Our ever-shrinking chops.

Accordingly, if a large jawbone is found during a dig, it will normally come from a person with a larger frame. It would be false, however, to assume that the person is male. “The pelvic bone is the only bone whose dimensions are a somewhat reliable indicator of biological sex,” explains Werner Vach, the IPAS research associate in charge of statistical analysis. According to Vach, this study was the first to explore the possible connection between tooth and jaw size and sex in such a systematic approach.

Nevertheless, some sex-specific differences were discovered between the impressions taken from the male and female participants. The jawbone showed a greater correlation between measurements and sex. “It influences facial proportions, and sex effects play a larger role — not just in terms of biological sex, but also social sex. We classify a prominent chin as male, while a narrower chin appears female,” says Vach. In forensic analyses, the jaw could therefore be a more precise indicator of biological sex than the teeth. Only the canine teeth show more significant differences: They were around 30 percent larger in the men, while the rest of the teeth differed only by around 10 percent.

Form follows function.

“Evolution follows the principle of form follows function. Meat-eating creatures developed a different set of teeth to plant-eaters. The same goes for the gastrointestinal tract,” explains Kurt W. Alt, who specializes in dental anthropology and analyzes teeth to draw conclusions about modern and historical populations.

The human diet has changed significantly over time. The discovery of fire around two million years ago proved to be a turning point: Food could be heated, and the cooking process made it softer. Around 14,000 years ago, sedentism also changed the food that humans could access. They stopped living mainly off hunted animals, berries, mushrooms and roots, and began to cultivate crops and keep livestock.

Density stress in the jaw.

These major cultural changes have influenced the evolution of the teeth and jaw, which have become smaller over time — although not simultaneously. “There is limited overlap between the development of the jaw and teeth,” says Alt. This also leads to difficulties. A contemporary adult has between 28 and 32 teeth, depending on whether they still have (or never even developed) their wisdom teeth. For 70 to 80 percent of people, they have either never had their third molars or have had them removed for health reasons. “Because the jaw has evolved to be smaller, there often isn’t enough space for all the teeth. Accordingly, the oral cavity has also shrunk, which today contributes to sleep apnea,” he says.

Our teeth are yet to adapt to modern, mostly soft, food. The teeth are formed and sized to grind up much harder consistencies than are often required. “If we follow a diet filled with convenience products, we chew a lot less than our ancestors needed to. We could get by with fewer teeth,” says Alt.

He therefore expects that our teeth and jaws will continue to shrink in the future. In fact, we may not even develop some of the teeth we have today — as we’re already seeing with wisdom teeth. This trend has been observed for decades. Alt talks of a “microevolution in the background.” Statistician Vach waxes philosophical: “Changes like these aren’t bad in themselves. Vampire-like fangs don’t make sense if we don’t need them.”