This book is an attempt to make the students of under graduate level understands the current state of animal body at the level of its functional features. Emphasis in this book is mainly on the functions of its component organs and organ systems under its natural environment. Phenomena at subcellular to tissue levels are discussed to provide perspective at organs to whole body level.

The subject of physiology being exhaustive, the author has treated only those topics in each system which has been included in the course outlines of Animal Physiology designed by the Indian Universities for their under-graduate and graduate classes in the subject of Zoology.

The phenomena of life processes cannot be explained without going into the details of biochemical events that occur at molecular level; the first three chapters of this book are devoted to the structure, chemical properties and biological significance of macromolecules of physiological importance to prepare the student to understand the part of the material which follows in the subsequent 12 chapters. Efforts have been made to produce a text that will be useful, informative and stimulating for the students opting for Animal Physiology as one of the core subject in animal sciences and other interested readers.