Play in juvenile mink: litter effects, stability over time, and motivational heterogeneity

Abstract

Mink are potentially ideal for investigating the functions of play: deleterious effects of early social isolation suggest a crucial developmental role for play; and huge numbers of highly playful juvenile subjects can be studied on farms. We collected descriptive data on 186 pairs from 93 litters, half provided with play-eliciting environmental enrichment objects in their home cages, to test three hypotheses: (1) play frequency is subject to litter effects; (2) relative playfulness is stable over time; (3) play sub-types share a single, common motivational basis. We found weak litter effects that were driven by stronger litter effects on general activity, and weakly stable individual differences in both total and rough-and-tumble play. Experimentally increasing object play did not inhibit rough-and-tumble play, showing these sub-types are not motivational substitutes. Frequencies of these sub-types were also uncorrelated, and changed differently with time of day and age, further supporting this conclusion.

Play and optimal welfare: Does play indicate the presence of positive affective states?

“…Since the functions and effects of play are likely to vary with species, the sub-type of play, age, and other factors (Ahloy Dallaire and Mason, 2016;Burghardt, 2005;Pellis, 1991;Sommerville and Connor, in press), it is thus also likely that the welfare significance of play will vary from one case to another as well: something also demonstrated by the literature on play in humans (Section 2). This has not been studied in depth in animals: as Table 3 shows, most studies either investigate one single sub-type of play or pool the different sub-types in their analyses.…”

“…Other qualitative aspects that might be revealing to measure include the intensity of play behaviour (e.g. Ahloy Dallaire and Mason, 2016;Foroud and Pellis, 2003), or preferences for different maneuvers in rough-and-tumble play (e.g. Himmler et al, 2013;Pellis and Pellis, 2009).…”

The physiology of play: potential relevance for higher education

“…Is play as essential as sleep for a normal healthy life? Like many other key physiological mechanisms, play can display a circadian rhythm (Ahloy Dallaire & Mason, 2016), further suggesting that play is in itself a physiological process and goes far beyond just being an enjoyable experience.…”

Stereotypic behaviours are heterogeneous in their triggers and treatments in the American mink, Neovison vison, a model carnivore

“…In terms of precisely what these strong motivations to interact represent, more research is needed (see below). However, we suspect that these motivations are not playful, because play in 10-12-month-old mink is rare (Ahloy Dallaire & Mason, 2016;Hansen et al, 1997); instead, we hypothesise that they are agonistic, as aggression in mink often develops around 5-6 months of age (Hansen, 1996) and sub-adult and adult males naturally compete over territory in the wild (Dunstone, 1993). Turning to whole-body SBs, like normal activity this type of behaviour was performed in locations away from neighbours.…”