Myth Busting – Breathing On Backs

We come across this one quite a lot online and so many people are of the opinion that this myth, about bearded dragons breathing on their backs – or rather not being able to breathe on their backs, is just a myth.

Many people take a lot of time to explain why they believe, in the absence of any scientific studies, why they don’t believe a bearded dragon cannot breathe on their backs.

Let’s unpick it shall we? Is it an old internet myth, or is it true?

Can Bearded Dragons Breathe On Their Backs

Along with the arguments about whether they can breathe on their backs or not, there comes the pedants who are quite happy with the notion that their bearded dragon won’t die if they’re on their back.

This may be so. Or it may not. We can’t find any studies that suggest they die or live if they are left on their backs. Maybe because a study of that nature would be pretty unethical, it serves no purpose and there’s ample other evidence that means bearded dragons don’t breathe effectively when on their back.

Let’s investigate the physiological reasons how we know that bearded dragons can’t breathe properly on their backs, without specific studies needed.

Bearded Dragons Have No Diaphragm

Veterinarians and other scientists who’ve dissected bearded dragons can be trusted when they tell us that bearded dragons have no diaphragm, so there’s no real need to argue this point. We know they don’t because there’s solid evidence they don’t.

But why is that an issue?

Diaphragms in mammals serve two semi-related purposes. The first we’ll look at is that the diaphragm keeps the thoracic structures separate from the abdominal structures. It forms a reasonably strong barrier against the two areas from interfering with each other. In so doing it also increases the efficiency of the intercostal muscles (the muscles which lift and expand the rib cage) by reducing the volume the intercostals have to interact with in order to inflate the lungs. A larger relative volume requires a larger change in size to cause a pressure decrease, particularly if only part of that volume is able to expand.

A bearded dragons anatomy and physiology is setup to work most efficiently when it’s four legs are on the floor. Abdominal structures sit in the correct place, and don’t interfere with the position of the lungs. On their backs however, those abdominal structures end up moving upward and backward and restricting the room available for the lungs, with no diaphragm to prevent the structures interfering.

Reduced lung volume leads to more difficulty breathing.

Secondly, the diaphragm is an extremely efficient way of helping to inflate the lungs and if bearded dragons had one, then even if they could not move their ribcage at all, they could still breathe on their back by contracting their diaphragm, pushing the abdomen out (instead of the ribcage) and drawing air into the lungs that way. But they don’t have a diaphragm so they cannot do that. In humans we sometimes refer to this process as ‘abdominal breathing’ – but in beardies it can’t be done.

Bearded Dragon Lungs Expand Differently To Ours

In humans, the lungs expand primarily upward towards the head, and outward towards the front. The more mobile part of our rib cage is at the front or ventral aspect. Because of the fact that bearded dragons are normally in a horizontal position, their rib cage is optimised for their horizontal, belly downward position. Watch your bearded dragon breathe when it’s in its normal position with feet on the floor and you’ll see their sides expand outward and their rib cage show through their back as the ribs push upwards toward the sky.

This expansion of the ribcage in the normal position is relatively straightforward because there is little weight to move out of the way. The only resistance to expansion is the (somewhat small) weight of the ribs themselves and the compliance (stretchiness) of the skin on their back and the lung tissue itself.

The sternum and other weight of the lungs is normally kept mostly off the floor by the front legs when the bearded dragon is the right way up – but this is not the case on their back.

A bearded dragon on its back has to use its intercostal muscles (the muscles that pull the ribcage up and out) to lift the entire weight of it’s lungs, front legs and those extra abdominal organs that have now migrated, in order to expand the lungs.

If it had a diaphragm the extra weight of the abdominal organs could be somewhat offset by pushing them back down to where they belong.

On its back, the bearded dragon also has to overcome the friction associated with the ribs at the back being pushed into the surface of the floor. In other words, the intercostal muscles have to work considerably harder to achieve the same result. This results in extra oxygen being used just to breathe and so, the lizard has to breathe more, just to provide enough oxygen to breathe. It’s a bit of a vicious circle this.

