Nostril width is linked to climate, and the wider your nostrils, the steamier the land where your ancestors evolved, according to researchers from Pennsylvania State University.
After 3D-scanning the noses of more than 2500 people from various ethnic groups, researchers found the widest nostrils belonged to west Africans, and the narrowest to northern Europeans. Why these nasal nuances? The width of the nostrils may have evolved due to the different temperature and humidity faced by geographically distant populations.
Breathing through the nose air-conditions the breath before it reaches the windpipe and lungs, suggest previous studies. In the nostrils, small ridges covered in mucous, called turbinates, heat the breath to the temperature of the body and add water vapour in order to keep the respiratory system moist.
Narrow nostrils might lead to better air-conditioning in cold and dry climates, say the researchers, as narrow airways create more contact with the turbinates, heating and moistening the breath better than wider nostrils.