Botswana's Okavango Delta and the Makgadikgadi Salt Pans are two ends of a 360-mile round trip zebra migration, the second longest on Earth. In this animation, shades of red show dry areas, green represents vegetation, and the dots show GPS tracked zebras. The zebras begin at the Okavango Delta in late September. After the dry Southern hemisphere winter, November rains signal it is time to begin their two-week journey to the Salt Pans. The zebras feast on nutrient-rich grasses all summer, and return to the Delta as the rain peters out in April.
Fences blocked this zebra migration from 1968 to 2004. After they came down, researchers began tracking zebras with GPS and discovered this migration. They compared the zebras' location to NASA satellite data of rainfall and vegetation, and they found that migrating zebras have quickly learned when to leave the Delta and the Salt Pans using environmental cues. Researchers then use these cues to predict when the zebras will be on the move, a powerful tool for conservation.