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Black Widow vs Brown Recluse (Similarities & Differences)

The black widow and the brown recluse are the two most venomous spiders in the United States.

Black Widow vs Brown Recluse

Between the two, both are dangerous, but brown recluse spiders can cause more harm than black widows. In fact, 80% of brown recluse bites are considered serious. But deaths from either are very, very rare. More people die from dog bites and lightning strikes!

The main identifiable difference between a black widow and a brown recluse is that the black widow has a red mark on its abdomen and a shiny black body, while the brown recluse has an entirely brown body with a violin-like shape near its head.

Regardless, you wouldn’t want to be bitten by either of these two spiders, so making sure that you spot them early and avoid them would be one of the best strategies to avoid getting bitten in the first place.

In this article, we’ll take a look at the key differences and similarities between the black widow and the brown recluse.

Important Note: This is general information for entertainment purposes only. If you have been bitten, seek professional medical attention immediately. Always have professionals identify and manage your pest control needs.

Black Widow vs Brown Recluse

FeatureBlack WidowBrown Recluse
1. Scientific NameLatrodectusLoxosceles reclusa
2. Venom Venomous but rarely fatalVenomous but rarely fatal
3. Body Size (not including legs)3 – 13 mm6 – 20mm
4. ColorBlackBrown
5. PatternsRed hourglass mark on abdomen.Violin shape on upper back.
6. Where they LiveAll of USA and Southern Canada. Primarily concentrated in the South.Southern USA.
7. Web TypeTangled Web.Tangled Web.

Black Widow Spider Overview (Credit)

Brown Recluse Spider Overview (Credit)

Similarities

Here’s how the black widow and the brown recluse are similar.

1. Web Weaving

brown recluse

Both of these spiders are not particularly known for creating large, elaborate webs. Instead, they prefer to make smaller webs that appear asymmetric and untangled, although they don’t use them primarily for preying on other animals.

Instead, their web weaving is more aimed towards their survival rather than filling up their tummies. Both will create webs, but they won’t depend on them for survival primarily, because their venoms are potent enough to keep them protected.

2. Both are Venomous

Another key feature that both have in common is the fact that they’re both on the list of the most venomous spiders in the world. While their bites might not have caused that many deaths around the world, they can still be highly unpleasant and might have several negative consequences in the long term.

There has been just one report of a brown recluse death in the United states in over a decade and no reports of black widow deaths.

Even though no deaths have been reported in the United States because of black widow bites, there have been several reports of deaths because of black widows around the world.

It’s still better not to be bitten by either of these two than to risk the long-term health consequences their bites may have. That’s why recognizing the two species will be crucial towards helping you avoid these bites altogether.

3. Similar Size

brown recluse

Another feature that these two spiders have in common is the fact that they’re quite similar in size. Most commonly, both of these spiders will be between 6-10 millimeters (up to 0.5 inches) in size, which will make it slightly harder for you to distinguish between the two.

Their body structures are also quite similar. They don’t have that many hairs, which is why you might not see hairs on the bodies of these two spiders. However, it would be quite difficult for you to confuse these two spiders because the visual differences between the two should be quite obvious.

4. Similar Diet

Last but not least, we should also mention the fact that black widows and brown recluse spiders have a similar diet.

They’re both carnivores, which means that they prefer to eat insects and bugs as their primary type of food. They are also very good at eating animals that are larger than them thanks to their potent venoms.

Differences

So, what are the differences between a black widow spider and a brown recluse?

1. Visual Differences

First of all, the most obvious difference between the two is their appearance. The black widow has a distinct red mark on its black body, which is visible on its back.

This is the one mark that should make it much easier for you to see the differences between these two spiders.

Brown recluses, on the other hand, are entirely brown and they also often have a violin-shaped feature on the back of their bodies, near their heads. You should be able to tell the difference between the black widow and the brown recluse only by looking at their colors and their appearance.

However, many people still mistake the black widow spider with other black spiders, which is primarily because of their black appearance.

But if you’re still confused about the differences between the black widow and other black spiders, simply take a look at the mark on the body, which should be the easiest way to tell between a black widow and other black spiders.

2. Habitat

Black widows might enter your home, but that is not very common to happen. That’s because they’re not very comfortable entering your home, so they will usually not spend a lot of time in your home. They might create webs and spend some time there, but they’re not very comfortable doing that.

Brown recluse spiders, on the other hand, prefer to live in hidden areas and will make themselves at home if they happen to enter your household. They like dark, hidden corners of your home where they can stay comfortably without having to adjust too much. This means they’ll spend a lot of time under objects and hidden inside darker areas of your home.

The brown recluse will often also be found inside your clothing (which is how most bites happen). They like to hide in the dark protective cover of clothing that you have left on the floor overnight

3. Different Venom Effects

Both of these spiders are venomous and have the potential to cause serious damage to humans, which is why it’s better to avoid them altogether.

However, one of the key differences here is that they have different types of venom.

The venom of a black widow will cause systemic problems such as sweating, chills, nausea, dizziness, lightheadedness, and other symptoms that might be unpleasant, but should go away after some time.

On the other hand, the bite of the brown recluse is known for causing necrosis. This might cause a small percentage of brown recluse bites to cause our flesh to rot, which is unpleasant but might sometimes happen. This will happen in about 10% of all brown recluse bites.

Read Also: Do Black Widows Play Dead?

4. Webs

Black widows usually create tangled webs that they will hang upside down. The brown recluse, on the other hand, will still create tangled webs, but the purpose of these webs will be different.

The web of the brown recluse doesn’t have a particularly important role in catching other animals, as it acts as a protective measure for the spider. The black widow’s web, on the other hand, will sometimes be crucial in the pursuit of their targets.

Which is More Venomous?

Both are venomous, and they should be avoided if possible, although deaths from either are extremely rare. They can cause side effects like stomach cramps and vomiting.

The venom of the black widow is 15 times more potent than a rattlesnake. However, it usually doesn’t deliver enough venom per bite to kill a human. And in fact, the brown recluse bite tends to cause more serious harm.

Their venom types are also slightly different.

The venom of the black widow will mostly cause systemic reactions, which the brown recluse venom might also cause.

However, the venom of the brown recluse is known for causing necrosis, or permanent tissue damage. 

Deaths due to bites of these two spiders are very rare, though. In recent years, there have been no direct deaths caused by the bites of these spiders, which is mainly thanks to modern medicine, but also because people are more and more aware of the potential dangers of these bites.

Other Spider Comparisons:

Conclusion

In conclusion, the differences between a black widow and a brown recluse spider should be visible quite quickly. The main difference is their appearance, where the black widow is completely black with a red mark on its body, while the brown recluse is brown with a distinct violin-like shape near its head.

Both are venomous and potentially dangerous though, so it’s best to avoid them if at all possible!

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