All animals must eat. In this respect, at least, we are no different from other heterotrophs – we take in solar energy indirectly, by consuming other organisms. This way of life has characterized multicellular animals since their origins more than five million years ago. But heterotrophy is a broadly defined ecological category that gives no hint of the diversity of feeding methods and adaptations found among animals. That these adaptations – morphological, developmental, or behavioral – vary in regular ways between species, genera, families, and even higher taxonomic groups is today a noncontroversial assumption among evolutionary biologists. Still fiercely debated, however, is the hereditary basis of feeding strategies: Which behaviors and preferences are more or less fixed by genetic inheritance and which are free to vary in response to the individual's environment?