As the dry season intensifies, the population moves further north and west toward Lake Victoria into areas where there is permanent water and thunder storms are most likely to occur out of season. Toward the end of the dry season in July most of the population have ended up in the Kenya Mara. The most impressive and probably the most reliable migratory event is the mass movement off the Serengeti plains that occurs at the beginning of the long dry season, typically May or June. The Burchell's Zebra , although outnumbered six to one by wildebeest in the Serengeti, are still obvious participants in the migration. They move in large aggregations, which consist of family units containing up to a dozen females and young, and bachelor herds of mainly immature males.
Mares also cooperate in defending the family and especially protect foals against predators.
This group-defense is so effective that hyenas prefer to hunt in packs for zebras, whereas they usually hunt singly for antelopes. The stripe pattern of every zebra is different, making individual recognition comparatively easy. While the great herds are in the shortgrass plains they are especially hunted by lions, cheetahs, hyenas and packs of African hunting dogs. African Hunting Dogs are mud and mustard colored with black and white patches and large, round ears. They live in packs of 6-20 animals and have ranges up to 800 sq kms.