Over my 40 years of guiding in Africa it became quite evident to me why zebras have stripes: Whenever I watched lions attacking a group of zebra, I couldn’t keep my binoculars well positioned. Something kept disrupting my concentration.
So I decided to watch a kill without binocs. And the answer sprang out like the mud clumps flying into the air from the zebra’s hooves. The pack of zebra ran together away from the lion. They didn’t disperse like gazelle do from an attacking cheetah.
And this mesh of striping, like a kaleidoscope out of control, confused my focused view in the binocs and certainly would confuse a predator in the chase. Great defense! This notion of camouflage has been reaffirmed often in scientific as well popular journals.
But then not long ago, Phillip Ball in his fascinating book, Nature’s Patterns: A Tapestry in Three Parts argued that zebra striping is perfect for temperature control.
Ball posits that animal patterns which are oblique, like squares or triangles, increase body heat; and that nonoblique patterns like stripes and circles, decrease body heat.
Temperature control for the African savannah!
But now comes another notion. Two Scandinavian scientists have just published a report in the Journal of Experimental Biology arguing that the light refracted by the unique repeating pattern of thick stripes on a zebra actually … is a bug repellent.
Their experiments aren’t complete, but quite compelling. And it’s notable that there are no other successful horse-like creatures wild on the African savannah, and that domestic horses are very difficult to keep in Africa, because of the large number of flesh-biting bugs.
Seems to me it’s some combination of all of the above, and probably more that we haven’t yet discovered. Nature is multi-dimensional, multi-formated to place a creature perfectly into the sphere of things in which it lives.
We know, for example, that every zebra pattern is unique, like fingerprints. Although certainly unlike anything resulting from fingerprints, zebra’s seem to recognize each other at pretty great distances. We also know that inbreeding breaks up the even geometry of striping, merging and truncating stripes, and that maybe if given a choice, a nicely groomed stripe is the preferred date!
So, why do zebras have stripes? Because they wouldn’t be zebras without them!