To swim or not to swim: An interpretation of farmed mink's motivation for a water bath

How an animal's behavioural needs can be met is a pivotal issue in the assessment of welfare for captive animals. The value of swimming water for farmed mink is an example of how scientific and societal questions relating to animal welfare can be answered. A number of studies have addressed the issue of the indispensability of swimming water for mink; however, so far with inconclusive evidence. In this paper, the results of these studies and related literature are reviewed. First, the biological definition of need is discussed. Subsequently, we will review effects of the presence, absence and the removal of swimming water on behavioural and physiological correlates of well-being including stereotypic and anticipatory behaviour and urinary cortisol. Thereafter we will discuss individual differences in the use of swimming water, the price animals pay for access to a water bath, and the effect of access to swimming water on juvenile play. Our critical review of the available literature provides several conclusions: mink's water bath use appears primarily related to foraging behaviour; if mink have not had prior experience with swimming water the lack of this resource does not lead to consistent changes in stereotypic behaviour or anticipatory responses; when mink have had prior experience with swimming water, removal of this resource can induce short-term stress; most mink work hard for access to a swimming bath and running wheel in consumer demand studies; individual mink differ in how much they value a water bath: some mink never use a swimming bath; swimming water is likely not an “innate” need but rather an incentive that induces its own motivation.