Each year, over 1.5 million Wildebeest travel 1,000km in a huge loop across Tanzania in search of water and vegetation. This Great Migration follows these Wildebeest, accompanied by hundreds of thousands of zebras and antelopes, around the Serengeti and into the Masai Mara ecosystem. The animals pass through the Ngorongoro Conservation Area, the Maswa Game Reserve, the Grumeti Game Reserve, Ikorongo Game Reserve during their trek through the Serengeti National Park. During this journey, the grazing prey can fall victim to predators like lion, leopard, cheetah, hyena, wild dogs, and crocodiles, as well as succumbing to injury or sickness. By following weather patterns and the movement of the rains, the Wildebeest are able to find plentiful grass and water to keep their herd thriving. While it is unknown by scientists how the animals know exactly where to go, it has been suggested that the animals follow the growth of vegetation and can sense rain more than 50km away. This evolutionary advancement helps the Wildebeest to continue this age-old migration and ensure the survival of not only their herd, but the entire ecosystem that depends on this phenomenon. The Great Migration is considered the largest herd movement of animals on Earth. Researchers have recorded up to 1,000 animals per km², and the circular migration can even be seen from space!
Though the migration is ever-moving, we can begin to understand its circular motion through the early months of the year (January-March) when female Wildebeests give birth to around 400,000 calves over the course of only two or three weeks. After reaching the eastern edge of the Serengeti and entering the Ngorongoro Conservation Area (though not the crater), the fertile lands offer suitable conditions for raising Wildebeest calves. During this period, the abundance of Wildebeest, especially newborn calves, provide predators like lion and cheetah who reside in the Southern and Central Serengeti with easy prey.
Following this birthing period, the herd moves northwest towards the Maswa Game Reserve and Central Serengeti, attracting some new friends - zebras and many species of antelope.