This document defines and describes the key characteristics of tundra biomes. It identifies the three main types of tundra: Arctic, Antarctic, and alpine tundra. Arctic tundra circles the North Pole and occurs in cold northern regions. Antarctic tundra is similar but located in the Southern Hemisphere around the South Pole. Alpine tundra occurs at high elevations globally. The document outlines the simple vegetation, short growing seasons, low biodiversity, and permanently frozen soils (permafrost) that are signatures of all tundra biomes. It provides examples of plant and animal adaptations to the harsh tundra environment and notes threats from climate change such as permafrost thawing.