Masai Mara is also known for the high density of lions that it has and when the wildebeests cross to Masai Mara, they are hunted down by predators  the big cats and this reduces the number of wildebeests that cross back to Serengeti.

During the Mara river crossing, the wildebeest migration involves a migration of over 1.5 million wildebeests and thousands of Thomson and grant’s gazelles and zebras during their way from Serengeti national park to the plains of Maasai Mara. The animals participating in the migration are said to migrate as they look for fresh grass and water, the Mara River crossing is the deadliest stage of the migration as the migrating herds enter the river infested by the deadly crocodiles. After crossing the river, the herds face off with the predators such as lions, leopards and cheetahs on the banks of the river. The whole grand event can be watched during Kenya wildlife.

By August, the herds have faced the challenge of crossing the Mara River and are spread throughout the Masai Mara’s northern region, with many remaining in the northern Serengeti. In years when the river is in full flow, the panic and confusion at the crossings — combined with waiting predators and surging currents — can cause massive loss of life. But, even in years of relatively gently flowing water, the crocs take their toll, not to mention the lions and other large predators that patrol the banks, ready to ambush any wildebeest that make it to the other side. There is no single crossing: at some spots, there are just a few individuals, while others see a mass of animals moving without break for hours.

1. Predators Hunt Newborns during Calving Season in Serengeti

The calving season usually occurs from February to late March, when about 8 000 wobbly babies are born every day. Because the babies can run as fast as their moms within 48 hours, there are very touching scenes of tiny wildebeest speeding along and of zebras nuzzling their foals.

But be warned: no aspect of the Gnu Migration is for the squeamish. Predators feast on newborns and you’ll likely witness action-packed scenes of calves being run down by cheetah or snatched by lions. The pressure of predators is one of the reasons why nearly half a million wildebeest are born so close together. It’s nature’s numbers game. While many become the prey that sustains lion prides, enough survive to secure the future of the great herds. It may be a well-worn cliché, but the Wildebeest Migration is truly what ‘the circle of life’ is all about.

2. Its Perpetual

Most people think that the Migration only takes place between July and October, but that’s not the case. It’s actually a fluid, year-round movement with various but equally exciting events. The popular river crossings usually coincide with safari’s high season (June to October), hence the perception that this is the only time of the year to see the Wildebeest Migration. Although the river crossings are absolutely riveting, they’re only a small part of this epic journey.

To understand this natural phenomenon, you have to ask, ‘Why do wildebeest migrate?’ Well, the Gnu Migration is dictated primarily by the wildebeest’s response to the weather. It’s triggered by East Africa’s rains, and the animals follow their ancient instincts in search of fresh grazing and water. This epic journey takes the wildebeest across the Masai Mara, all the way south into the Serengeti and to the edge of the Ngorongoro Crater, before circling up and around in a clockwise direction. Here’s a month-by-month breakdown:

3. The Gnus Don’t Migrate Together in One Big Herd

Yes, about two million wildebeest and zebra follow the rains on a 3 000-kilometre (1 900-mile) journey, but they don’t travel all together all the time. Half of them would starve if they did!

They split into what are known as ‘mega-herds’, which consist of thousands and thousands of individuals travelling on slightly different routes in more or less the same direction. After the rut (mating) season from about April to May, those that did not mate often break away from the others and form their own herds that travel through the central Serengeti. The animals form huge columns – sometimes up to 40 kilometers (25 miles) in length – that can be seen across the plains.

Members of mega-herds can be quite spread out, with the forerunners arriving at a new place sometimes a day or two ahead of the stragglers – kind of an ‘early warning system’ for safari guides.

4. It’s Unpredictable

In East Africa, the ‘long rains’ generally soak the ground in April and May, and the Serengeti plains spring to life with masses of sweet, delicious grass. This is the signal for wildebeest and zebra to start moving into the central Serengeti, mowing the abundant tender grass along the way.

Broadly speaking, this is exactly how it works. Except when the rains are late. Or early. Or if it rains again unexpectedly and some (or all) of the herds turn back to feast on the fresh new grass.

By June, the wildebeest and zebra should be in the Central Serengeti and getting ready for the toughest part of their odyssey: river crossings (about June to August). But not even the wildebeest know when they’re going to cross. Some arrive at the rivers and swim over immediately, while others might spend days hanging around grazing. Some even arrive and turn back to where they came from!

5. Wildebeest Crossings Are Popular, But Not for the Faint-Hearted

River crossings are considered the highlight of the spectacle: few other sights beat them for sheer drama and adrenalin value. Will crocodiles snatch the courageous gnu that leaps in first? Will the animals be able to scramble up the increasingly treacherous and slippery riverbank? Will weak or injured wildebeest be able to swim across at all?

Popular perception is that the wildebeest are galloping along at top speed and just crash into the water, following a sort of autopilot herd instinct. This isn’t the case at all. Often, a herd will reach the river at a casual, leisurely pace … and then hang out on its banks for days, frustrating the crocs and tourists alike.

