What sets Homo sapiens apart from other animals? Among other things, our
chins do. That piece of bone sticking out from your jaw is somewhat of a mystery - one that's inspired a diversity of wild theories to explain its purpose, according to a paper published this month in
Evolutionary Anthropology.
The author of the paper dismisses a number of these explanations, such as the possibility that the chin serves as a sexual signal (such traits usually only appear in one sex - like the mane of a male lion). Another proposal is that the chin acts to protect your throat - an idea the paper's author also shoots down, because for this to be a substantial advantage, humans would have to be constantly punching each other in the face.
So the mystery remains, why did chins beat no-chins. It could be as uninteresting as chins were more aesthetically pleasing (and hence, more likely to attract a breeding partner). While evolutionary success often correlates with some attribute that better enables the organism to survive in its environment, the real decisive factor is reproductive success.
