"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."
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 clos
|Contact: Richard Lewis|
University of Iowa