Animal Welfare: Could Adult Play be a False Friend?

Abstract

-There is no consensus regarding the functions of play. As play behavior is a characteristic of young stages of development, it has been suggested that the higher prevalence of adult play observed in domestic animals could be the result of their "neotenic retardation." Functional hypotheses have dealt with the long term benefits, such as "rehearsal," "motor training" for future adult competencies or "training for the unexpected." However, there is little consistent experimental evidence favoring a particular hypothesis. The present study aimed to test the functional significance of adult play as a potential reliable indicator of good welfare, a by-product of domestication or a tool for social cohesion. Observations of both a domestic species (the horse) and wild/captive animals (cercopithecids) confirm the literature data that show the greater prevalence of adult play in the domestic/captive situations. This convergence between a domestic and a wild species argue against the idea that adult play may be a mere product of domestication. Moreover, animals living in naturalistic situations had the same low level of adult play as observed in wild animals suggesting that captive/domestic animals do not play only because they are stress free or well fed. Play is not a reliable indicator of welfare: Horses and adult macaques that played the most were also those that exhibited the greatest signals of poor welfare as stereotypic behaviors. Furthermore, adult play was more frequent at times of social disturbances and instability. Adult play is a sign showing that the adult organism needs to evacuate stress.

Indicators of Horse Welfare: State-of-the-Art

“…Increased rates of yawning by horses were found following the administration of soothing products leading to muscular relaxation [137], but also in ambiguous or frustrating situations [115] or chronic diseases (e.g., [116]) and have even been related to the occurrence of SB/ARB [138]. In the same way, play has long been considered as an indicator of positive welfare [117], but increasing evidence shows a potential relationship with inappropriate living conditions (see [139] for review). Young horses express play exclusively [70] under favourable conditions (e.g., [119]), but play can also be triggered by social isolation [140].…”

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

“…For example, a look at Table 2 shows that a disproportionate number of the studies showing the unexpected association between increased play and worse welfare (cf. Line 3) focus on adult animals, and correspondingly, papers expressing skepticism about play as a welfare indicator often focus on adults too (Blois-Heulin et al, 2015;Hausberger et al, 2012;Sommerville et al, in press;Yamanashi et al, in press). Furthermore, where play has consistently been found to be associated with poor welfare in young animals, such as for object play in prematurely-weaned kittens, this points toward the perfect model systems in which to test corresponding hypotheses about the functions and developmental effects of play (e.g.…”

Context‐dependent individual differences in playfulness in male rats

“…Play behavior, exhibited in mammals and birds (Diamond & Bond, ; Spinka, Newberry, & Bekoff, ), has been gaining relevance as a promising indicator of positive emotions and welfare (Boissy et al, ; Held & Spinka, ; Oliveira, Rossi, Silva, Lau, & Barreto, ), though not all play at all ages may indicate positive affective states, especially during adulthood (Blois‐Heulin et al, ; Hausberger, Fureix, Bourjade, Wessel‐Robert, & Richard‐Yriset, ). Although definitions and hypotheses about the purpose of play vary considerably (Burghardt, ; Power, ), Burghardt identified a number of properties that define animal play, namely that play is performed recurrently, yet not stereotypically; it is initiated only when there are no fitness threats; it has a purpose in itself; it is not fully functional and in this respect is different from adult “serious” behavior.…”