Animal psychology and animal behaviour are interesting topics in their own right, but when studied on an island such as Lundy, even more so. In this chapter the both are introduced. The accompanying discipline of Ethology (the study of animal behaviour) is also examined, and its emergence in the early 1930s and subsequent development are described. Examples of the kinds of studies carried out by ethologists are given. These include pure ethological studies, such as those involving the comparison of the behaviour of 'kept' animals with their wild counterparts and the monitoring the occurrence of specific behaviours such as abnormal behaviours (e.g. stereotypes and vices) and applied ethological studies, such as those involving manipulation of the animals, often making use of control and experimental groups of animals. The importance of applied ethological work with regard to animal welfare is also noted. The animals on Lundy have been the subjects of many behaviour studies in the past, both pure, and more recently, applied. Some of the findings of work on the Lundy grey seals, rats, feral goats, sika deer, and also domestic species, such as the ponies, sheep and cattle are described.