Nobody knows how and why they suddenly decide to cross, but some sort of primeval signal is given. The first intrepid pioneers will then scuttle down the often very steep sides and rocky riverbanks. You will naturally be rooting for these brave forerunners, but you’ll likely witness heart-breaking moments too. An animal can often break a hind leg trying to climb a bank or lose its precarious grip and fall back down onto others, injuring them all. This is what makes a wildebeest crossing a true spectacle – the ecstasy and agony of survival, unedited, unfiltered, in raw true life.

Why do wildebeest migrate between Serengeti Tanzania and Maasai Mara Kenya

The 800 kilometer trek of the immense wildebeest herd is the largest mammal migration on earth. The timing of the migration coincides with greening of nutritious grasses on the short-grass plains during the wet season. These areas are safer because predators can be easily spotted making it an ideal place for calving. However, the plains dry and the wildebeest are forced to move in search of greener pastures in the western corridor. The northern extension of the ecosystem has the highest rainfall, but the grasses are least nutritious. This is the dry season retreat for the wildebeest, at least until the south becomes green again. The result is a clockwise movement from the south, west, north, and back to the south.

Serengeti National Park

The vast plains of the Serengeti comprise 1.5 million ha of savannah. The annual migration to permanent water holes of vast herds of herbivores (wildebeest, gazelles and zebras), followed by their predators, is one of the most impressive natural events in the world.

Outstanding Universal Value

Brief synthesis

In the vast plains of Serengeti National Park, comprising 1.5 million hectares of savannah, the annual migration of two million wildebeests plus hundreds of thousands of gazelles and zebras – followed by their predators in their annual migration in search of pasture and water – is one of the most impressive nature spectacles in the world. The biological diversity of the park is very high with at least four globally threatened or endangered animal species: black rhinoceros, elephant, wild dog, and cheetah.

Criterion (vii): The Serengeti plains harbour the largest remaining unaltered animal migration in the world where over one million wildebeest plus hundreds of thousands of other ungulates engage in a 1,000 km long annual circular trek spanning the two adjacent countries of Kenya and Tanzania. This spectacular phenomenon takes place in a unique scenic setting of ‘endless plains’: 25,000km² of treeless expanses of spectacularly flat short grasslands dotted with rocky outcrops (kopjes) interspersed with rivers and woodlands. The Park also hosts one of the largest and most diverse large predator-prey interactions worldwide, providing a particularly impressive aesthetic experience. 

Criterion (x):  The remarkable spatial-temporal gradient in abiotic factors such as rainfall, temperature, topography and geology, soils and drainage systems in Serengeti National Park manifests in a wide variety of aquatic and terrestrial habitats. The combination of volcanic soils combined with the ecological impact of the migration results in one of the most productive ecosystems on earth, sustaining the largest number of ungulates and the highest concentration of large predators in the world. The ecosystem supports 2 million wildebeests, 900,000 Thomson’s gazelles and 300,000 zebras as the dominant herds. Other herbivores include 7,000 elands, 27,000 topis, 18,000 hartebeests, 70,000 buffalos, 4,000 giraffes, 15,000 warthogs, 3,000 waterbucks, 2,700 elephants, 500 hippopotamuses, 200 black rhinoceroses, 10 species of antelope and 10 species of primate. Major predators include 4,000 lions, 1000 leopards, 225 cheetahs, 3,500 spotted hyenas and 300 wild dogs. Of these, the black rhino Diceros bicornis, leopard Panthera pardus, African elephant Loxodonta africana and cheetah Acynonix jubatus are listed in the IUCN Red List. There are over 500 species of birds that are perennially or seasonally present in the Park, of which five species are endemic to Tanzania. The Park has the highest ostrich population in Tanzania and probably Africa, making the population globally important.

Integrity

Serengeti National Park is at the heart the larger Serengeti ecosystem, which is defined by the area covered by the annual migration. The property is contiguous with Ngorongoro Conservation Unit, an area of 528,000ha declared a World Heritage Site in 1979. The entire ecosystem also includes the Maswa Game Reserve (2,200km²) in the south, Grumeti and Ikorongo Game Reserves in the east, Maasai Mara National Reserve in Kenya (1,672km²) to the north, and Loliondo Game Controlled Area in the west. This entire ecosystem is intact and no barriers hamper the migration. Serengeti National Park is sufficiently large and intact to ensure the survival and vigour of all the species contained therein, if maintained in its present state but does not, by itself, ensure the protection of the entire ecosystem. However, all other parts of the ecosystem do have a greater or lesser degree of protection. A potential threat is the plan to build a transport infrastructure through the Serengeti. This would essentially cut the ecosystem into two halves, with predictably negative consequences on the Serengeti. Adding Maswa Game Reserve and Maasai Mara National Reserve to the World Heritage List, or giving then the status of a buffer zone would further safeguard the Outstanding Universal Values of this property.

