Answer: B) Wildebeest from Tanzania to Kenya Explanation: The longest mammal migration in the world is the annual migration of wildebeest from the Serengeti National Park in Tanzania to the Masai Mara National Reserve in Kenya. This migration is over 1,800 miles long and involves more than 1.5 million wildebeest, hundreds of thousands of zebras, and other animals. Every year, the animals make this incredible journey in search of fresh grass and water.