Sixty-one species of mammals live beneath the towering peaks of the Teton Range. They are found in each of the four major communities in the park: alpine, forest, sagebrush flats, and wetlands. Mammals have two characteristics that separate them from other animals. They have hair and they nurse their young. Mammals also have other characteristics that allow them to thrive in almost any environment. They are warm-blooded relying on metabolism to maintain a constant body temperature instead of their surroundings. Mammals have well-developed sensory systems and specialized teeth that allow them to find and eat different foods. They can climb, swim, run, glide, and fly allowing mammals to inhabit a variety of niches in every ecosystem. Mammals also focus their energy to raise only a few young to ensure their survival rather than produce vast numbers of offspring. These characteristics allow mammals to adapt to almost every environment found on Earth.