates this about the bite: 

“It is recognized that this particular species of widow is most likely not medically significant (not an immediate medical concern to those who are bitten). (Net Ref (4)) The brown widow produces clinical effects similar to that of the black widow but the typical symptoms and signs being milder and tending to be restricted to the bite site and surrounding tissues.”

Letter 8 – Brown Widow bites woman eating grapes in Michigan

Subject: Found in grapes
Location: Southeast Michigan
June 1, 2017 7:28 pm
My wife was bitten in the finger as she was packing some grapes in a bag. We live in southeast michigan but not sure where the grapes come from
Signature: Bill Lowry

Dear Bill,
This sure looks like an immature Brown Widow Spider, Latrodectus geometricus, to us, but viewing through the plastic bag is somewhat distorting.  Here is a BugGuide image for comparison.  The Brown Widow is a recently introduced species According to BugGuide: 

“World wide in the tropical zone. It was introduced in Florida and has since been observed moving north through Georgia, and into South Carolina; it has also been officially recorded in California, Alabama, Mississippi, and Texas.”  If the grapes were imported from California, it is entirely possible that a Brown Widow was imported with them. 

BugGuide also notes:  “Widow Bites:  NOTE: It is recognized that this particular species of widow is most likely not medically significant (not an immediate medical concern to those who are bitten).  The brown widow produces clinical effects similar to that of the black widow but the typical symptoms and signs being milder and tending to be restricted to the bite site and surrounding tissues.  

Brown widow spiders usually curl up into a ball, and drop to the ground as a primary defense. It is highly recommended that people leave this spider alone; observe, but don’t touch.  The brown widow is an extremely timid spider which has rarely been reported to bite.”

Letter 9 – Brown Widow doused with aerosol insecticide

Great Site for Science Students
Wed, Jul 8, 2009 at 4:43 PM
Hi Bugman,
I’m a sixth grade science teacher and I wanted to say how helpful your site is when teaching my students about helpful and harmful insects, arachnids, and other creatures. Students love the pictures and they often have good discussions about the bugs I show them.

Your site is useful in helping students to identify before they kill bugs. Thanks for providing a great site. It’s great to show my students great pictures. You are appreciated!
C.G
Science Teacher
Florida
P.S.
I have enclosed a photo of a brown widow that I necessarily had to carnage on my front porch. It had nested under a chair on my front porch.

Dear C.G,
Thank you so much for your kind letter.  It is with trepidation that we are NOT tagging your letter as Unnecessary Carnage, and we feel many of our readership will disagree.  Your justifiably dispatched photo of a Brown Widow doused with insecticide nicely shows the typical orange coloration of the hourglass and the striped legs. 

According to BugGuide the Brown Widow has a distribution:  “World wide in the tropical zone.  It was introduced in Florida and has since been observed moving north through Georgia, and into South Carolina; it has also been officially recorded in California, Alabama, Mississippi, and Texas. Habitat Found around buildings in tropical climates. (1)

However, it is an introduced species and is the most human-adapted of the species occurring in the South Eastern US. Its webs may occur anywhere there is sufficient space to make one. It may be extremely abundant on houses and other man-made structures (e.g., barns, fences, guard rails, bridges). It reproduces frequently and disperses rapidly, making it nearly impossible to control.”  Since it is an introduced species, we will be tagging it as an Invasive Exotic.

Letter 10 – Brown Widow eats Solifugid in Kenya

Brown Widow catches a solifuge
Location: Masai Mara, Kenya
January 11, 2011 11:44 pm
Hi Daniel,
A while ago, I sent you a picture of a tiny little solifuge that we weren’t able to identify. The other day, I watched the same solifuge (or at least one of the same species) running across the floor of my tent to the corner behind my toilet.

It was the wrong corner to run to, as there’s a resident Brown Widow (Latrodectus geometricus) that lives behind my toilet. This was the result. I got a few more pics, but they were all out of focus as I was to excited to hold the camera steady.
Signature: Zarek

Hi again Zarek,
Thank you for sending us documentation of this awesome Food Chain encounter, a Brown Widow ensnaring a Solifugid.

