Because they use energy and water so efficiently, Little Pocket Mice can inhabit some of the driest and least vegetated parts of North America. They are abundant in deserts of the southwestern United States and northwestern Mexico, and readily inhabit coastal sage, shrub-steppe, and open grasslands in those regions. Learn more about the Perognathus longimembris, more commonly known as a Little Pocket Mouse, in this easy-to-read species overview by the Smithsonian's National Museum of Natural History.