Shape of Human Nose Influenced by Climate

The basic function of the human nose is to warm and humidify the air before it reaches the lungs. Because of the wide variation of human habitats from the polar cold and dry air to the equatorial hot and humid weather, one would expect the nose to accommodate to these climate extremes accordingly thru evolutionary pressures.

In essence, logically one would expect the nose to change shape to enhance time that air is in contact with the warm and moist nasal interior in cold and dry climates compared to the opposite environmental extreme.

German scientists evaluated this hypothesis thru 3D modeling of 100 skulls to analyze the shape of the bony nasal cavity of 10 modern human groups living in five different climates and found that the bony nasal cavity appears mostly associated with temperature effects and the nasopharynx with humidity.

Humans living in cold, dry climates tended to have nasal cavities relatively high and long with an abrupt narrowing in the upper nasal cavity than those living in hot, humid climates. Such characteristics enhance contact between the air and the nasal mucosal tissue that helps to warm and humidify that air.

What does such a nose look from the outside? A narrow, longer internal nasal cavity is generally linked to a relatively narrower and more projected nose.

Read a magazine article about this research.

Reference:
Climate-related variation of the human nasal cavity. American Journal of Physical Anthropology. Volume 145, Issue 4, pages 599–614, August 2011