Characteristics and climate

Savannas - also known as tropical grasslands - are found to the north and south of tropical rainforest biomes. The largest expanses of savanna are in Africa, where much of the central part of the continent, for example Kenya and Tanzania, consists of tropical grassland. Savanna grasslands can also be found in Brazil in South America.

Elephants at a water-hole in Namibia
Elephants at a water-hole in Namibia

Savanna regions have two distinct seasons - a wet season and a dry season. There is very little rain in the dry season. In the wet season vegetation grows, including lush green grasses and wooded areas. As you move further away from the equator and its heavy rainfall, the grassland becomes drier and drier - particularly in the dry season. Savanna vegetation includes scrub, grasses and occasional trees, which grow near water holes, seasonal rivers or aquifers.

Plants and animals have to adapt to the long dry periods. Many plants are xerophytic - for example, the acacia tree with its small, waxy leaves and thorns. Plants may also store water, for example the baobab tree) or have long roots that reach down to the water table. Animals may migrate great distances in search of food and water.

The graph below shows average monthly temperatures and rainfall levels in the savanna region of Mali. Notice how the temperature and rainfall patterns relate to each other - the hottest temperatures come just before heavy rainfall, and the coolest time of the year comes just after the rains. This pattern is typical of savanna climates.

Monthly rainfall and temperature bar graph for the Savannah regionsWorld Meteorological Organisation, 2013