Grassland biomes consist of large open areas of grass. Trees can be present, but they are infrequent. The animals found in grasslands range from African elephants (Loxodonta africana) to various species of prairie dogs (Cynomys spp.).

Low rainfall, wildland fires, and grazing by animals are three factors that maintain grasslands. In grassland regions, the climate is ideal for the growth of grasses only. The low precipitation rates are enough to nourish grasses but not enough for a forest of trees. Frequent fires also play a role in maintaining grassland ecosystems. Grasses are well adapted to grow back after a fire. Grassland animals are also prepared for fires, fleeing or burrowing underground to wait out the flames. Large animals, such as African elephants, can also trample the ground and discourage the growth of trees.

The two distinct types of grasslands are savannas and temperate grasslands. These two types of grasslands may look similar, but they differ in some significant ways. For example, elephants are found in African savannas but not in the temperate grasslands of the United States. In contrast, burrowing animals, such as prairie dogs, are commonly found in temperate grasslands. Temperate grasslands also are known to have richer soils than savannas.

Savannas are present in areas that have a warm climate with a rainy season and a dry season. Most of the precipitation falls during just a few months of the year. This results in a long dry season that inhibits the growth of trees. Savannas and their abundant wildlife are famous in Africa, but savannas can also be found in South America, Asia and Australia.

Temperate grasslands, on the other hand, are known for their rich soil that yields abundant growth of grasses. Temperate grasslands are found in places such as North America and Eastern Europe.

Humans have had a dramatic impact on the grassland biome. Because temperate grasslands have rich soil, most of the grasslands in the United States have been converted into fields for crops or grazing land for cattle. The loss of grasslands due to agriculture has affected several species, including monarch butterflies (Danaus plexippus). During their long migration to Mexico, the butterflies depend on the grasslands’ wildflowers for food. Consequently, monarch butterfly populations have begun disappearing as more and more grasslands have been converted into farmland.

In the African savannas, illegal hunting has resulted in the loss of many large animals, including elephants. The elephants protect the grasses of the savanna by crushing trees and shrubs. Without large animals around to stomp down the trees, they can more readily overtake the grasses, causing savannas to turn into forests. The resulting loss of the grasses would mean less food for grazing animals such as Grevy’s zebras (Equus grevyi).