Why do they do that? is the question theories of psychopathy should answer. Current theories of psychopathy fail to answer this question because they focus on affective and inhibitory deficits rather than on motivation. Antisocial behavior is appetitive and therefore can only be explained with a motivational theory. This chapter presents a motivational theory of psychopathy that draws on the ethological framework. The chapter answers all four questions of ethology as applied to psychopathy.