Topi
These medium-sized antelopes migrate every fall on the South Sudan. They’re normally pale yellow and brown, and they turn into a viridescent shade during the migration. This change in color helps them migrate, as millions of them travel across the lowlands around the White Nile. This is different than other antelope migrations.
According to Atlas Obscura, “Topi are an extroverted species that have been known to socialize with animals beyond their species, like wildebeests, zebras, and even ostriches. They are notoriously picky eaters: the topi only grazes on grass and can go without water for long periods, so long as the grass is fresh and well-hydrated. Perhaps weirdest of all, female topis can delay birth if they sense they’re in danger.” The Sudd wetland is currently on the UNESCO World Heritage Site. This is where the Topi migrate (Atlas Obscura).