Animals may display a variety of responses to a stressor, including behavioural and physiological responses (Hofer & East, 1998). These symptoms in cetaceans are typically disguised, and stressors, or even diseases, often are not detected until they are advanced. In many cases, a behavioural response may be the first indicator and a clue to underlying causes, and there is good reason to believe that behavioural observations can be used to assess animal well-being (Carlstead et al., 1993; Baker & Aureli, 1997; Waples & Gales, 2002; Owen et al., 2004).