This comprehensive textbook discusses the study of animal behaviour, its origins in classical ethology and its current status. Factors determining the course and eventual outcome of the development of behaviour are investigated. The adaptive significance of behavioural traits such as habitat selection, foraging patterns, group living and territorial and mating behaviour is examined. In the analysis of behavioural change, consideration is given to the theory and application of motivational models and the interface between physiological and behavioural research. Topics discussed include the evolution of co-operation and altruism, the strengths and weaknesses of the sociobiological approach, behavioural genetics, practical applications of ethology and the general influence of animal behaviour on the course of evolution.