Play

I came downstairs yesterday morning and looked out the window, to see a doe and two fawns grazing on my lawn. Evidently they were finding something worth eating among the crabgrass. But the fawns weren't all that interested in breakfast. They'd nibble a bit then gambol -- i.e. jump around -- singly or together. They'd nuzzle the mother briefly, and she might nuzzle them back. At one point they both suddenly ran off into the woods. She just waited patiently until they came running back. They seemed to be testing or teasing her. Of course at some point she's going to have to let them go, but not yet. 

What I find curious about this is that the fawns couldn't possibly have been getting more calories from the occasional nibble at my lawn than they were spending running around and playing. It turns out that all young mammals play. They wrestle, race each other, pretend to hunt a blowing leaf or an insect. (Or, if they live with humans, a toy we give them.) Humans with their complex societies and imaginations engage in more complex play, inventing stories and situations and characters, but as the song goes, even the deer and the antelope play in their own way.

This takes up a lot of energy, and food isn't always in surplus, although it is right now for our deer population in the middle of a long, rainy summer. So any good biologist has to ask why evolution would favor such apparently wasteful behavior. The answer seems to be that mammals, with their complicated brains, don't have all their behaviors wired in from birth. They have to learn how to browse and hunt and escape predators and compete for mates and nurture their young, which means they have to practice before they do the real thing. They have to build the connections between brain and muscle, the patterns of movement and response, the ways of being in the environments in which they find themselves. 

In the end, the deer all learn to live pretty much the same way, depending on where they live. I suppose the white-tailed deer in the southern New England forest learn a somewhat different lifestyle from their cousins in Virginia or Michigan, but within a given setting they're all getting by in pretty much the same way. But we grow up with big differences, going down paths that start diverging from our earliest days. So we can end up in very different places and find it hard to really see each other across the valleys. This occurs to me now because I've been reading about the Civil War, which by the way isn't as much over as we thought. Now is the time for the Union to finally win it.