The winters are cold and dry. The little precipitation does not support trees, but grasses and herbs are present in great abundance. Depending on the amount of rainfall, there are varieties of grasslands such as tallgrass, mixedgrass or shortgrass prairies and steppes. Grasslands support a large number of herbivores from antelopes, horses and bisons to mice, groundsquirrels and gophers. Deserts Deserts are places where there is less than 250 mm annual precipitation.
Plant cover is sparse, and characterized by drought tolerant brushes, succulent and annual plants.
The soil is very poor in nutrients, and the humus layer is absent or only weakly developed. There is 900-1500 mm of rain each year, with a pronounced wet or rainy, and an almost equally long dry season. The temperatures are high year long, which results in droughts during the dry season, when most plants die or dry out. Soils are relatively nutrient poor due to leaching out during the rainy seasons. Trees are widely spaced, and the majority of the vegetation is different species of grasses.