What is animal happiness?

Today we see a growing concern for the quality of life of non-human animals and an accompanying call for viable means of assessing how well animals thrive. Past research focused on minimising negatives such as stress, while more recent endeavours strive to promote positives such as happiness. But what is animal happiness? Although often mentioned, this term is lacking a clear definition. With recent advances in the study of animal emotion, the current interest into positive as well as negative experiences and the call for captive and domesticated animals to have a good life, the time is ripe to examine the concept of animal happiness. We draw from human and animal literature to delineate a concept of animal happiness and propose how this could be assessed. We argue that animal happiness depends on how an individual feels generally, that is, typical level of affect