Humans Are One of Two Chinned-Species

It is well known that humans have unique fingerprints. But did you know that our chins also set us apart? In fact, the only other species with a chin is the elephant. So why do we have a chin? And how did it get there in the first place?

Several early theories existed regarding the origin of the human chin. The two most popular notions were: chins help us speak and chins distribute the stress of chewing. Early scientists also believed that the chin existed to attract mates. However, these theories could not be definitively proved.

Anthropologist T.T. Waterman was the first to contradict these hypotheses in 1916. He believes that the chin was a result of our ancestors’ shrinking faces. Many scientists support Waterman’s theory today.

At the University of Florida, evolutionary anthropologist James Pampush recently studied the chin and its functions. Pampush considered more than 100 primate species in his study, including chimps, lemurs, and humans. After completing CAT scans and measuring these species’ jaws, Pampush discovered that jaw angles have changed rapidly for humans overtime. This is not true for other species, thus indicating that natural selection must have been at play in the evolution of human chins.

According to paleoanthropologist Robert Franciscus, the shrinking of the human chin relates to early humans displaying less aggression and having less testosterone. Fossils from our ancestors show that lower hormone levels resulted in smaller faces, which ultimately led to a more cooperative, socially-tolerant human species.

If humans today still had the high testosterone levels that our ancestors did, we likely would not be where we are now. We wouldn’t be working and living cooperatively with each other. So, the next time you look in the mirror, think about this; the protrusion you have under your mouth is not just a landing pad for a beard, it’s also a sign of evolution.

[Source: Smithsonian Magazine]