A new research suggests that guys have bigger noses than girls because they need more oxygen for their more muscular body.

According to Nathan Holton, a biological anthropologist at the University of Iowa and the lead author of the study, the size of the nose is relatively related to the amount of oxygen a human body requires.

To confirm speculations, researchers studied the development of noses. The study group included 20 men and 18 women with European descent. Their analysis relied on roughly 300 data points including X-rays and other physical tests taken from the Iowa Facial Growth Study since the participants were just three years old.

The researchers have discovered that both men and women participants have the same nose sizes when they were still young. However, during the adolescent years, nose sizes of men start to increase and it concurs with how men consume more oxygen and energy compared to women upon puberty.

In general, nose sizes of men are roughly 10 percent higher than women's on the average.

Holton said, "As body size increases in males and females during growth, males exhibit a disproportionate increase in nasal size." He added, "This follows the same pattern as energetic variables such as oxygen consumption."

That might also explain why Neanderthals have bigger noses than the modern humans.

Based on the comparison between skeletons of Neanderthals and modern human, the former have bigger body masses, so they have bigger noses making them able to inhale huge amounts of oxygen needed to supply their whole body.

According to earlier studies, aside from bigger noses, men also have bigger nasal cavities and airways. Furthermore, during nasal breathing, men consume more oxygen than women. However, it still doesn't verify that the sizes of the nose depends on the person's oxygen requirement – perchance, the size of the nose might be associated with other body functions.

Holton told LiveScience, "The large noses in groups like Neanderthals may be constrained to be large because they had greater mass and therefore required more oxygen. With the reduction in body mass seen in modern humans, these constraints would be lifted and noses would reduce in size."

This study was published on the online journal American Journal of Physical Anthropology.