Tooth by Tooth by Sara Levine
Before reading this book, I expected one of two things: either a comparison of tooth types or some examples of animals of with unusual dentition. The reality is a nice blend of these ideas. Levine takes us through the purpose of each type of tooth and what various combinations of them mean in regards to what the animals eat. Most tooth grouping get multiple examples (not just beavers with large incisors, but mice, hamsters, and more). A nice introduction for kids interested in animals.
And as a side note, can I just say how much it entertains me that the illustrator goes by the name T.S. Spookytooth.