Abstract
Welfare science has built its foundations on veterinary medicine and thus measures of health. Since bottlenose dolphins (Tursiops truncatus) tend to mask symptoms of poor health, management in captivity would benefit from advanced understanding on the links between health and behavioural parameters, and few studies exist on the topic. In this study, four representative behavioural and health measures were chosen: health status (as qualified by veterinarians), percentage of daily food eaten, occurrences of new rake marks (proxy measure of social activity), and willingness to participate (WtP) in Positive Reinforcement Training sessions as qualitatively measured by their caretakers. These data were collected multiple times a day, every day over the course of a year from a multi-facility, large sample size (ndolphins = 51), allowing powerful analyses of the relationships between measures. First, it was found that dolphins with a higher WtP score also had a significantly better health status, ate a higher percentage of their daily food, and a lower occurrence of new rake marks. In addition, the WtP score was significantly lower up to 3 days before the weekly veterinary diagnosis of a decrease in health state; the percentage of daily food eaten and new rake mark measures did not show any significant change before such a diagnosis. These results suggest that WtP in training sessions is a potential behavioural measure of dolphin welfare, and an indicator of early changes in the dolphins’ health state. We therefore suggest measurement of WtP as a more practical and non-invasive tool to support veterinary care and general management. More work needs to be conducted to elucidate the influence of social behaviour on health, and to identify other potential welfare indicators, but this long-term study has shown that qualitative measures can be both practical and valid when assessing dolphin welfare.
Highlights
Welfare science, the objective measurement of animals’ affective states (Mason and Veasey, 2010; Hemsworth et al, 2015; Veasey, 2017), had its genesis in veterinary medicine (Dawkins, 2006)
Our results showed that Willingness to Participate (WtP) was significantly lower when there was an occurrence of new rake marks, the effect size was low, and coupled with the aforementioned ambiguity regarding the link between rake marks and negative affect, we recommend that more work is conducted on this measure before it is used as a welfare indicator
WtP in training sessions significantly decreased in the 3 days prior to a departure from good health’ (DGH) being diagnosed, suggesting that it could be used as an early indicator of decreased health, where in most facilities it may not be feasible for veterinarians to physically examine the animals every day
Summary
The objective measurement of animals’ affective states (Mason and Veasey, 2010; Hemsworth et al, 2015; Veasey, 2017), had its genesis in veterinary medicine (Dawkins, 2006). As reflected by the perception of ‘well-being’ in human society at the time, efforts were firmly focussed on measuring and improving the physical as opposed to psychological health of animals. An increase in both general husbandry standards and our knowledge of human and animal affective states led welfare scientists to consider behavioural and later cognitive measures of animal welfare. Support for “feelings-based” welfare definitions is strong, stipulating that health only impacts welfare if the animal’s feelings are affected (e.g., feeling sick), and encouraging research on identifying welfare indicators associated with health conditions (Mason and Veasey, 2010; Watters, 2014; Hemsworth et al, 2015; Clegg et al, 2017b; Veasey, 2017)
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