Many of us derive inspiration from watching natural history documentaries and their astounding catalogue of wild animal behaviours. In this course, we will explore how scientists study animal behaviour, and in particular how behaviour is shaped by the evolutionary forces of natural and sexual selection. Topics include resource acquisition; avoiding enemies; mate choice and sexual conflict; cues, signals and communication; parental care and social behaviour; and the role of genes, hormones and learning in regulating behavioural diversity. We draw on examples from across the animal kingdom to illustrate the complex mechanisms underlying adaptations, and complement these with natural history videos that highlight key concepts. We evaluate the scientific rigour of studies used to test theory, and highlight the often ingenious methods adopted by researchers to understand animal behaviour.