Animals vary in the extent to which they are aware
of themselves (DeGrazia 1996) and of their interactions
with their environment, including their ability to experience pleasurable states such as happiness and aversive states such as pain, fear and grief. This capacity
may be referred to as their degree of sentience. A sentient being is one that has some ability to evaluate the
actions of others in relation to itself and third parties, to
remember some of its own actions and their consequences, to assess risk, to have some feelings, and to
have some degree of awareness (Broom 2006).