Understanding behavioural diversity is important for commercial production, animal behaviour and welfare. One interpretation of individual differences in behaviour is that these represent different strategies for coping with a changing environment. For example, Hessing et al. (1994) categorized pigs as active/resistant or passive/non-resistant, based on each pig’s reaction to restraint. However, these conclusions have been criticized. For example, Jensen et al. (1995) argued that for two such categories to exist, there must be a bimodal distribution of the scores from a population, which Hessing et al. (1994) failed to demonstrate. Determining individual behavioural characteristics and any relationship they may have with performance has been the focus of recent research. The objective of this experiment was to determine the primary characteristics that distinguish individual pigs.