Duck-billed dino could slice and dice

Duck-billed dinosaurs were the Cuisinarts of the Late Cretaceous period. They pulverized tough, gritty plants such as conifer trees using hundreds of rough, interlocking teeth that sported an array of filelike crests and basins. Now, scientists have figured out how the herbivores developed such complex chompers: The animals’ teeth contained six distinct types of tissue that wore to differing degrees, creating distinctive peaks and valleys.