Wildebeest, particularly those involved in the Great Migration in East Africa, are known for their incredible annual migrations, during which millions of them move across the savannas in search of fresh grazing and water. Their ability to navigate this extensive journey is a fascinating aspect of their behavior, and while it's not completely understood, several factors contribute to how wildebeest know where to migrate:

1. Instinct: Migration is an innate behavior for wildebeest. It's hardwired into their genetic code as a survival strategy. The urge to migrate is triggered by changes in environmental conditions, particularly the rainy and dry seasons.

2. Rainfall and Grass Availability: Wildebeest follow the patterns of rainfall and the subsequent growth of fresh grasses. Rainfall is a key factor that influences the timing and direction of their migration. They move to areas where they can find the most abundant and nutritious grasses to feed on.

3. Social Learning: Wildebeest are social animals that live in herds. Younger individuals learn from the older ones in the group. Over time, the older, more experienced wildebeest in the herd guide the younger ones to the best grazing and water sources based on their collective knowledge.

4. Magnetic Fields: Some research suggests that animals like wildebeest might have the ability to detect Earth's magnetic fields, which could help them navigate over long distances. This is still an area of ongoing scientific study.

5. Visual and Olfactory Cues: Wildebeest may use landmarks and familiar scents to orient themselves during their migrations. Certain geographic features, such as rivers and mountains, can serve as cues.

6. Trial and Error: Wildebeest herds often explore new areas and adapt their migration routes based on the availability of resources. This trial-and-error process can lead to shifts in migration patterns from one year to the next.

7. Predator Avoidance: Migration also serves as a strategy to avoid predators. Moving in massive herds makes it harder for predators to single out individual wildebeest.

8. Climate and Seasonal Patterns: Wildebeest have evolved to synchronize their migrations with the changing seasons and climate patterns. As the dry season approaches, they move toward wetter areas with greener vegetation.

It's important to note that the Great Migration is not a fixed route but rather a dynamic and fluid movement that can vary from year to year depending on environmental conditions. These animals are highly adaptable and rely on their instincts and collective behavior to find the best food and water sources as they navigate the East African plains.