Ancient Migration Regained as Fences Come Down

Zebras migrating in Botswana (Photo: Robert B. Haas)

For decades, a network of veterinary fences disrupted traditional wildlife migration routes in Botswana, in southern Africa. The idea was to keep wild buffalo from transmitting disease to domestic cattle.  But the horrific result was that dead zebras, giraffes, wildebeests, and other species sometimes piled up by the thousands along the fence lines, unable to find their way to grass or water.

Then in 2004, some key fences came down, and what seemed to be a kind of miracle happened. Zebras whose parents and grandparents were too young to have experienced the old migratory route nonetheless picked up as if the fences had never happened.

They made their way across 180 miles of sparse, flat countryside from the Okavango Delta south to the Makgadikgadi Salt Pan, just in time for the November rains to fill the potholes and drive up a fresh crop of grass for grazing. Then, when the salt pan dried out again, they turned around and walked 180 miles back to the Okavango Delta.  It was a remarkable instance of the irrepressible power of nature.

Now, in an article in the Journal of Geophysical Research–Biogeosciences, a team of co-authors, combining data from ground level and from 220 miles up in geostationary orbit, has set out to discover just how the zebras did it  …  To read the rest of this story, click here.