Intro

I am a sucker for GIFs of animals at play. On my desktop, I keep a grainy black and white of two crows atop an old sedan during a blizzard, seen from above. Crow One walks along the trunk through an inch or so of snow, gives a little shimmy in its feathers, and turns back to watch its buddy. Crow Two is on the roof, laying sideways, and then it barrel-rolls down the sloping rear window, leaving first tracks in the accumulated powder. By itself, the action is mesmerizing, but the icing on the cake is Crow Two’s flair: Just as it starts to roll, it makes the slightest pause while on its back, feet in the air as if dead, seemingly for no reason but expression of style, like a surfer’s soul arch.

Play is superfluous. From an evolutionary standpoint, it makes no sense. Playing does not suggest you will be a better mate or parenting partner—indeed, it might suggest the