Male noses grow disproportionately larger
than female noses beginning at puberty, a University of Iowa study has found.
The reason: Males need to breathe in more oxygen to feed muscle mass than
Human noses come in all shapes and sizes.
But one feature seems to hold true: men’s noses are bigger than women’s.
More lean muscle mass
A new study from the University of Iowa
concludes that men’s noses are about 10% larger than female noses, on average,
in populations of European descent. The size difference, the researchers
believe, 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.
The researchers also note that males and
females begin to show differences in nose size at around age 11, generally,
when puberty starts. Physiologically speaking, males begin to grow more lean
muscle mass from that time, while females grow more fat mass. Prior research
has shown that, during puberty, approximately 95% of body weight gain in males
comes from fat-free mass, compared to 85% in females.
“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,” says Nathan
Holton, assistant professor in the UI College of Dentistry and lead author of
the paper, published in the American Journal of Physical Anthropology. “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.”
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.
“So, in humans, the nose can become small,
because our bodies have smaller oxygen requirements than we see in archaic
humans,” Holton says, noting also that the rib cages and lungs are smaller in
modern humans, reinforcing the idea that we don’t need as much oxygen to feed
our frames as our ancestors. “This all tells us physiologically how modern
humans have changed from their ancestors.”
Holton and his team tracked nose size and
growth of 38 individuals of European descent enrolled in the Iowa Facial Growth
Study from three years of age until the mid-twenties, taking external and
internal measurements at regular intervals for each individual. 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.
“Even if the body size is the same,” Holton
says, “males have larger noses, because more of the body is made up of that
expensive tissue. And, it’s at puberty that these differences really take off.”
Across cultures and races
Holton says the findings should hold true
for other populations, as differences in male and female physiology cut across
cultures and races, although further studies would need to confirm that.
Prior research appears to support Holton’s
findings. In a 1999 study published in the European Journal of Nutrition,
researchers documented that males' energy needs doubles that of females
post-puberty, “indicating a disproportional increase in energy expenditure in
males during this developmental period,” Holton and his colleagues write.
Another interesting aspect of the research
is what it all means for how we think of the nose. It’s not just a centrally
located adornment on our face; it’s more a valuable extension of our lungs.
“So, in that sense, we can think of it as
being independent of the skull, and more closely tied with non-cranial aspects
of anatomy,” Holton says.
Picture: Nose from Shutterstock