How Do Spiders Die Naturally? Science, Facts, Tips


So, how is your spider going to die naturally? Well, clearly we aren’t talking about ways in which it will die naturally, as we are going to just state that it’s all to do with old age. But what actually happens to them? Well, that’s easier to explain.

As a spider is dying, it goes through several processes which then leads to the familiar pose of it partly curled up. It’s organs will slowly shut down, and then it will end up in a ball, often appearing smaller than it did when it was alive.

But how does it get to this stage where it appears to be reduced in size? That’s what we are about to explain, and it’s all connected to how the entire body of the spider actually operates.

Dead spider on a web

How Long Do Spiders Live For?

So, let’s begin by discussing lifespan. This is tough to answer, as with over 38,000 species, the lifespan of a spider does vary by a huge amount.

Look at a female Tarantula, for example.

She can live up to 20 years, but then the male is going to live for around 7 or 8 years, and that’s a huge difference.

They aren’t the only ones that can have such a large difference in lifespan either. [Source]

In general, a spider is going to live for around 2 years, and that’s not too long in our eyes, but it feels like a lifetime for the spider.

It’s also worth noting that a number of male spiders will reach maturity at 2 years of age, go and mate, and then die. It seems that this mating thing is their final act as a living spider.

Thanks to this, it makes sense that the female is going to live a bit longer, but then they are still going to go through the same dying experience, no matter their sex or how old they are. So, what happens?

What Happens When Spiders Die?

Let’s forget about the various ways in which a spider can die, and look at what happens when it’s happening in the natural way. When this occurs, all spiders are going to actually die in the same manner.

Now, remember that your spider has various internal organs in order to live and survive. This clearly includes a heart, but then you have other body parts, such as muscles and blood flowing around to keep everything working.

Of course, that then comes to a grinding halt when they die, but then something rather interesting happens.

However, we will get to that interesting part shortly.

The length of time it takes a spider to die is also something we are unsure of. We don’t know if it’s a long, slow process of them dying naturally, or if it comes quite quickly.

What we do know though is that the body goes through a shutting down process bit by bit. Various parts of their body start to fail, resulting in a drop in blood pressure, and that’s when things get pretty serious for the dying spider.

So, onto that interesting part.

Their Legs

Have you ever noticed that a dead spider curls up its legs? There’s a very good reason for this, and it’s all thanks to the mechanics of a spider and how they manage to operate all those 8 legs when alive.

To understand this, you need to think about their legs as working with some sort of hydraulic system.

This hydraulic system is actually constructed of loads of small muscles that work in tandem with one another to allow those legs to move. [Source]

The muscles work by the spider having small spikes in their blood pressure, which causes them to flex. That then allows them to move their legs in the same sort of way as we can use our own muscles.

Also, this is what allows the legs to stay out all of the time. Those muscles really do operate in the same manner as our own ones that allow our arms or legs to stay as they are, and ready to be used whenever we want.

But that’s where the problem occurs when they die.

You see, the key in what we just said was talking about blood pressure being used to make the muscles move. But when a spider has died naturally, it doesn’t have that blood pressure in order to be able to do that.

So, what then happens is that those muscles stop working. The spider will, understandably so, lose the power and tension in those muscles.

As they die, they can no longer keep their legs stretched outright as the power supply is being shut off.

Basically, that then leads to the spider curling up its legs resulting in the pose that will be familiar to anybody that has set eyes on a dead spider at any point in their life.

Dead tarantula

Do Spiders Always Die On Their Backs?

Now onto another slightly different question, and that is whether or not a spider is always going to die on their back?

This is a misnomer, and it’s because people do tend to see spiders lying on their back when dead. This then leads to them believing that they go onto their backs in order to die.

Well, it turns out that this is not actually the case.

What happens is this.

As we just described, the spider loses its hydraulic power in its legs, and they curl up. They basically lose balance, and it tends to be the case that their back is the heaviest part of their body. This weight distribution is what then makes them fall onto their back when dead, as gravity takes its toll.

So, it’s not the case that they go onto their back and die. Instead, they die and fall onto their back.

The Part After The Hydraulic Failure

After the hydraulic failure has led to their legs curling up after death, the rest of the dying process takes place.

This is where the spider becomes dehydrated and their entire body shrinks in size. Of course, this is not unique to the spider and is commonplace with every single living thing.

However, for some reason, we notice it more with a spider. Perhaps it’s because of the amount that they shrink when their body dehydrates.

Also, their color changes as they dehydrate. They lose some of their luster, no matter what color their body was when alive, and that’s one of the parts that gets us when we see a dead spider.

What About The Spider’s Skeleton That We See?

Finally, what about the skeleton you see of a dead spider once it has been in that state for some time?

Well, as the insides have decayed, what you see is the shed exoskeleton and nothing else. That takes longer to basically decay away, so we see this shell of what used to be the spider.

So, the Conclusion

So, when a spider dies, it loses power in its legs resulting in it curling up into a ball. It loses power in the same way as we do when we die, just we don’t do the curling up thing.

Also, it dehydrates and shrinks in size as the spider version of rigor mortis sets in.

Ultimately, it leave us looking at that shed skin as a sign of what used to be a spider. As the owner of a pet, it’s a sad moment, but then you will have probably dealt with the dead body of your pet spider long before it gets to this part, and that’s why you will never really set eyes on it at home.

Well, apart from those house spiders that tend to run around at various times.

Barry Gray

Barry is a freelance writer from Scotland. He has written about pets for over a decade, and his work has been turned into a range of ebooks, courses, and material for diplomas. Barry is passionate about all animals, but particularly dogs, fish, rabbits, birds and spiders. You can find out more about Barry at https://mercurypets.com/our-writers/

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