(Photo: Corpse Reviver)
Humans alone have chins. Why? Scientists have speculated over that question for decades. What evolutionary advantage does the chin offer? Dr. Robert G. Franciscus and his colleagues at the University of Iowa suggest an explanation: the chin is simply the result of the reshaping of the rest of the human skull:
Using advanced facial and cranial biomechanical analyses with nearly 40 people whose measurements were plotted from toddlers to adults, the UI team concludes mechanical forces, including chewing, appear incapable of producing the resistance needed for new bone to be created in the lower mandible, or jaw area. Rather, they write in a paper published online in the Journal of Anatomy, it appears the chin's emergence in modern humans arose from simple geometry: As our faces became smaller in our evolution from archaic humans to today -- in fact, our faces are roughly 15 percent shorter than Neanderthals' -- the chin became a bony prominence, the adapted, pointy emblem at the bottom of our face.
Dr. Franciscus does not, however, provide an explanation for the development of multiple chins.
-via VA Viper