Praying Mantis vs Black Widow Spider: Who Would Win in a Fight?

Written by Kyle Glatz
Updated: January 23, 2023
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Praying mantises are very interesting insects that are known for their folding raptorial forelegs and large size. Also, praying mantises tend to consume each other during the mating process. These insects face many cunning foes throughout their lives, and they specialize in eating arachnids. That begs the question of how they would fare in a battle between them and some of the deadliest spiders. Come along as we compare a praying mantis vs black widow spider and show you who would win in a fight!  

Comparing a Praying Mantis and a Black Widow

A black widow spider is more dangerous to humans than a praying mantis.
Praying MantisBlack Widow
SizeWeight: 0.14oz to 0.18oz
Length: Between 2.75 inches and 5 inches, but some grow upwards of 6 inches or more
Weight: 0.035oz
Height: 0.75- 1.5 inches
Phylogenic ClassInsectArachnid
SensesPoor hearing, but capable of sensing “ultrasound”, the echolocation used by predator bats
Great vision since they are the only invertebrate to see in 3D
– Smell is limited to pheromones from others
– Can sense vibrations in its web
– Poor vision
– Can smell through hairs on their legs and pedipalps
Defenses– Male praying mantises can fly, but females cannot
– Effective ability to dodge bats
– Camouflage  
– Web
– Speed
– Red hourglass shape on their bodies scares enemies in some cases  
Offensive Capabilities– Long, powerful, spiny forelegs help them trap prey
Powerful mandibles allow them to bite and consume prey
– Venomous bite    
Predatory Behavior– Ambush predator that seeks to trap and hold their prey while they quickly consume it  – Wait for creatures to disturb their web and then quickly attack them, wrapping them in silk    

What Are Key Differences Between a Praying Mantis and a Black Widow?

Animals with exosceleton black widow spider

Black widows are deadly arachnids that can even harm people.


The key differences between a praying mantis and a black widow include their phylogenic class, morphology, and size. Praying mantises are tall insects that reach heights of 6 inches and use their raptorial forelegs to attack prey, and black widows are small, web-spinning arachnids that grow a maximum of 1.5 inches in length and use their deadly venom to paralyze and kill foes.

The differences between these two creatures are quite noticeable. They’re from different families, hunt in a unique fashion, and have a massive size disparity. We’re going to consider these qualities and show you how these animals fare in a fight against each other.

Are Praying Mantises or Black Widow Spiders More Dangerous to Humans?

Apex predator: praying mantis

Praying mantises are dangerous to other insects but not to humans.

©Ryzhkov Oleksandr/

Black widows are far more dangerous to human beings than praying mantises. Unless the praying mantis is one of the largest members of the species, a human probably won’t even notice the bite. You may feel the pinch from the raptorial forelegs if it grabs you. You’ll also feel a pinch if its mandibles are large enough to bite your skin. However, it will not break your skin or cause you to bleed.

Black widow spiders can bite and inject their venom into human beings. Their venom is potent, but the amount they can inject at once is small. While rare, black widow bites can be fatal to human beings, but usually only for young, old, or unlucky individuals. These bites occur as a result of stumbling upon black widows; they do not hunt people.

If a healthy adult is bitten by a black widow, they can face some poor health outcomes. Usually, people deal with pain at the bite site, muscle pain, swelling, and nerve pain. Other symptoms include nausea, sweating, and difficulty breathing.

If you have the choice, it’s better to get bitten by a praying mantis or a male black widow than a female black widow.

What Are the Key Factors in a Fight Between a Praying Mantis and a Black Widow?

Australian Red-back spider

Black widows rely on their venom to kill other creatures.

©Peter Yeeles/

Like many other fights in the animal kingdom, a battle between a praying mantis and a black widow would boil down to a handful of factors. Size, combat abilities, speed, and other factors would play the largest roles in this fight. Let’s break down how each element would impact a battle between the two animals.

Praying Mantis vs Black Widow Spider: Size

A praying mantis is much larger than a black widow. Praying mantises can grow six inches tall and weigh about 0.2oz, but a black widow only grows about 1.5 inches in length and weighs about 0.035oz. Most of the spider’s size comes from their legs. The females of both species are larger than the males.

Praying mantises have a size advantage.

Praying Mantis vs Black Widow Spider: Senses

Both praying mantises and black widows have limited senses. Praying mantises use a form of echolocation and sight to find prey, but their sense of smell is underdeveloped. Meanwhile, black widows have a poor sense of smell along with the ability to sense vibrations very well.

Praying mantises have better senses.

Praying Mantis vs Black Widow Spider: Physical Defenses

Many creatures will avoid black widows for fear of their venom, but these spiders also have some speed and webs to help keep them safe. Praying mantises rely on their camouflage and quick reflexes. Males can fly for short distances, too.

Praying mantises have better-developed defenses.  

Praying Mantis vs Black Widow Spider: Combat Skills

Black widows are known for their deadly venom that can kill with a single bite. They will often wait for prey to trigger their web, get stuck, and then deliver a bite to neutralize their target. After that, they’ll wrap their prey in more silk and call it a meal.

Praying mantises uses incredibly fast reflexes to snatch up enemies with their raptorial forelegs and then chew them apart with their mandibles. This process is lightning fast and brutal.

Who Would Win in a Fight Between a Praying Mantis and a Black Widow Spider?

Praying Mantis, Mantis religiosa, eating a grasshopper.

A praying mantis would snatch up and dismember a black widow.


A fully grown praying mantis would win a fight against a fully grown black widow. Praying mantises are too fast for a black widow to counter. The fight would probably start with the praying mantis disturbing the spider’s web, and it would rush out to meet it.

Unfortunately, the mantis would swiftly grab the spider with its forelegs, preventing any escape and preventing the spider from biting. In a few seconds, the praying mantis would dismember and consume the spider with its powerful mandibles.

A black widow could score a pyrrhic victory by delivering a bite right before being devoured. Even then, it’s not going to win a fight outright.

The photo featured at the top of this post is © Karel Bartik/

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About the Author

Kyle Glatz is a writer at A-Z-Animals where his primary focus is on geography and mammals. Kyle has been writing for researching and writing about animals and numerous other topics for 10 years, and he holds a Bachelor's Degree in English and Education from Rowan University. A resident of New Jersey, Kyle enjoys reading, writing, and playing video games.

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