Over 80 species of mammals, 303 species of birds, 54 species of reptiles, 20 amphibians, 55 fishes, 101 species of butterflies, 57 species of moths, 45 species of coleopteran, 30 species of Odonata and numerous other forms of insects are found in NSTR.
The faunal composition represents the Deccan Peninsular zone of bio geographic classification of India. The diversity of geo-morphology and vegetation give rise to 29 multitude of habitats and ecological niches that support rich wildlife. Most of the NSTR is covered with open forest vegetation and forms an ideal habitat for wild animals.
The topography of the sanctuary enables occurrence of varied micro & macro habitats to shelter variety of animals. The moist upper plateaus, river Krishna with lofty hill slopes on either sides, numerous hill streams, valleys and deep gorges, rock shelters, wood lands, bamboo forests contribute to the existence of a variety of wildlife species.
Under the Zoo-Geographic classification, this area comes under Indo-Malayan region (Cis-Gangetic sub-region) - native to the true Indian fauna like the Nilgai, Black buck and four horned antelope etc.
The steep vertical scarps are home to numerous raptors like honey buzzard, black eagle and hawks. These forests have only the grey jungle fowl. Among the other birds represented are Grey Hornbill, Malabar whistling Thrush and Paradise fly Catcher etc. The presence of numerous streams, dense foliage, wild flowers, woodland edges and damp patches attract numerous colorful butterflies including large Oak blue, Black Rajah, Great Egg fly, Blue Pancy etc.