Do Worms Have Lungs? (How Do Earthworms Breathe?)

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Worms do not have lungs as we do; however, their respiratory system is nothing short of incredible.

They are able to survive sometimes extreme circumstances by extracting oxygen from air pockets and wherever they can. 

However, as is the case with all living things, there are certain situations in which a worm cannot rely on their respiratory system to save them and where it is, in fact, their downfall. 

No, you won’t find lungs in a worm’s body. Earthworms use capillaries that line the outer layer of their skin to breathe, distributing oxygen into the worm’s bloodstream and circulatory system, all while releasing carbon dioxide. This process is called diffusion

Now you know there are ways for worms to absorb oxygen in order to breathe and survive.

In this article, we’ll find out in more depth how this works in a worm’s body and why it’s important for an earthworm’s skin to stay moist so that they can keep breathing.

How Do Worms Breathe? 

Unlike us humans and other animals, worms do not use their mouth (do worms have mouths?), nose, or lungs for breathing.

In fact, worms do not have noses, nor lungs.

They do have mouths, but even they are very different from our own (they have muscles in their mouths to consume their food instead of teeth). 

However, when it comes to breathing, they do not need to use their mouths at all. 

In fact, worms breathe through their skin.

That is why the right environmental conditions and oxygen availability are essential for their survival and to support worm life.

For those of us with compost piles, worm bins, or vermicomposting systems, we all know that keeping the containers moist is essential (as is heat control as worms have cold blood and can’t regulate their body temperature).

This is entirely for the worm’s benefit.

In a dry environment, the worms will not be able to move comfortably through the soil, but most importantly, they will suffocate from the lack of moisture, potentially dying if they cannot escape to a more suitable environment. 

You will have undoubtedly noticed in your lifetime that an earthworm’s body is pretty slimy.

That’s because that outer layer of slimy mucus on a worm’s skin is part of their respiratory system, and they need it to breathe. 

Your worms need to remain wet or stay wet within the soil they travel through.

But how does the oxygen penetrate the skin? 

How Earthworms Use Diffusion to Breathe 

In truth, the way that earthworms breathe is fascinating and key to understanding these little creatures a little better. 

The process that takes place is called diffusion.

Diffusion is the movement of molecules, in this case oxygen, from an area of higher concentration (the outside air or soil) to a lower concentration area (the earthworm).

Earthworms use capillaries that line the outer layer of their skin to breathe.

The capillaries on a worm’s skin manage to distribute oxygen into the worm’s circulatory system, all while releasing carbon dioxide out of the worm. 

That is why the outer layer of mucus on the earthworm is so essential.

The earthworms rely on the mucus to provide a passage through which a higher concentration oxygen can enter and the carbon dioxide can leave. 

This is also why we are always told to keep a worm’s environment moist.

If a worm gets too dry, the mucus on them will dry up to, therefore blocking the passageway for the oxygen and the carbon dioxide, so diffusion can’t take place.

That is why the worms prefer moist environments and die in the sun because it has suffocated due to the dryness blocking this process. 

Can Worms Breathe Underwater? 

Yes – worms can survive underwater, but you’ll notice in heavy rain, worms come to the surface.

This is because it’s a temporary measure. Worm’s can drown if they stay underground during hard rain.

While they can survive underwater longer than we can, as their skin can absorb the oxygen, eventually the worm will drown. This is thought to take around 30 minutes.

Although it’s thought that worms exit the ground when it rains due to their risk of drowning, this may not be entirely true according to another theory..(more on this below)

In fact, some studies have shown that worms can live up to approximately two weeks living underwater.

If the water has lots of air within, their respiratory system may allow them to use more oxygen from the water to survive. 

But it is also important to note that the worm will die after those two weeks, or even longer, depending on the worm. 

Worms cannot swim, as their bodies are only equipped with small bristles to burrow through the soil. 

You can learn more about earthworms crawling, how they move and do worms have bones?

Eventually, they will not be able to get the amount of oxygen that they need from the water, and they will drown. 

So, why do earthworms come out when it rains? Surely they would be better off avoiding the wet surface, large puddles and rain sweep? 

The other theory is that they come out to stop being hunted – recent studies have shown that while earthworms do leave the soil during rain storms, this may have less to do with the rain and more to do with what they think is a predator beneath the soil. 

During rain, worms feel vibrations in the soil that mean something to the worm.

The vibrations could be from a predator in the soil, moles specifically who live underground and love to eat them.

Therefore, staying underground is a bad idea in their mind and in order to avoid predators, the earthworm will rise to the surface of the soil in an attempt to hide from their chasers.

Can You Suffocate a Worm? 

As was mentioned, yes, you can suffocate a worm in multiple ways. 

When we get dehydrated, we can still breathe.

However, as worms need moisture to keep their bodies wet in order to breathe, being dry is a sure way for worms to suffocate as they have access to a lower concentration of oxygen.

In fact, a worm in direct sunlight with no means of getting wet will dry up, suffocate, and die within one hour. 

However, when it comes to water, worms are far more efficient than we are.

The average person will drown within a minute.

On the other hand, worms may take up to two weeks, and some even longer, to drown. 

However, it is essential to note that they are not able to survive full time underwater, and eventually, they will suffocate and die without fresh air.


While worms don’t have lungs, hopefully, you’ve learned the fascinating way in which earthworms absorb oxygen through their skin in a moist environment.

Make sure your worm’s stay moist, but a higher concentration of water may be detrimental to your earthworms.