Another major potential threat to the integrity of the Park is the scarcity of surface water for the animals during dry years, as only one river (Mara) flows perennially through the Park. An extension of the Park boundary to reach Lake Victoria providing a corridor for animals to access water in times of drought is planned for the future to address this issue.

Protection and management requirements

The site has a well designated and partially demarcated boundary, and since 2009 funds have been allocated to demarcate the entire boundary. Its management is regulated by both international and government policies and legal obligations. The National Parks Ordinance Cap 412 of 1959 provides for Tanzania National Parks with the mandate to manage the site. In addition, The 1974 Tanzanian Wildlife Conservation Act and the 2009 Wildlife Conservation Act provide for both within the site and adjacent area protection of resources, respectively. A General Management Plan (2006-2016) has been formulated to guide the daily management of the site in a sustainable manner and is currently being implemented. The Plan provides guidance on how to execute the various activities within the park under four main Themes: Ecosystem Management, Outreach services, Tourism Management and Park Operations. The site has a reasonable level of human and financial resources for effective management, but as the activities expand, and more challenges emerge, the lack of sufficient resources remains a potential future constraint. The major management concerns include poaching, tourism pressure, wildfires, and lack of adequate capacity in resource monitoring. Another important management challenge is water: despite numerous sources of water during the rain season, there is only one perennial river (Mara) which is transnational. However, this river currently faces multiple human-mediated cross-boundary threats.

It’s hard not to be awed as you soar in a hot-air balloon with the sun rising behind you and wildlife stirring below.  

If you are visiting the Serengeti or the Masai Mara, you may witness the masses of wildebeest on the riverbanks as they prepare to plunge across on their Great Migration. Floating high above Tarangire, you might look down on the huge herds of elephant and large groups of buffalo.

For photographers, a hot-air balloon ride offers an opportunity to capture incomparable images of quietly grazing animals and the dramatic juxtaposition between land and sky. For the ultimate romantic experience, follow your hot-air balloon safari with a champagne breakfast in the bush. 

This excursion starts very early in the morning, to catch the sunrise. We encourage guests to pack layers, as it can be chilly in the air. Hot-air balloon excursions are also weather dependent. Balloons cannot go up if it is too windy or rainy. Make sure you book in advance to secure your spot. Balloon safaris are operated by third parties.

What is it all about?

You’ll be woken up before the crack of dawn and whisked away on a (very) early drive to the launch site. It can be quite chilly at this time of the morning – not to mention even cooler once you’re up in the air, so be sure to wrap up in a few extra layers. Arrive at your balloon and watch as your professional ballooner gets ready for your take-off. Be prepared for the sound as they gas up the balloon – it can be quite loud, so it’s not uncommon to get a fright! However, once you are in the air, it is mostly silent (save for the occasional roar of the gas) so you can fully appreciate the wonder of peacefully flying high above the plains.

How does it work?

Hot-air balloon safaris are extremely dependent on weather conditions. If it is too windy or rainy, the flight will be cancelled and you will have the option of receiving a full refund or rescheduling to another day (if possible). Booking well in advance is absolutely essential. This is not an activity that can be organized on the day. Due to the reliance on the weather, it is also not on offered throughout the year, so it’s best to make sure your agent is aware of your interest in this wonderful experience and have them book as far in advance as possible.

Can the Migration River Crossings be predicted?

No, not even the wildebeest know when they’re going to cross! Some arrive at the water and swim over immediately; some arrive and spend days hanging around grazing; some arrive and turn back to where they came from. We wish we could predict the crossings, but no-one can. This is why it is best to have as much time on safari as possible if you hope to see a river crossing.

What Month is the Wildebeest Migration?

Most people think that the Wildebeest Migration only takes place between July and October, but it’s actually an ever-moving, circular migration with various but equally exciting events that occur year-round. The popular river crossings usually coincide with safari’s high season (June to October), hence the perception that this is the only time of the year that the wildebeest are on the move or can be seen.

Where Does the Great Migration Start?

Because the Great Migration is a fluid, year-round movement of about two million animals across the Serengeti-Mara ecosystem, there are no defined start or end points. The Gnu Migration is triggered by East Africa’s rains and the animals follow an age-old route in search of fresh grazing and water. This epic journey takes the wildebeest across the Masai Mara plains in Kenya, all the way south into Tanzania’s Serengeti and the edge of the Ngorongoro Crater, before circling up and around in a clockwise direction.

Why Do Wildebeest Migrate?

It is generally believed that the Great Migration in Africa is dictated primarily by the wildebeest’s response to the weather. They move after the rains and the growth of new grass, essentially following a natural instinct to find food to stay alive. Some experts believe that the wildebeest are triggered by distant lightning and thunderstorms, but there is no scientific proof of it.