The book attempts to provide a reasonably suitable account of animal behaviour for undergraduate as well as postgraduate students. Although behaviour of animals has fascinated people for a long, behavioural biology has been incorporated in the syllabi very recently. The study of behaviour received its important boost from the work of Charles Darwin who used the term ‘instinct’, to refer to the natural behaviour of animals. In the 1930s, a comprehensive theory of animal behaviour emerged through the work of Konrad Lorenz and, later of Niko Tinbergen. Biological study of behaviour, in fact came of age as a science when Lorenz, Tinbergen and Karl von Frisch received the Nobel Prize for their contribution to science. Observing and describing exactly what animals do is fascinating and scientific analysis of their behaviour is significant for several reasons. Each species tends to have an array of stereotyped behaviours, some of which are shared with related species, but others are unique. Ecology, natural selection, macroevolution, microevolution, and gene constitute the foundation of animal behaviour. Various animal groups exhibit diverse strategies for their survival and reproduction which are discussed in this book. The book is primarily intended for the students of B.Sc./M.Sc. (Zoology/Life Science) for their courses. It would be useful for the researchers in the field of animal behaviour, and conservation biologists. It would also attract students who are pursuing courses in Sociology and Anthropology.