Vertebrate herbivores in marine and terrestrial environments: A nutritional ecology perspective

The study of digestive physiology provides a framework for analyzing food resources, feeding patterns, and evolutionary trends in vertebrate herbivores. Most of the research in this field, nutritional ecology, has been focused on terrestrial herbivores, especially mammals. By integrating physiological, demographic, and evolutionary approaches, the study of terrestrial herbivores has generated several important hypotheses, notably on factors determining body mass. Marine vertebrate herbivores are abundant and locally diverse, but with the exception of reptiles and mammals, we lack information on digestive physiology and processing of plant foods, the key element in terrestrial studies. This review provides a foundation for a nutritional ecology of marine vertebrate herbivores, especially teleost fish, by summarizing the available information on their digestive physiology and identifying research priorities in the field.