Author Lyall Watson, writing about the culture and habits of pigs, concludes that when young pigs play it is voluntary, random, and stimulated by novelty. “Jumping where there is nothing to jump over, running without going anywhere, fleeing when there is no enemy to flee from--all these are actions that lack any obvious function. They appear to be undertaken purely for pleasure.” Young wild boars chase windfall apples as readily as kittens chase balls of wool.

We call such behavior “play” and find no difficulty in recognizing it when we see it. It is easy to distinguish. An animal involved in play-fleeing or play-fighting looks very different from one seriously occupied in flight or fight. But it would be wrong to regard play just as something opposed to work. It is far more important than that.

Play is voluntary. You can’t make someone play or legislate play into being. A pig wearing a silly hat and jumping through a hoop isn’t playing. Play implies, pleasure, fun, and a definite lack of constraint. It’s something that comes more naturally to the young than it does to adults.

Play is almost certainly a complex collection of activities that are not just frivolous. The amount of time spent on it by young animals suggests that it is important; and a lack of it may impair the acquisition of vital social abilities. Play seems to be necessary for a healthy brain in pigs as well as people.