Variable rainfall, grassland sprinkled with tall trees, and hardpan ground characterize the temperate Savanna biome. It can be found most famously in the plains of Africa, but parts of Florida, Brazil, Australia, and India belong to this biome as well. It is a mixture of prairie land and forest, but it has unique characteristics as well.
The temperature on the Savanna varies little from season to season, averaging a warm 68º F (20º C) over the year. Rainfall, though, varies drastically. The wet season lasts 6 - 8 months, dropping most of the area's 20 - 60 inches (60 - 150 cm) of rain in a short period of time. The hard ground's impermeability means the precipitation makes temporary puddles that only slowly feed ground water. In the dry winter months, drought overtakes the terrain, and water sources evaporate. Therefore, animals and plants have adapted to survive these exaggerated conditions. Some birds migrate to wetter areas, while some rodents go into a dormant state underground.
Trees of the Savanna have little biodiversity. Acacia and Baobob trees dominate the otherwise straight horizon line. These trees have flattened tops because grazers, like giraffes, nibble the lower branches. Other African mammals use the trees for shade and water. Elephants, zebras, water buffalo, ostriches, hyenas, warthogs, hippopotamus, gazelles, and leopards are famous members of this ecology. There is much biodiversity among herbivorous grazers and carnivorous predators.
The tropical Savanna biome is in a state of flux. Elephants could create grassland out of forest by trampling trees. Fire actually helps to preserve the Savanna. Dry grasses are easily ignited by lightning, and the swift burning fire sweeps the steppe. Birds and large animals have evolved to outrun the fire, while rodents burrow deep enough to withstand the heat. Even grasses store their water supply in their roots, rather than their blades, so they are not killed by a blaze. The fire moves too quickly to damage trees, so can safely germinate seeds of some species.
