If These Teeth Could Talk

3 minutes

(male narrator) It's as if these teeth can talk.

(Peter Ungar) These are replicas of the most important fossil skulls in the human fossil record.

(narrator) Anthropologist Peter Ungar uses casts of jaws, teeth, and skulls to study diets of ancient animals and how they have evolved over time. Here's a gorilla skull. The teeth on this thing are huge. They're also very cresty, which makes them well-suited for grinding up and shearing and slicing leaves and other tough vegetation.

(narrator) With support from the National Science Foundation, Ungar's team at the University of Arkansas study microscopic scratches on thousands of teeth from primates to dinosaurs. Eating hard or tough things could be hard work.

(narrator) For years, scientists believed that because early hominids had huge teeth and jaws, that meant their diets were derived of tough stuff like seeds and nuts. But using new tools like these, Ungar can see minute abrasions.

(Ungar) You can see the wispy scratches across the surface.

(narrator) Our ancestors were like us. They'd rather eat something soft and tasty than something hard to crack and chew. Big teeth and jaws only suggest what they could eat when food was scarce, not necessarily what they did eat when tempting fruits were plentiful. Looking at the microscopic wear on those teeth, it's quite rare to see the heavy pitting one expects from a hard-object feeder. More often, there are light, wispy scratches, which is what we see in soft-fruit feeders.

(narrator) Observe the wear and tear of this human ancestor's teeth. Now look at this monkey's teeth, known to eat hard, brittle foods.

(Ungar) Instead of two or three microns in depth, this is eight.

(narrator) Ungar receives dental casts of fossils from museums worldwide. Take our fossil, and just squirt it with this impression material.

(narrator) Casts are also made from live subjects. Ungar says more information about ancient animal diets will help shape understanding of behavior, migration patterns, and evolution.

(Ungar) They are like footprints-- records of something the animal rejected. It's cool to see that.

(narrator) A new view of the past you can sink your teeth into. For Science Nation, I'm Miles O'Brien.


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With funding from the National Science Foundation, Peter Ungar is revealing more details about the lives of human ancestors, and he’s doing it through dentistry. The University of Arkansas anthropologist uses high tech dental scans to find out more about the diets of hominids, a technique that sometimes leads to new and very different conclusions. While anthropologists traditionally determine the diets of our ancestors by examining the size and shape of teeth and jaws, Ungar's powerful microscopes paint a more detailed picture by looking at wear patterns on teeth.

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