Males and females begin to show differences in nose size at around age 11, generally, when puberty starts, says study. Researchers at University of Iowa believe that the size difference comes from the sexes' different builds and energy demands: Males in general have more lean muscle mass, which requires more oxygen for muscle tissue growth and maintenance. Larger noses mean more oxygen can be breathed in and transported in the blood to supply the muscle.
Physiologically speaking, males begin to grow more lean muscle mass from that time, while females grow more fat mass.
"This relationship has been discussed in the literature, but this is the first study to examine how the size of the nose relates to body size in males and females in a longitudinal study," lead author Nathan Holton, assistant professor in the UI College of Dentistry, said.
"We have shown that as body size increases in males and females during growth, males exhibit a disproportionate increase in nasal size. This follows the same pattern as energetic variables such as oxygenate consumption, basal metabolic rate and daily energy requirements during growth," Holton added.
It also explains why our noses are smaller than those of our ancestors, such as the Neanderthals. The reason, the researchers believe, is because our distant lineages had more muscle mass, and so needed larger noses to maintain that muscle. Modern humans have less lean muscle mass, meaning we can get away with smaller noses.
The researchers found that boys and girls have the same nose size, generally speaking, from birth until puberty percolated, around age 11. From that point onward, the size difference grew more pronounced, the measurements showed.
The study is published in the American Journal of Physical Anthropology.