Zebras in this region migrate between the Okavango Delta in northern Botswana and the Makgadikgadi National Park, which are over 200 km apart. The animals spend the dry season in the Okavango Delta, a unique wetland system that provides the zebra with forage and water throughout the dry season. Once the rainy season arrives, the zebras migrate to the grasslands surrounding the Makgadikgadi salt pans. These grasslands are nutrient and mineral rich, but have no permanent water supply, making them accessible to the zebras only when seasonal rains fill the ephemeral water holes. Zebra and wildebeest from two different migratory populations congregate in the Makgadikgadi grasslands during the wet season, forming huge herds that can be thousands strong.