I am just amazed at how diverse life is on earth. And some of the more fascinating ones are the groups of Arachnids which are commonly known as spiders.

Just like the Praying Mantis and Dragonfly, Spiders have very intricate, if not beautiful, structures. And if that isn't enough, their hunting style is a bit more on the refined side.

But many people find spiders to be revoltingly ugly with their alien appearances. Eight eyes, hair all over, and thin legs supporting a large fat belly isn't visually appealing.

But if you take a closer look, you might find that they have a lot in common with a dish we find in most households – the tasty crab.

And maybe, just maybe, after looking them a little longer, you'll find they aren't disgusting creatures after all. You might even find them to be fascinating.

Now before you proceed, I must warn you that there are several pictures of spiders, as well as their parts, scattered about this article. If you're squeamish about that, you might want to check out our article on Golden Retrievers instead.


After seeing so many spiders in gardens and crabs on beaches, I have always wondered if they are related.

So I combed through the internet for hours just to satisfy my curiosity. I even went through an old book I had as a kid. It was one of those hand-drawn books, which ended up being colored by bored kids.

[Eh, was that me who colored it blue?...]

What I found surprised me. It turns out that both Arachnids, which are spiders, and Crustaceans, which are crabs, belong to the Phylum Arthropoda.

[A whaaaaat?]

Yes, both spiders and crabs are arthropods because they have external skeletons.

[Okay people, it's time to put on your thinking caps people because the geek speak's gonna get ugly for a while...]

But wait, there's more! Not only do they both have external skeletons, there are other similarities that make them look related.

Who's Who

Before we look at their similarities, let's first define who we are talking about, shall we?

When we talk about Arachnids, the type of animals we refer to include spiders, scorpions, ticks, and mites.

[No, Spider-man isn't part of that group; wise guy...]

In the case of Crustaceans, we think of lobsters, crayfish, shrimp, and crabs. And included in the list of different crabs are our very own Hermit Crabs.

[No, politicians don't fall under this group; good thinking though...]

Now that we know what we're talking about, let's jump into what makes them similar.

External Skeleton

Humans have internal skeletons in the form of bones. Just like the ribs in an umbrella or the trunk of a tree, everything soft gets anchored to this rigid structure.

Without bones, humans would just be a pile of muscle just like a worm. Without ribs an umbrella wouldn't open and would be more like a blanket to protect us from the rain. And without a trunk, trees would probably look like soft grass.

[Okay, so grass can stand because of a stalk, but you get the picture...]

In the case of spiders and crabs, they don't have any bones like human do. The counterpart of their bones are the shells that surround them.

In the case of crabs, these are hard shells that require dinner mallets to break open. And in the case of spiders, these are the shells that make that crackling sound when squashed.

They're kinda like your iPad or Digital Single Reflex camera with their hard outer shells made of Aluminum and Magnesium designed to protect the delicate electronic insides.

And since their skeletons are external, they also double up as armor for these critters.

[You still with me so far?...]

Segmented Body

Unlike the single, seamlessly flowing body of the a Ferrari F12 Berlinetta, the bodies of Arachnids and Crustaceans are made of several parts joined together in a not-so-seamless manner.

Think of Optimus Prime when he is in truck form. When not transformed, he is actually composed of two main parts – the cab and the trailer.

Spiders are the same because their head is the equivalent to the cab, while the body is what would pass for the trailer.

In the case of crabs, they are composed of three sections, one more than spiders.

[Medical break: Blink if you can hear my fingers snapping...]

Jointed Appendages

Now that you can picture segments as being individual parts, you need a way to move them around, right?

I mean, if a spider was just a head and a body without legs because it just won't do anything.

[Heck, it couldn't even use a remote to change channels this way...]

So to keep it from becoming nature's couch potato, evolution decided to stick a few appendages so it doesn't end up being lazy.

And since Mother Nature was the first to lay down the design rules that were later adopted by Pininfarina in designing Italian cars, she kept things consistent. With the body covered in armor, that meant the legs and other parts have to be encased in armor too.

So legs were all bolted on by nature's tiny factory workers to come out with one of the deadliest hunters ever to walk and swim the planet.

[Medical break: Follow my fingers with your eyes...]


Alright! We're done with the geek speak. On with the show...

[Oh yeah, you can stop pinching your bleeding nose now.]

With that done, let's jump into the some of the reasons why spiders are truly fascinating creatures.

If Dragonflies are the fighter pilots and the Praying Mantids are the Kung Fu masters, Spiders are the Ninjas of the tiny world.

They are Fast

Spiders are patient and have the capacity to stay stationary for hours while lying in wait. However, they are capable to great speed once a potential prey has been spotted.

Using those eight tiny legs, it still surprises me how they can cover long distances in such a short time. And while humans can sprint pretty quickly horizontally, spiders have to content with moving vertically too.

But their speed is not limited to crawling along. For the more active ones, jumping great distances with nothing but a flick of its legs enables them to pounce on their prey without being seen.

They Have Venom

Just like Ninjas, spiders have a variety of weapons at their disposal. The most deadly is the venom they carry in small sacs in their heads.

Once prey is within striking distance, it only takes a split second for spiders to inject the venom through hollow fangs that can be extended and retracted at will. And after this is done, they simply fall back far enough while their victim succumbs to their poison.

They Spin Webs

Another weapon that spiders have at their disposal is the ability to spin threads of silk which they weave in to a web.

Contrary to popular belief, not all of the silk they create is sticky. The first type is normal non-stick silk, which it uses as a bridge to walk on or as a rope to slide down from. And the second type can be coated with drops of sticky fluid to entrap its victims that come in to contact with it.

When building a web to catch flying insects, spiders will sometimes come out with intricate designs that look invisible to insect eyes. However, to humans, these webs can look as beautiful as tiny string rainbows when sunlight strikes them.

They Sip Food

One of the major differences between spiders and crabs are that the former do not have teeth to chew their food with. While crabs eat by taking a bite from their prey, spiders can only consume liquid food.

As part of their design, the venom they inject includes digestive enzymes which liquify their prey so spiders can just suck it out like our couch potato does with his king-sized soda.

They Look Scary

While I love the large emerald eyes of Dragonflies and the long delicate stance of the Praying Mantis, Spiders have this terrifyingly menacing look about them.

With their multiple unblinking eyes, stiletto-like legs, and colorful bodies, spiders have that fearful but mesmerizing thing going for them.

Final Thoughts

Just like Dragonflies and Praying Mantids, Spiders are highly specialized killers who's main prey are the millions of insects in this world.

Without them, insects around the world take seconds to consume all the plants we rely on for food.

And if you thought that insects just fed on plants, consider that swarms of mosquitoes, horseflies, ticks, and other insects can take down full sized goats, cows, buffaloes, and even Golden Retrievers if left unchecked.

Spiders are invisible when stationary, a blur when moving, and carry an arsenal of weapons which they use with extreme precision. Yet, their delicate appearance belies this ability.

It is this marriage of being beautiful and lethal that fascinates me whenever I see one sitting in the middle of a web.

So the next time you happen to come across a spider patiently sitting in its web, give it a look. You just might be fascinated yourself.

Just don't look too long though. Some say that spiders have a hypnotic ability too. And you wouldn't want to wake up wrapped like a present while waiting to be someone's dinner.

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