A new study has concluded there to be a physiological purpose to male humans possessing larger noses than females. This variation in nose size is posited to hinge upon differences in muscle mass, and the attendant oxygen demand, observed between genders.
The study was performed by a research group working at the University of Iowa and funded by the Department of Orthodontics, the results of which were published in the latest issue of the American Journal of Physical Anthropology.
The research group monitored the change in nose size and growth of a sample of 38 individuals, all of whom were of European descent. Participants enrolled in the Iowa Facial Growth Study from three years of age and were consistently studied over the years, until they reached their mid-twenties. Internal and external measurements were periodically taken and assessments were performed to establish whether there were significant differences in “nasal/body size scaling relationships,” between males and females.
Researchers used around 300 data points from X-rays, alongside a number of additional physical examinations, to draw their conclusions.
Nose Size Difference Becomes More Pronounced During Puberty
The team found that men’s noses are, on average, around 10 percent larger than female noses in populations of European descent. It has been suggested that this disparity is based upon the different physiological builds and metabolic demands, evident between male and female individuals. Generally speaking, males tend to have a greater proportion of lean muscle mass, which necessitates delivery of more oxygen for the purposes of tissue growth and repair. A larger nose facilitates inhalation of larger volumes of oxygen; it is then delivered to the lungs and subsequently transported in the bloodstream to supply muscles with sufficient oxygen for aerobic respiration.
Intriguingly, it appears that nose size differences start to become apparent around the age of 11, close to the time when puberty strikes. During puberty, males develop more lean muscle mass, whereas females start to lay down greater amounts of fat tissue, especially around the breasts, buttocks, hips and thighs.
Assistant Professor at the University of Iowa College of Dentistry Nathan Holton, who was lead author of the new research study, talked about the disproportionate changes in nasal size that emerges between genders. He claims the change is entirely consistent with the rapidly evolving energetic variables witnessed during development, including oxygen consumption, metabolic rate and daily energy expenditure.
From age 11 onwards, the team found that the size difference in noses between males and females became increasingly pronounced. Even in situations where the body sizes of individuals of different genders was the same, males were always found to have larger noses; Holton explains this to be caused by the afore-mentioned divergence in body composition:
“… 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.”
Ancestral Differences in Nasal Size
The researchers also seek to apply their deductions to explain the evolutionary divergence in the nose sizes of modern man compared to those of our ancestors, such as the
Neanderthals. For the same reason that males of today have larger noses than females, it is theorized that our distant lineages had larger noses because they had more lean muscle mass. Holton elaborated on this point, during a recent press release:
“So, in humans, the nose can become small, because our bodies have smaller oxygen requirements than we see in archaic humans… This all tells us physiologically how modern humans have changed from their ancestors.”
Holton also points to the fact that we have smaller rib cages and lung capacity, relative to our ancestral counterparts, strengthening the notion that we do not require the same volume of oxygen to support growth and repair processes.
Ultimately, in drawing their conclusions, Holton and colleagues highlight that the nose is not merely some form of facial adornment, but remains an invaluable extension of our lungs. In this sense, Holton believes that the nose could be considered “… more closely tied with non-cranial aspects of anatomy.”
The group also explain the limitations of their study, having only investigated people of European descent. However, they believe their findings should remain applicable to other populations, since male and female physiology patterns are consistent across cultures and races. Further, with such a small sample sized employed throughout the study, the researchers admit that additional investigation is required.
By James Fenner