A warm tropical grassland with scattered trees. It gets enough rain for thick grass but has a long dry season, and fire and grazing animals stop the trees forming a closed forest.

When does the great migration happen?

All year round. The herds are usually on the southern Serengeti plains for calving around the start of the year, move north and west as the land dries, reach the northern Serengeti and Maasai Mara in the middle of the year and return south with the rains. Timing varies with rainfall.

A rocky outcrop of ancient granite rising from the plains. Kopjes provide shade, water and shelter for many animals, including lions and leopards.

Why are fires important on the savanna?

Fires clear dead grass, recycle nutrients and kill many young trees, keeping the landscape open. Savanna grasses regrow quickly afterwards, providing fresh food for grazers.

Can I explore a savanna in the app?

Yes. You can land on a savanna modelled on the Serengeti and explore its grassy plains, acacias and kopjes in interactive 3D.

Endless grass, flat-topped acacias and the greatest wildlife show on Earth

Savanna

3D landscape · Serengeti, Tanzania

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A savanna is a warm grassland with scattered trees that never close into a forest. Savannas lie mainly between the tropical rainforests and the deserts, where there is enough rain for grass to grow thickly but a long dry season, fire and hungry animals keep trees in check. They cover a large share of Africa and are also found in South America, India and northern Australia. In this app you can land on a savanna modelled on the Serengeti in Tanzania and explore it in interactive 3D.

The Serengeti ecosystem stretches across northern Tanzania and into Kenya, where it continues as the Maasai Mara. Its name is often said to come from a Maasai word meaning endless plains. Each year more than a million wildebeest, along with zebras and gazelles, follow the rains around this landscape, pursued by lions, hyenas and crocodiles. Serengeti National Park became a UNESCO World Heritage Site in 1981.

Key facts

Model landscape: Serengeti, TanzaniaIncluding Serengeti National Park and surrounding reserves
Serengeti National Park: About 14,750 km²The wider ecosystem is roughly twice as large
Typical rainfall: ≈ 500–1,300 mm a yearVaries widely between savannas; concentrated in a wet season
Seasons: Wet and dryIn the Serengeti, short rains around November–December and long rains around March–May
Migration: Over a million wildebeestJoined by hundreds of thousands of zebras and gazelles
Signature trees: AcaciasMany African species are now placed in the genus Vachellia
Rocky islands: KopjesGranite outcrops rising from the plains
Share of land: Roughly a fifth of Earth's landA commonly quoted estimate for savannas and similar grasslands
World Heritage: Since 1981Serengeti National Park is a UNESCO site

Climate: wet and dry seasons

Savannas are warm all year, but rain comes in seasons. As the tropical rain belt moves north and south of the equator through the year, a savanna gets a wet season of frequent storms and a long dry season when little or no rain falls. In the Serengeti, the short rains usually arrive around November and December and the long rains around March to May, though their timing and strength vary from year to year.

The difference between seasons transforms the landscape. In the rains, the plains turn green, water collects in pools and grazing animals give birth. In the dry months, grass turns golden and then brown, rivers shrink and animals must travel to find water and food. Rainfall also varies across the Serengeti itself, with the south-eastern short-grass plains drier than the wooded north and west.

Grasses, acacias and kopjes

Grass is the foundation of the savanna. Many savanna grasses use a type of photosynthesis, called C4, that works well in heat and bright sunlight. They grow from the base rather than the tip, so they can regrow quickly after being grazed or burned. The rich soils of the southern Serengeti plains, enriched by ash from nearby volcanoes such as those of the Ngorongoro highlands, grow short, nutritious grasses that draw the migrating herds.

Acacia trees, with their flat, umbrella-shaped crowns, are the classic savanna tree. Many have long thorns to deter browsers, and the whistling thorn houses colonies of ants that swarm out to defend it. Baobabs, sausage trees and fig trees also grow in places. Rising from the grass are kopjes, outcrops of ancient granite exposed as softer surrounding rock wore away. They collect water, shade and soil, and they serve as lookouts and dens for lions, leopards, hyraxes and many other animals.

Fire

Fire is a natural and essential part of most savannas. During the dry season, the dead grass becomes fuel, and fires, started by lightning or by people, can sweep across large areas. Grasses survive because their growing points are close to or below the ground, and many savanna trees have thick bark. Fire clears old growth, returns nutrients to the soil and kills many young trees, helping to keep the landscape open.

