The Great Wildebeest Migration is often called the “greatest show on Earth,” involving over 1.5 million wildebeest, plus hundreds of thousands of zebras and gazelles, in a continuous, year-round search for fresh grazing and water. The vast majority of this epic journey occurs within the boundaries of Tanzania’s Serengeti National Park.
The Serengeti’s Annual Cycle
Unlike a simple “there and back” journey, the Migration is a fluid, clockwise circuit driven by seasonal rainfall
.
Largest on Earth: It is the largest land mammal migration in the world. It involves around 1.5 million wildebeest, accompanied by hundreds of thousands of zebras and gazelles.
The Distance: The animals travel a massive, year-round, circular route spanning roughly 800 to 1,000 kilometers (500 to 620 miles) as they continuously follow the rain and fresh grass.
Mass Calving: During the calving season (Jan-Mar) in the Southern Serengeti, approximately 500,000 calves are born, with as many as 8,000 being born each day for a few weeks in mid-February.
Quick Learners: Wildebeest calves can stand within minutes of being born and can keep up with the running herd within days. This is crucial for survival in the predator-rich calving grounds.
The Mortality Rate: The journey is ruthless; an estimated 250,000 wildebeest die each year from thirst, exhaustion, predator attacks, or drowning during river crossings.
No Leader: The herds have no single leader. Their movement is guided by a form of collective decision-making known as “swarm intelligence,” where the group acts in sync to find the best routes and overcome obstacles.
While the exact timing changes yearly, the herd follows a predictable cycle through the Serengeti plains and into Kenya’s Maasai Mara reserve, always returning to the calving grounds in the south.
I throw myself down among the tall grass
I should be incapable of drawing a single stroke at the present moment; and yet I feel that I never was a greater artist than now. When, while the lovely valley teems with vapour around me, and the meridian sun strikes the upper surface of the impenetrable foliage of my trees, and but a few stray gleams steal into the inner sanctuary, I throw myself down among the tall grass by the trickling stream; and, as I lie close to the earth, a thousand unknown plants are noticed by me: when I hear the buzz of the little world among the stalks, and grow familiar with the countless indescribable forms of the insects and
| Time of Year | Location in Tanzania | Key Event |
| December – March | Southern Serengeti Plains (Ndutu/Ngorongoro Conservation Area) | Calving Season: Over 500,000 calves are born within a few weeks, creating intense predator action. |
| April – May | Central & Western Serengeti (Seronera/Grumeti) | The Long Rains: Herds begin to move north, often pausing in the Western Corridor, where the first major river crossings occur at the Grumeti River. |
| June – August | Western & Northern Serengeti | River Crossings: This is the most famous part of the journey. The massive herd attempts the treacherous crossings of the Mara River into Kenya, battling strong currents and awaiting crocodiles. |
| September – November | Northern Serengeti & Maasai Mara (Kenya) | Grazing & Return: The herds graze in the far north before turning south again in October/November as the short rains begin, guiding them back to the southern plains. |
Why Tanzania is Key
Tanzania hosts the most crucial and prolonged stages of the Migration.
The Calving Grounds: The highly fertile short-grass plains of the south (Ndutu) are the essential starting point and end point of the cycle.
The Herd: Approximately 80% of the entire wildebeest migration cycle is spent within the Serengeti National Park boundaries.
Best Viewing: Because of this long tenure, Tanzania offers the best opportunities to witness various stages, including the dramatic calving and intense river crossings.