Letter 11 – Brown Widow with Egg Sac

Subject: Is this a Dangerous Spider – Sure looks like it to me
Location: West Los Angeles
July 10, 2017 5:39 pm
Hi Bugman,
As much as I love butterflies, I don’t get along with spiders. Can you please let me know if this one is dangerous?
These are the best pics Icould take, but if you enlarge them the spider is quite visible.
Thanks,
Signature: Jeff Bremer

Dear Jeff,
Both the Brown Widow Spider and her egg sac which are pictured in your image are quite recognizable.  According to BugGuide:  “The brown widow is highly variable in color. It may be almost white to almost black. Typically, it is a light to medium brown, with an orange-to-yellow hourglass marking on the underside of the abdomen; the coloration of the hourglass often is a good indication of this species.

The leg segments are banded, with one half of each segment lighter in color than the other half. The back often has a row of white spots (rarely orange or light blue), and there are a few white stripes on each side. Darker individuals lack these markings and are difficult to distinguish from black widows. If an eggsac is present, this is the best identifying characteristic.

Brown widow eggsacs are tan, spherical, and have many small tufts of silk sticking out from them. They resemble a ‘sandspur.’ The other widows make white, smooth eggsacs that tend to be pear-shaped. ”

BugGuide also provides this information:  ” Widow Bites:  NOTE: It is recognized that this particular species of widow is most likely not medically significant (not an immediate medical concern to those who are bitten). The brown widow produces clinical effects similar to that of the black widow but the typical symptoms and signs being milder and tending to be restricted to the bite site and surrounding tissues. (Print Ref 1) 

Brown widow spiders usually curl up into a ball, and drop to the ground as a primary defense. It is highly recommended that people leave this spider alone; observe, but don’t touch.  The brown widow is an extremely timid spider which has rarely been reported to bite.” 

The Brown Widow is a non-native, introduced species that has gotten quite common in Southern California as well as the entire southern portion of the U.S.

Thanks Daniel,
It’s hard to know when to be worried and when not.
Jeff

Letter 12 – Brown Widow Egg Sacs

Subject:  What’s in my web?
Geographic location of the bug:  Camarillo, Ca near succulents
Date: 05/07/2018
Time: 07:53 PM EDT
Your letter to the bugman:  Dear Bugman,
I was outdoors enjoying some fresh air and succulents  and noticed a pretty substantial spider web plus these very interesting white spiky spheres. I’m wondering if you can identify them?

How you want your letter signed:  Melanie on the Irish Chain

Dear Melanie on the Irish Chain,
These are the Egg Sacs of a Brown Widow Spider, a species recently introduced to North America from Africa.  The Brown Widow is a relative of the native Western Black Widow, and since the introduction of the Brown Widow, populations of native Western Black Widows seem to have diminished, perhaps being displaced by a more competitive relative.

Letter 13 – Brown Widow in Mt. Washington

25 June 2012
Yesterday while cleaning off the patio furniture, we uncovered this Brown Widow‘s Lair under the rear right leg.  to be continued …
We did not realize she was there until a spray from the hose onto what we thought was an abandoned cobweb caused her to scuttle along a stand of silk revealing her orange hourglass marking.

The Brown Widow, Latrodectus geometricus, is also known as the Geometric Button Spider or the Brown Button Spider according to BugGuide, which lists its identifying features as: 

“The brown widow is highly variable in color. It may be almost white to almost black. Typically, it is a light to medium brown, with an orange-to-yellow hourglass marking on the underside of the abdomen; the coloration of the hourglass often is a good indication of this species. The leg segments are banded, with one half of each segment lighter in color than the other half. The back often has a row of white spots (rarely orange or light blue), and there are a few white stripes on each side.

Darker individuals lack these markings and are difficult to distinguish from black widows. If an eggsac is present, this is the best identifying characteristic. Brown widow eggsacs are tan, spherical, and have many small tufts of silk sticking out from them. They resemble a ‘sandspur.’ The other widows make white, smooth eggsacs that tend to be pear-shaped.” 

