AbstractThe primary concern of all animals is to find and ingest food to cover their dietary needs. Evolutionary pressures have constructed efficient, rapid and adjustable series of movements of morphological structures that permit the gain of nutrients and energy necessary for fitness of the animals. In vertebrates, the diversification of this activity underlying the success of nutritive processes has played a key role in animal ecological diversity, although the feeding system represents only modifications of the same basic set of homologous skeletal structures either directly connected by articulations or by contact with soft tissues. Therefore, feeding efficiency in the two main lineages of domestic animals, birds and mammals, results from the strong relationship between structures, performances, behaviour and fitness. This chapter discusses the evolution of the morphology and anatomy of domestic animals in their adaptation to their feeding behaviour and domestication. The chapter provides a synthesis of several aspects of feeding, which is one of the primary concerns of all animals by collecting together various approaches of the complex function of feeding in birds and mammals and the internal and external factors regulating this function.