As a spanking new grad student, I showed up for my first class, “Primate Ecology” uber-excited and ready to learn all I could about the fascinating world of primates. Pen in hand, I was armed and ready to furiously copy down pages of notes as I had done before in my undergrad courses. But then, without so much as a greeting to the class, my adviser waltzed into the room, dumped a box of jaw fragments on the table, and said “You have the remainder of the class to detail all you can about these primates. You may leave your papers on the podium, and I will see you tomorrow.” Several of my peers quickly jumped up, eager for the challenge, while I seriously considered high-tailing it out the door. I had never studied human anatomy, let alone primate dentition! What was I doing here, and how in the world was I to come up with anything to write?

I decided to stay and muddle my way through that first day. I wrote about variables such as how large or small I thought the primate was, and whether any of the teeth were obviously missing. Little did I know that so much more can be learned from primate jaw fragments or that the next two years of primate classes would generally involve some form of huddling over a dissecting microscope, carefully analyzing details of tiny little primate teeth. And if I was taught anything during my time volunteering as a primate dentist’s apprentice, I definitely learned how to tell what kind of “oogivore” you are.

• Frugivore: predominantly eats fruit: back teeth tend to be broad with round cusps, two incisors in the front are wide and somewhat spoon-shaped
• Folivore: munches on leaves and vegetables: back teeth tend to be large with high cusps to shred tough leaf material, two front teeth are narrow
• Graminivore: likes seeds/nuts and grains: back teeth are tall and strong, incisors are variable
• Gummivore: scrapes up gums, saps, and other tree fluids: all teeth are small and somewhat pointy, front teeth stick out straight for scraping bark
• Carnivore: devours meat: back teeth are adapted for shredding meat (not grinding), canines and incisors are long and sharp
• Insectivore: chomps insects: all teeth are small and very sharp for crushing exoskeletons of insects
• Omnivore: sophisticated palate and likes to eat a little bit of everything: teeth are variable in size and appearance

And what good are these little parcels of dentary knowledge? Put quite simply, animal teeth reflect the type of foods that predominates the diet. In turn, the type of diet tells us a lot about where the individual might have been living and even how his social system may have been set up.

Though the dietary descriptions based on tooth shape make sense, perhaps even seeming self-explanatory, it has taken extensive research to construct these types of generalizations. And just why are the teeth of primates and other animals so well-studied? The answer is rooted (no pun intended) in paleontology, more specifically in fossil preservation. Some of the most consistently well-preserved mammal fossils are the lower jawbones (mandibles), which are very hard bones.

Have you ever read the Biblical story of how Samson puts the mandible of a donkey to use? Judges 15:16 reads, “Then Samson said, “With the jawbone of a donkey, I’ve piled them in heaps! With the jawbone of a donkey, I’ve killed a thousand men!”

Mandibles are thick, strong bones, and they are often all that remains of a fossilized organism after the more delicate bones of the body are destroyed over time. Thousands of scientists have spent countless hours studying the intricacies of teeth and jaw bones, using the teeth of living specimens to make predictions about fossilized organisms. In addition to dietary type, other variables, such as species identification, age, health, and body size, can be garnered from looking at dentition. Just a couple of teeth embedded in a mandible are enough to tell a scientist that she is looking at the remains of a juvenile spider monkey approximately five pounds in weight that liked to feed predominantly on fruit. Not too shabby!

So, get out a mirror and check out your chompers. What type of oogivore are you?

This entry was posted on Monday, February 22nd, 2010 at 11:25 am and is filed under Primate Anatomy.