Individuals of many species, including humans, differ consistently in the way they behave. These consistent behavioral differences among individuals are collectively known as animal personality (Gosling 2001), behavioral syndromes (Sih et al. 2004a), behavioral strategies (Benus et al. 1990), or behavioral profiles (Rodgers et al. 1997). Each of these terms, to some extent, describe an emergent phenomenon of the total biases in behavioral reactions an individual expresses compared to other individuals within the same population or species. In other words, animal personality, in addition to referring to consistent differences between individuals, also refers to correlated behaviors. These correlations (usually defined at the level of populations of individuals) can occur through time (an individual that is bold at one time is also bold at another), across different functional contexts (an individual that is bold toward a predator is also aggressive toward conspecifics), or some combination of time and context (juvenile exploratory behavior is related to adult sociability). Although there is some debate on terminology (e.g., Réale et al. 2007; Gosling 2008), we use the term “animal personality” throughout this chapter.