The little lady we uncovered had several egg cases.  BugGuide also notes:  “Found around buildings in tropical climates.(1) However, it is an introduced species and is the most human-adapted of the species occurring in the South Eastern US. Its webs may occur anywhere there is sufficient space to make one. It may be extremely abundant on houses and other man-made structures (e.g., barns, fences, guard rails, bridges). It reproduces frequently and disperses rapidly, making it nearly impossible to control.”

Though we see Black Widow’s with some degree of frequency around the offices, we haven’t noticed any in recent years.  We can’t help but wonder if our local species is being displaced by this recent introduction.  While the Black Widow’s bite is often regarded as potentially dangerous to sensitive individuals, the Brown Widow’s bite is generally not as serious. 

Here is BugGuide‘s assessment:  “It is recognized that this particular species of widow is most likely not medically significant (not an immediate medical concern to those who are bitten). (Net Ref (4)) The brown widow produces clinical effects similar to that of the black widow but the typical symptoms and signs being milder and tending to be restricted to the bite site and surrounding tissues.”

We would still caution readers to avoid Brown Widow as the bite might still be unpleasant if not dangerous.

Letter 14 – Brown Widow Spider, we believe

Easter Egg Spider
Location: San Fernando Valley, California
April 25, 2012 3:33 am
This little lady – I’m assuming its a lady – interrupted our Easter festivities. After a good deal of floundering and some heebie jeebies (I don’t have a good relationship with spiders) we managed to shoo her off into the garden.

We’re curious to what she is, though, she almost looks like an Easter Egg herself. I have not tried searching the internet because I am arachnaphobic.
Signature: Cautiously Curious

Dear Cautiously Curious,
In our opinion, this is a Brown Widow, an introduced species that might bite, though it is not considered as dangerous as the Black Widow.  See BugGuide for additional information.

Thank you for the quick response. There was an orange hourglass on her side – one of us wondered if she was an albino black widow, but that didn’t seem right. I’d never heard of brown widows before – looks like we’re lucky she put up with our efforts to move her, even if she’s not as lethal as a black widow.

Letter 15 – Cobweb Spider in Massachusetts

Subject:  Not a black widow, or is it?
Geographic location of the bug:  Apartment in eastern Massachusetts
Date: 10/17/2017
Time: 07:04 PM EDT
I found this odd looking spider in my apartment. My first thought was black widow, given its shape and the pattern on its back, but the coloration is different. What is this spider?
How you want your letter signed:  Joe

Dear Joe,
Though your image is quite blurry, we concur that this does look like a Widow in the genus Latrodectus, and we believe it might be a highly variable Brown Widow, a species recently introduced from Africa.  According to BugGuide data, it has been reported from nearby Maryland, and in Southern California in recent years it has nearly supplanted the native Black Widow.   While we entertain that possibility, we think this is more likely a harmless member of the Cobweb Spider family, like possibly Steatoda triangulosa which is pictured on BugGuide.

Update:  October 22, 2017
Thank you. We’ve gotten a picture of one of these spiders’ underside and observed their behavior a bit. They’re aggressive if their webs are disturbed, and roll into a ball if they fall. The webs themselves are messy and thee-dimensional, but not really funnel shaped.
Does this affect the identification?
Joe

Hi Joe,
We agree with Cesar Crash who provided a comment that this is NOT a Brown Widow, and most likely a harmless Cobweb Spider.  Your new image confirms that conclusion.

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Dinner Time!!

Black Widow dining on a Jerusalem Cricket
We found these guys hanging from the garage door when we got back to Los Alamos, NM from our vacation. The black widow was about the size of a silver dollar with legs. They really like our garage.I’d never seen a child of the earth before in my life though, and I’ve lived in this state for about 25 years. Well, I thought it was artsy at least. I wouldn’t have bothered snapping a photo had I never seen your web site!
Neale

Thanks for the photo Neale,
We have an old spider book by Gertsch that has photos of a Black Widow and a Jerusalem Cricket. It’s just not a fair match.