After a burn, fresh green shoots attract grazers, and birds follow fire fronts to catch fleeing insects. Park managers often use controlled burning to manage habitat and reduce the risk of larger, hotter fires late in the dry season. Scientists see fire, rainfall and grazing together as the main forces that decide whether a patch of land becomes grassland, savanna or woodland.

The great migration

The Serengeti's wildebeest migration is a year-round loop rather than a single journey. Around the start of the year, the herds gather on the southern short-grass plains, where most calves are born within a few weeks of each other, so many that predators cannot eat them all. As the plains dry out, the herds move north and west, and through the middle of the year they head into the northern Serengeti and Kenya's Maasai Mara. With the return of the short rains, they move south again.

The crossings of the Grumeti and Mara rivers are the most dramatic moments, as herds plunge into fast water where Nile crocodiles wait. The exact route and timing change each year with the rains. The wildebeest population grew sharply in the 1960s and 1970s after the cattle disease rinderpest was brought under control, and it is now usually estimated at well over a million animals.

Why zebras and wildebeest travel together

Zebras tend to eat the taller, coarser parts of grasses, while wildebeest prefer the shorter, leafier growth beneath. Moving together, the two species can use the same pastures with less competition, and many eyes help spot predators.

Grazers, predators and elephants

Savannas support an extraordinary range of large mammals. Grazers such as wildebeest, zebras, buffaloes and gazelles eat grass, while browsers such as giraffes, impalas and dik-diks feed on leaves and shoots. This variety supports predators, including lions, which live in prides; spotted hyenas, which are skilled hunters as well as scavengers; leopards; cheetahs, the fastest land animals; and African wild dogs. Vultures, termites and dung beetles recycle what is left.

African elephants are ecosystem engineers. They push over trees, strip bark and break branches, which opens up woodland and helps maintain grassland. They dig for water in dry riverbeds, creating drinking holes for other animals, and spread seeds in their dung over long distances. Termites are engineers too: their mounds enrich the soil and create patches of different plants across the savanna.

Savannas elsewhere and conservation

Savannas exist on several continents. In South America, the Cerrado of Brazil is one of the most species-rich savannas in the world, and the Llanos of Venezuela and Colombia flood seasonally. Northern Australia has vast eucalyptus savannas, and parts of India and South-east Asia have savanna landscapes too. Each has its own plants and animals, but they share the same pattern of seasonal rain, grass and fire.

Savannas face pressure from farming, the spread of settlements, fences and roads that cut migration routes, poaching and climate change, which may alter rainfall patterns. In the Serengeti, protected areas, community conservation schemes, anti-poaching work and tourism income all help to protect wildlife. Researchers stress that keeping the migration routes open across the wider ecosystem, not just inside the park, is essential.

Surprising facts about Savanna

Most wildebeest calves are born within a few weeks of each other, which overwhelms predators and lets more calves survive.
The Serengeti wildebeest population grew several-fold after the cattle disease rinderpest was controlled in the 1960s.
Some acacia trees employ ants as bodyguards, giving them shelter in swollen thorns in return for protection.
Fire helps keep savannas open; without it, many would slowly turn into woodland.
Elephants can turn woodland into grassland by pushing over trees.
Zebras and wildebeest often travel together because they prefer different parts of the same grass.

Frequently asked questions

What is a savanna?: A warm tropical grassland with scattered trees. It gets enough rain for thick grass but has a long dry season, and fire and grazing animals stop the trees forming a closed forest.
When does the great migration happen?: All year round. The herds are usually on the southern Serengeti plains for calving around the start of the year, move north and west as the land dries, reach the northern Serengeti and Maasai Mara in the middle of the year and return south with the rains. Timing varies with rainfall.
What is a kopje?: A rocky outcrop of ancient granite rising from the plains. Kopjes provide shade, water and shelter for many animals, including lions and leopards.
Why are fires important on the savanna?: Fires clear dead grass, recycle nutrients and kill many young trees, keeping the landscape open. Savanna grasses regrow quickly afterwards, providing fresh food for grazers.
Can I explore a savanna in the app?: Yes. You can land on a savanna modelled on the Serengeti and explore its grassy plains, acacias and kopjes in interactive 3D.

Keep exploring

The landscapes in Ember’s Universe are procedural 3D scenes modelled on real places. The landforms, plants and light follow the real thing, but the details are generated, not mapped.

Sources