What Teeth Tell Us
You can learn a surprising amount of information from an animal’s teeth, and dinosaurs are no different. As we’ve already seen, Gideon Mantell and William Buckland described Iguanodon (which you’ll remember means “iguana tooth”) and Megalosaurus based largely on their teeth. Chompers are tough and are among the most likely of an animal’s skeletal elements to be fossilized.
Teeth can provide insight into a dinosaur’s diet. Obviously, the pointy ones are for meat. But differently shaped teeth can provide more subtle clues. Allosaurus had thinner, more sword-like teeth than Tyrannosaurus with its round, railroad spikes. Allosaurus teeth cut meat from bone, while T. rex crushed bone. Still more different, Spinosaurus carried conical teeth in its jaws–the same kind of teeth employed in today’s fish-eating animals.
The same thinking can be applied to other dinosaurs. The pesky business of whether Apatosaurus and Brontosaurus are two different species is partially based on their peg-like teeth. After recent skeletal studies indicated that skeletal elements differed between the two, special care was taken to examine the teeth. Researchers have indicated that Apatosaurus teeth are one-third skinner than those of Brontosaurus, and look a bit different, too. Even though Apatosaurus is larger, it was dining on more delicate vegetation.
Diet and teeth go hand in hand, but scientists can use teeth to solve even more elusive riddles. Several years ago, a group of researchers at Caltech used the physical chemistry of tooth enamel isotopes to determine the temperature of the body that produced the teeth. They found that dinosaurs were metabolically warmer than modern “cold-blooded” reptiles, but not quite as “hot-blooded” as modern birds. See a more detailed explanation of how they determined this:
Unlike us, dinosaurs continually regrew their teeth throughout their lives. Some had batteries of hundreds of vegetation shears, while others were content with just a few small nippers. But whatever their habits, dinosaurs and their teeth continue to gnaw at our imaginations.