Among his academic peers, Daniel Lieberman, 47, is known as a “hoof and mouth” man.

That’s because Dr. Lieberman, an evolutionary biology professor at Harvard, spends his time studying how the human head and foot have evolved over the millenniums. In January, Harvard University Press published his treatise, “The Evolution of the Human Head.”

We spoke in a Cambridge hotel room for three hours last winter and then again on the telephone in June. An edited and condensed version of the two conversations follows.

Q. Why heads?

A. Our heads are what make our species interesting. If you were to meet a Neanderthal or a Homo erectus, you’d see that they are the same as us — except from the neck up. We’re different in our noses, ears, teeth, how we swallow and chew. When you think about what makes us human, it’s our big brains, complex thought and language. We speak with our heads, breathe and smell with our heads. So understanding how we got these heads is vital for knowing who we are and what we are doing on this planet.

Q. Are there any practical benefits to your research?

A. There are. A majority of the undergraduates who register for my evolutionary anatomy and physiology class here at Harvard are pre-medical students. Learning this will help them become better doctors. Many of the conditions they’ll be treating are rooted in the mismatch between the world we live in today and the Paleolithic bodies we’ve inherited.