The relevance of animal play for animal welfare

动物为什么玩耍是行为生物学中最经久不衰的谜题之一。玩耍似乎并没有以任何明显的方式帮助动物生存或繁殖。那么，它为什么会演变呢？这个问题到目前为止还没有得到广泛接受的答案。另一个相关的问题是，玩耍是否可以更好地理解农场动物的福利。动物通常只在食物和安全等基本需求得到满足的情况下才玩游戏，但这一规则也有例外。例如，削减小牛和小猫的牛奶配给会让它们感到苦恼，并使小牛比以前更少玩耍。令人惊讶的是，它让小猫花了更多的时间玩东西。我们需要理解这样的例外，才能知道游戏何时真正意味着良好的福利，也因为它们可能提供关于游戏为什么进化的线索。我特别感兴趣的假设是，玩耍动作看起来如此笨拙、夸张或鲁莽，因为玩耍对动物来说是一种安全的方式，会给自己带来麻烦，这样它们就可以学习如何摆脱麻烦。这将帮助他们培养应对危险挑战所需的身体技能，以及在这些可怕的情况下避免恐慌的情绪韧性。我的研究项目旨在回答以下一系列相关问题：游戏为什么进化，它能告诉我们什么关于动物福利，游戏对动物福利有什么影响？小猪是检验这些假说的理想物种。它们有丰富多样的游戏行为，科学界比其他养殖物种更了解猪的游戏，猪在玩耍的年龄被成群饲养。第一个实验将测试环境因素是否会导致动物增加玩耍--如果玩耍是一种准备方式的话--以及这是否解释了为什么玩耍有时会随着福利的恶化而增加。环境因素预示着动物未来可能会遇到危险的情况。随后的实验将测试花更多时间玩耍的动物是否真的会在面临危险情况时变得更熟练，情绪更有弹性。最后，我们将使用来自人类临床研究的认知测试来评估单个小猪的整体情绪，以测试情绪的变化是否与游戏的变化有关。这项研究对于所有对我们为什么玩耍感兴趣的人，以及寻求更好地了解动物福利的科学家和农民来说，都将是重要的。如果玩耍可以帮助小动物成为有能力和勇敢的成年人，那么找到鼓励玩耍的方法也会带来更好的福利，因为动物将更好地准备好面对压力事件，比如被处理或运输。在社会对人道对待农场动物的需求日益增加的背景下，这将有重要的应用。这项研究还可能带来更广泛的长期积极的社会结果，因为提高动物福利也可以通过各种方式与农民和消费者的福祉联系在一起。

Why animals play is one of the most enduring puzzles in behavioural biology. Playing does not seem to help animals survive or reproduce in any obvious way. So why did it evolve? There is as yet no widely accepted answer to this question. Another connected question is whether play can be used to better understand the welfare of farm animals. Animals usually play only if essential needs like food and safety are met, but there are exceptions to this rule. For instance, cutting the milk rations of calves and kittens makes them distressed, and makes calves play less than before. Surprisingly, it makes kittens spend more time playing with objects. We need to understand such exceptions to know when play truly indicates good welfare, and also because they might provide clues as to why play evolved. I am particularly interested in the hypothesis that play movements can look so awkward, exaggerated, or reckless because playing is a safe way for animals to get themselves into trouble, just so that they can learn how to get out of trouble. This would help them develop the physical skills they will need to cope with dangerous challenges, and the emotional resilience to avoid panicking in these frightening situations. My research program aims to answer the following set of related questions: why did play evolve, what can it tell us about animal welfare, and what are the effects of play on animal welfare? Piglets are an ideal species in which to test these hypotheses. They have a rich, varied repertoire of play behaviour, the scientific community understands more about play in pigs than in other farmed species, and pigs are housed in groups at playful ages. A first experiment will test whether environmental factors that signal that an animal risks encountering dangerous situations in the future lead to increase play - as they should if play is a way of preparing - and whether this explains why play sometimes increases as welfare gets worse. Subsequent experiments will test whether animals who spend more time playing do become more skilled and emotionally resilient when facing dangerous situations. Finally, we will evaluate the overall mood of individual piglets using cognitive tests derived from human clinical research, to test whether changes in mood are associated with changes in play. This research will be important for all interested in why we play, and for scientists and farmers seeking to better understand animal welfare. If playing can help young animals become competent and brave adults, then finding ways to encourage play will also lead to better welfare, as animals will be better equipped to face stressful events like being handled or transported. This will have important applications in the context of increased societal demands for humane treatment of farm animals. The research may also lead to broader long-term positive social outcomes, as enhanced animal welfare can also be tied in various ways to the well-being of farmers and consumers.