The Great Migration

There are few natural spectacles on earth which can compete with the Great Migration – Tanzania’s greatest show. The largest land-based wildlife movement on the planet, around two million wildebeest, zebra, gazelle and antelope travel hundreds of miles from their calving grounds in the Serengeti to Kenya’s Masai Mara, before completing the loop to repeat the cycle over again.

The sheer numbers are astonishing; anywhere between 1.2 and 1.5 million wildebeest and 300,000 zebra travel in mega herds, snaking columns so huge that they can be seen from space, with up to 1,000 animals packed into every square kilometre and lines of wildebeest that can stretch up to 25 miles long.

Driven by the need for water and fresh grazing, these mega herds brave countless dangers along the way before the best-known part of the Tanzania wildebeest migration, the hazardous Mara River crossing. Beset by predators, hunger, thirst, exhaustion and injury, the herds thunder down the banks in a frenzy, braving the deep water with its strong currents and hidden crocodiles, hooves flailing in a desperate attempt to escape on the opposite side.

It’s a sight you’ll never forget and, unsurprisingly, a bucket list experience for many visitors to Tanzania and Kenya who book far ahead for a chance to glimpse this life-or-death struggle.

But there’s more to Tanzania’s Great Migration than this dramatic scramble; here’s everything you need to know before you book.

The Great Migration isn’t a single event but a continuous annual cycle which sees millions of animals move north through Tanzania from the Serengeti into Kenya’s Masai Mara, before returning south once more and completing the circuit in time for their young to be born.

Travelling in a clockwise pattern, the herds cover as much as 1,800 miles during the 12-month migration.

The highlight is watching the dramatic Mara River crossing, which takes place mainly from June to August in Tanzania as the herds brave the plunging descent to raging crocodile-infested waters, as well as the predators awaiting them on the banks, in the hope of finding new grazing on the other side. This is also the busiest time of year, and you’ll need to book well in advance to have a chance of experiencing it.

But you can also plan holidays to enjoy other parts of the Great Migration cycle, from the magical chance to see the first babies of calving season to the herds crossing the narrower Grumeti River, and the return crossing from Kenya to Tanzania. Here’s an overview of what to see when.

December – February

This is the peak of calving season when hundreds of thousands of wildebeest and zebras are born, as the large herds graze on the Ndutu plains in the Ngorongoro Conservation Area in the southeast of the Serengeti. The presence of the vulnerable young also attracts lions, cheetah, hyenas and other predators looking for easy prey.

March – May

This period sees Tanzania’s heaviest rainfall, and the herds begin to move across the Serengeti through the western corridor, beginning their journey north ahead of the upcoming dry season. With plentiful water sources, lush undergrowth and bad travelling conditions, this isn’t the best time to visit Tanzania however.

June – July

The peak of the Tanzania wildebeest migration, this is the experience which most people are hoping for when they plan to see the Great Migration in Tanzania – but you can expect to share it with countless others. June starts with mating season, known as the rut, before the herds continue north.

After surviving the Grumeti River crossing, they reach the perilous Mara River for the dramatic final stretch of their journey into Kenya. Risking anything from broken legs to hungry crocodiles and hunting lions, the herds may spend hours (or days) waiting before an unspoken signal sees them stampeding into the riskiest part of the entire epic migration.

August – September

The stragglers may still be crossing from Tanzania in August, depending on the year’s weather and movement of the herds, but the majority have crossed into Kenya by this point to enjoy the new grazing. Although there’s still plenty to see in Tanzania’s reserves, consider adding some time in Kenya instead of a Serengeti migration safari to see the herds in the Masai Mara.

With the short rains beginning in Tanzania, the herds begin their journey back south towards the Serengeti, crossing the Mara River slightly further east. As water levels are usually lower, it’s less perilous for the herds than on the north-bound journey, although never risk-free.

During this period, they’ll make their way back towards the Ngorongoro Conservation Area, completing the circle they began 12 months ago, in time for calving season.

The long and hazardous journey is driven by the herds’ search for grazing and water, with the animals following the rains to ensure new food sources. No-one is quite sure how the millions of wildebeest and other plains animals know which way to go, with different theories as to explain this astonishing annual feat. Increasingly erratic weather patterns, including shorter periods of rain, mean that timings are also becoming more unpredictable and the exact locations can also change from year to year. But with expert guides to track the migration, you’ll still have a good chance of seeing the herds, as well as the other highlights of the Serengeti.

The image of crocodiles dragging unfortunate wildebeest into the waters of the Mara River is one of the unforgettable sights of every Great Migration, but these predators are only one of the dangers faced by the herds.

The animals are also targeted by various predators along the way, especially big cats but also wild dogs and hyena. While these will stay in their smaller territories rather than pursuing the herds for hundreds of miles, the slow, the sick, the ill or the unlucky will be picked off relentlessly during the journey.

But there are other hazards, including exhaustion, thirst and malnutrition, as well as during stampedes where the sheer numbers and frenzied charge mean the weaker members may be injured. They also face the risk of drowning, particularly as they cross the Mara River. The strong currents and deep water mean that the often exhausted animals simply don’t have the energy to make it across to the other side.

In all, hundreds of thousands will die in the months travelling from the Ndutu Plains to the Masai Mara – around a sixth of the wildebeest which set out will fail to return. But the natural cycle ensures their numbers are replaced in the calving season, maintaining the herds, their predators and the landscape year after year.

Although you’ll see various species in the enormous column of animals on the Great Migration, there are three main groups whose different feeding habits dictate their movement. Zebras eat the taller grasses, while wildebeest feed on the shorter shoots which remain so the two species travel well together – zebra have keen eyesight and hearing, while wildebeest have an impressive sense of smell, so staying relatively close together gives both species an advantage against predators.

Lastly come the gazelles, including Thomson’s gazelles which graze on the remaining grass and plants close to the ground. A perfect way to keep balance across the plains as they complete their journey.