This textbook for advanced graduate and postgraduate veterinary students introduces animal behaviour, offering insights into its origins, cognitive aspects, communication, environmental influences, biological mechanisms, complex behaviours, adaptive strategies, and practical applications. The initial chapters present fundamental principles underpinning animal behavior, elucidating the roles of evolution, genetics, and ecology. Subsequent chapters introduce the role of natural selection, habitat selection, foraging strategies, and pheromones, alongside exploring conflicts, predator-prey dynamics, and the impact of domestication on behaviour. It unravels the mysteries of animal defences, altruism, social dominance, territoriality, and the finely tuned art of food and habitat selection. Additionally, it covers the biological mechanisms governing behaviour, unearthing the roles played by neuroendocrinology, biological clocks, and genetics. Towards the end, the textbook examines the practical relevance of behavioural insights in veterinary science.