In what is one of the longest known migrations of African mammals, Burchell’s zebra (Equus quagga) have historically left the Okavango Delta to travel approximately 250 km to the more nutrient-rich Makgadikgadi grasslands that only become inhabitable during the rainy season. After concerns that diseases carried by wild animals were infecting cattle, ranchers in Botswana erected veterinary fences that obstructed the migration for 36 years before being removed in 2004. Remarkably, migration of the zebras resumed within three years of the removal of the fences. Given that the lifespan of a zebra is approximately 12 years, none of the zebras that embarked on the migration would have ever made this journey before. This surprising detail raises the question: did this zebra population rediscover an old migratory path, or is there an innate sense of memory guiding them?
I used data published to Movebank by Bartlam-Brooks et al. (2013) to visualize the movement of these migrating zebras both using a program called Dynamo and by animating the track of a single zebra over an animation of NDVI images.
Movement of Zebra Z6399 with NDVI changes. Animation created in ArcGIS
Full dataset of Movebank zebra data published by Bartlam-Brooks. Animation created with the Dynamo Animation Tool