Grasslands are large swathes of flat or rolling ground dominated by grasses and inhabited by grazing mammals. Rainfall is moderate, but concentrated in one part of the year. As a result, upper soil layers are soggy and rain-saturated throughout the wet season, while deeper parts of the soil are dry year-round. Plants grow lushly during wet and warm periods, then go dormant in the dry or cold.

Two broad categories of grasslands are recognized – tropical and temperate.

Tropical Grassland Biome
Also called savannas, tropical grasslands are found at low latitudes. Rainfall is restricted to a few months of the year and followed by a prolonged dry season. Open grassland conditions are maintained by poor soils, repeated fires, or animal activity. All of these prevent the establishment of tree cover.

Savannas support abundant and diverse plant and animal communities, though a few species of grasses tend to dominate regionally. Herbivores and carnivores of stunning variety are well-represented, from tiny insects, lizards, mice and birds to majestic elephants, giraffes, zebras, lions and rhinos.

Temperate Grassland Biome
Temperate grasslands form at middle latitudes. Like savannas, seasonal droughts, fires, and grazing animals restrict tree growth. But temperate grasslands have more distinct seasons, hotter summers and colder winters, and less rainfall overall. Soils are thick and fertile, and the dominant grasses intermix with abundant flowers. Willow and cottonwood trees do grow, but just along rivers.

Animal life in the grasslands is rich and varied. Lush growth sustains an array of plant-eaters, and in turn many predators as well as numerous scavengers. Song and game birds, raptors, horses, gazelles, wolves, coyotes, prairie dogs, rabbits, deer, mice, skunks, snakes, grasshoppers, and spiders are all common grassland inhabitants.

Prairies are a type of temperate grassland that forms in wetter regions and supports tall grasses. Prairie grasses grow tall and thick, as much as several feet high. In dryer areas, short grass biomes called steppes grow.