‘What teeth do: food and feeding’ explains that to appreciate what teeth do, we first need to understand what vertebrates need from them. Different animals make different choices to meet their needs for energy and raw materials. Animals may choose foods for their chemical nutrient properties, but teeth evolve with physical properties in mind. To understand how teeth work, we need to know more than how dental form relates to food fracture properties. We need to know how animals use their teeth — how they get food into the mouth, and how they prepare it for the gut. But relationships between tooth form and diet are also complicated by wear. Teeth change shape over time.