Bearded Dragons Do Not LIKE Being Upside Down

Now add into the equation that the bearded dragon is a wild animal without much (if any) ability to reason things through, and understand that in this position the bearded dragon belly is facing upward. That soft underbelly that has limited protection against birds or other predators. And with legs in the wrong position, the bearded dragon is vulnerable. They begin to panic. Which releases catecholamines such as adrenaline – which makes the heart beat faster and uses therefore more oxygen. They struggle, moving legs frantically – using more oxygen.

More oxygen demand on a system less able to deliver it, leads to hypoxia and hypercapnia. Which leads to more panic. Another positive feedback cycle that is a vicious circle.

But Vets Operate On Bearded Dragons On Their Back

We’ve heard this time and again as an excuse for why people can handle their bearded dragons poorly by laying them on their back to take photos or do something else pointless.

Yes, veterinary surgeons will, if necessary, lay a bearded dragon on its back while they perform surgery. But the argument that vets do this, therefore beardies must be OK on their back neglects one crucial feature.

During an operation a bearded dragon is anaesthetised and does not breathe for itself at all in many cases. Often, either a veterinary assistant will be breathing for the dragon or it will be hooked up to machinery which breathes for it. The physics involved in breathing is very different when a machine is doing it for you. We could go into detail about negative versus positive pressures for inspiration, but you can look that up for yourself if you need convincing.

Test It For Yourself (And On Yourself)

If you’re still not convinced, try this experiment. It’s not particularly scientific but it’ll give you an idea about how it works.

Sit in a chair, with good posture – straight back etc. Take some deep breaths in and try not to expand your stomach while doing so because that’s your diaphragm at work. Just use your ribs to breathe whilst in the chair.

Now, lay down on the floor on your stomach, facing the floor. Don’t lay on cushions or the bed, the hard floor is most effective for the demonstration. You can tilt your head slightly to the side to avoid squashing your nose and causing pain to yourself of course. Don’t try this if you already have breathing troubles or have mobility issues and will find it difficult to get back up off the floor afterwards. Preferably make sure someone is with you so you can get help if you need it, though you should be fine.

Now you’re on your front on the floor, try to breathe in using just your ribs again. No cheating – using your diaphragm is cheating because bearded dragons don’t have a diaphragm. If you’re honest with yourself you should notice that it’s quite a bit harder to breathe when your chest is pressed against the hard floor. This is how it is for your bearded dragon on their back.

Will Bearded Dragons Die If They’re On Their Back

Well that largely depends on why they’re on their back. But whilst they may not die from breathing troubles on their back – there are plenty of reasons why it’s certainly much harder for them to breathe on their back, so any deliberate prolonged activity that keeps them on their back should be avoided.

They don’t like being on their back – and if you find yours is flipping onto its back regularly you may have other, neurological problems to deal with instead. If you’re regularly finding your bearded dragon on their back you need to strongly consider an urgent vet consult.

Summary

Many people claim that there’s no scientific evidence that bearded dragons can’t breathe on their back, because there’s no studies that support it. We note there are no decent scientific studies on the efficacy of parachutes at saving humans who are falling from airplanes. Why? Because sometimes a randomized double blind trial is just not needed to arrive at a solid conclusion which can be more easily found through other, less dramatic evidence.

Understanding the anatomy and physics of breathing is enough to understand that bearded dragons find it harder to breathe on their back versus their front. Whether they will eventually suffocate or not from it isn’t known by us because we’ve never tried. Even if you don’t understand the anatomy and physiology of breathing, it’s clear that bearded dragons do not like being on their back, so why even put them in that position?

Our view is that bearded dragons cannot breathe properly on their back and we suggest it is not a myth but is in fact true, backed up by science and engineering principles.

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Featured Image by HIROMASA HADACHI from Pixabay