Why Do Humans Have Different Nose Shapes?

Fagjun | Published 2017-03-21 02:40

A study has found that humans have different nose shapes because of climate.

There has long been a theory that people with larger nostrils have ancestors that adapted to warmer environments. Meanwhile, people with narrower nostrils have ancestors that adapted to colder environments.

Of course, the shape of our noses are also genetic. Like other physical traits, we inherited the shape of our noses from our parents. However, a long process of adaptation to specific climates and environments sculpted our noses to what they are today.

To establish a link between different nose shapes and climate, a team of researchers measured the noses of 476 volunteers. These volunteers were of east Asian, south Asian, west African, or northern European descent. Their parents also lived in the region where their ethnic roots were originally from.

The researchers published their findings in the journal PLOS Genetics.

Different Nose Shapes and Survival

This diagram illustrates the variation in nose shapes according to regional climate. Each colored box corresponds to a region on the map as well as a specific nose shape. [Diagram by Arslan Zaidi and colleagues]

According to their findings, nostril width has a connection to climate, temperature, and humidity in the environment. Narrower nostrils help people adapt to colder, less humid environments. Wider nostrils, meanwhile, help people adapt to warmer, more humid environments.

We can also appreciate the shape of our ancestors' noses from a survival and reproduction standpoint. For example, people who had long, thin noses with narrow nostrils had better chances of survival in cold and dry environments. This is because the shape of their noses made the air warmer and more humid once they breathed it in. This probably helped those people survive in their environment and thus gave them a better chance of reproducing.

Of course, nose shapes have variations even within the same ethnic population. The researchers say that sexual selection also played a role in the different nose shapes we see today. Arslan Zaidi, one of the researchers, also noted that there are more similarities in nose shape within the same population than there are differences.

An Oversimplification?

However, this study does have its limitations. For one thing, it only evaluated the external structure of the nose. It didn't evaluate the internal workings of the nose, like how it facilitates airflow or how it humidifies air. The researchers themselves admitted that their study may be a bit of an oversimplification. However, what they sought to illustrate was how humans adapted to different environments and how adaptation affected physical traits. Sexual selection may have influences the different nose shapes we see today, but the need to adapt and survive also played a role.

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