Why we have two nostrils if we only use one?


Have you ever wondered why we have two nostrils? If we really had two throats it would make sense, but if we only have one, why should we need a pair of nostrils?

It was this very question that prompted Stanford University’s Olfactory System Research Project to try to find an answer. And, thanks to the study they conducted, today we can give it to you.

So why two nostrils if we could perfectly well have only one?


We know why we need two ears. Thanks to the presence of two sound receptors, we have the brilliant possibility of locating the source of the sound more precisely. This way, in a matter of milliseconds we know if something has made a noise behind us, to the right, to the left or anywhere else around us. Having a pair of ears is also the explanation for the stereo effect.

The importance of having two eyes is also generally known. Thanks to them we can see in three dimensions and the depth of objects and images in front of us.

However… why we have two nostrils? Unlike our ears or eyes, we have only one nose, but with two nostrils. Two nostrils inside one nose.

Why can i only breathe through one nostril?


To answer this question we would have to go further, and see if two nostrils have any advantage over having only one. And the answer is yes. According to a study published by Stanford University, the nostrils alternate the work of smelling and breathing. That is, while one nostril is doing all the work, the other is blocked, and vice versa. Why does this happen?

We actually breathe through one nostril at a time. Sometimes we may feel during a day that one nostril is more open than the other and it is easier to breathe through that nostril than the other. No, this is not psychological. It really happens and it has a purpose. It is called the nasal cycle. During this cycle, one wall of the nose is more swollen than the other. This changes every 2-3 hours during the day.

Try it! Try breathing only through your right nostril and then only through your left nostril. You will quickly notice that breathing through one orifice is easier than another.

Why does it happen? You may or may not know, but the nose also acts as a filter. The nasal cycle means that one nostril breathes and transmits oxygen to the body and the other can cleanse itself of dirt. This enables our body to breathe and filter the air simultaneously. And that’s not all!

The nostrils are also important in recognizing different types of odors. We read that the nasal cycle is responsible for a better conduction of air to lungs, but it is also true that some types of odors are better recognized by one orifice, and other odors by other orifice. It is even said that some ingredients in the air are recognized if the air flow is slow and other times when it reaches the receptors very fast.


Finally, imagine how weird it would be to have only one nostril! Apparently having two nostrils is a pretty nifty idea, isn’t it?