Animal species do inhabit this biome, and have made special adaptations that ensure their survival. For example, the kangaroo rat never drinks, getting its moisture from the food it eats. Insects and reptiles are common, but large mammals are not. This biome is located in the tundra climate zone, which is only in the Northern Hemisphere. The growing season here is too short and the climate too cold to support tree growth.
Arctic tundra is a formation class which has a brief summer of long days and short or absent nights.
Permafrost , permanently frozen soil, is present, and its upper layer melts in the summer creating marshy conditions over wide areas. Decomposition of dead plants is slow due to cold temperatures, so a thick organic layer of topsoil develops here. Tundra plants are small, low-lying plants, and consist of sedges, grasses, mosses, lichens, forbs, and occasionally the dwarf willow, a very low shrub. Alpine tundra is the other formation class that occurs above the treeline at high elevation, and resembles arctic tundra in appearance. However, because of the close proximity to trees at lower elevation, some conifer trees, like spruce and fir can be found in alpine tundra.