A Pepper Grinder Post

Why do White-tailed Deer have White Tails?

I went for a walk the other day.  It was a beautiful fall day.  We live in a development but the houses aren’t too close together, especially on two spurs that go back away from the main road.  We’re surrounded by trees and there is a fair amount of wildlife about.  It was on one of those spurs where I saw foxes in the wild for the only time in my life.  I was at about the same spot where I had seen the foxes, when I saw two White-tailed Deer.

deerI grew up in upstate New York where, except during hunting season, there were lots of deer around, so seeing two deer wasn’t a stunning experience.  On the other hand, I never get tired of watching those graceful creatures move.  They weren’t too scared of me.  They moved away from me at a quick walk at first, then started to run and leap a little when they reached the edge of the woods.

When I first saw the two does, they were facing me and they blended into the brown of the fallen leaves remarkably well.  When they were moving away from me, it was a different story.  If you ever wonder how White-tailed deer got their name, just look at one running away from you.  When the deer are frightened, up go the tails, revealing the large white undersides of those tails.  If it weren’t for those tails, I would have had trouble spotting the deer as they moved quickly away from me through the trees.  With the tails though, it was like someone running away from you with a spotlight pointed in your direction on his back.

According to the theory of evolution, as deer evolved over time, there would have been various mutations.  If mutations are happening frequently enough or over a long enough timespan to produce whole new species, it certainly seems reasonable to assume that there would have been deer without white tails.  (Perhaps there are some species of deer now that don’t have white tails, though looking at a Wikipedia article just now, I was left with the impression that all deer had some white fur on their tails and rumps, even if it wasn’t as dramatic as White-tailed Deer.)  In any case, according to evolutionary theory, the deer with the best survival rate would reproduce the most and would thus come to predominate.

white tailWhich brings me to the title of this piece: why do White-tailed Deer have white tails?  If I were a mountain lion chasing two deer, one of which had a light brown rear end that blended in with the forest floor, and the other of which had a bright white backside, guess which one I would chase?  Since we predators would be gobbling up more of the white-tails than the other deer, most deer should NOT have white tails by now.  And yet, the deer I have seen all my life have big bright white tails that are stunningly visible when running away from you.

I am on perilous footing here.   I am not a biologist and perhaps some evolutionary biologist could  tell me some theory about why having those bright white tails gives a survival or reproductive advantage to the deer that have it.

And yet, my point isn’t just about those white tails.  Look around at nature.  Look at the mind-numbing variety, look at the colors, look at the complexity.  It doesn’t look to me like something that happened by chance.  (Try dumping a thousand blocks onto the floor a thousand times and see what the results look like.)  It doesn’t even look like something that was designed by a utilitarian.  It looks like something that was designed by someone who was the world’s best geneticist, biologist, and engineer, but who was also an artist.  It looks like it was created by someone who, in the midst of all the practical considerations about how to make a deer, decided, on a fanciful notion, to give them bright white tails, and then laughed aloud at the idea.  It looks like it was designed by someone who loved beauty and loved creating things.

This isn’t meant to be a scientific argument.  If you want that, there are some excellent books about Intelligent Design.  One of my favorites is Darwin’s Black Box by Michael Behe.  This is just me musing and wondering, “Why do White-tailed deer have white tails?”