How I Came to Write Tooth by Tooth: Comparing Tusks, Fangs, and Chompers

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“I knew from teaching at Wheelock that students loved to puzzle out questions about variation, and I thought children would, too.”


Today’s post comes from Wheelock professor and author Sara Levine, who has recently released Tooth by Tooth: Comparing Tusks, Fangs, and Chompers. She is also the author of Bone by Bone: Comparing Animal Skeletons. She’ll be giving a reading of the book on Saturday, August 6th at 11:00am, at Newtonville Books in Newtonville, MA.

at readingWhen I started teaching at Wheelock a decade ago, I was pleased to discover a skeleton in the closet. Actually, there were many, both human and animal. I found a fully articulated rattlesnake skeleton, each fragile rib carefully glued into its adjoining vertebra; a mounted bat skeleton; and a variety of animal skulls. My students and I enjoyed the challenge of identifying them—a boar, a cat, a horse, a dolphin. One mystery skull took a long time to figure out—it was broad, with massive canine teeth, suggestive of a cougar or bear. But the size measurements didn’t fit any of our field guide descriptions of large, carnivorous animals. Eventually, it occurred to me that it might be a marine mammal, as the field guides we were using covered only land mammals. It was: a seal.

I began to use these skulls and later additions to the collection (all plastic, as I like knowing no animals were harmed), to teach a hands-on lab on comparative anatomy in my Introduction to Plants and Animal course. I want students to see that mammals have basically the same types of teeth—incisors (you have eight total in the front of your mouth, four on the top and four on the bottom), canines (the pointy ones after the incisors—four total, two top and two bottom) and molars (all the rest, behind the canine teeth).

Human teeth are all around the same height because of our varied, omnivorous diet. But other mammals’ teeth are more interesting, and more specialized for specific functions. If a mammal eats predominantly meat, it will have long canine teeth for killing and tearing the meat. If a mammal eats predominantly plants, it will either have large incisor teeth, for cracking open nuts or taking bark off a tree, or large molar teeth, for grinding up grass or leaves. These differences in tooth structure later inform our class discussion of mammal taxonomy—how mammals are categorized.

ToothbyTooth_cover high resolutionIn the lab, once students learn to differentiate types of teeth, they can identify them on individual skulls and use this to determine the animals’ feeding patterns. And, then, for fun, they can guess what kind of animals the skulls come from. Some students, by the way, are uncannily good at this for reasons I have yet to figure out. But practically everyone is terrible at identifying a pig skull, probably because most students have been exposed only to cartoon-shaped pigs, rather than real-life ones.

The idea of making this tooth and skull lab into a book for children occurred to me after the publication of my first book, Bone by Bone: Comparing Animal Skeletons. The premise was similar – learning about animals by comparing body structures. I like my books to be interactive, and in this one I could ask questions to get children to think about how our teeth are both the same and different from those of other mammals.

I knew from teaching at Wheelock that students loved to puzzle out questions about variation, and I thought children would, too. I had some good challenges about teeth: What kind of animal has top canine teeth that extend all the way down to its feet? Care to guess? The answer is a walrus. Or, what about an animal with incisors which extend out of its mouth and curl up towards the sky? Guess? An elephant.

Writing this tooth book didn’t come as easily as the bone book, though, because at first I couldn’t think of enough examples. This led me to do research – and to the discovery of more wacky variations on tooth morphology—enough to fill a picture book. For example, what kind of animal would you be if one of your top incisors pierced through the skin of your upper lip and continued to growing until it was longer than the whole rest of your body? Want to know? I hope so. Maybe you’ll read the book to find out.

Brenda's boys reading both books
Two avid fans of Levine’s work.