The Grizzled Squirrel Wildlife Sanctuary (GSWS), also known as Srivilliputhur Wildlife Sanctuary, was established in 1988 to protect the Near threatened grizzled giant squirrel (Ratufa macroura). Occupying an area of 485.2 km2, it is bordered on the southwest by the Periyar Tiger Reserve and is one of the best preserved forests south of the Palghat Gap. The sanctuary covers in western Tamil Nadu, South India in the eastern water-shed of the Western Ghats and consists of high hills and valleys, with a number of peaks reaching up to . Geography The Grizzled Squirrel Wildlife Sanctuary is located from 9° 21' to 9° 48' N and 77°21' to 77°46' E. The sanctuary lies mostly in Virudhunagar district especially in Srivilliputtur and partly in Madurai district. The sanctuary is bounded to the north by the Andipatti hills, south by Tirunelveli District, east by Srivilliputhur and Rajapalayam towns and west by Theni town and Theni District. It is the eastern boundary for the Periyar river watershed. This sanctuary is contiguous to Periyar Tiger Reserve on the south western side and the Megamalai Reserve Forest on the north western side and Its southern limit is contiguous with the Sivagiri Reserved Forest of Tirunelveli Forest Division. The elevation ranges from in the plains and rises to the highest peak, Kottamala, at . Average annual rainfall varies between - in different areas of the sanctuary. Water sources for the sanctuary are the Kallar and Mullaperiyar Dams and the Periyar, Naragaiar, Pachaiar, Mangar, Kovilar and Pairakudraiar rivers. The underlying rock throughout the area is granitoid gneiss formation. The lowest altitudes have a mixture of quartz and quartzite. Fauna In addition to grizzled giant squirrels, other animals seen here are Bengal tiger, bonnet macaque, common langur, elephants, flying squirrels, gaur, Indian giant squirrel, leopard, lion-tailed macaques, mouse deer, Nilgiri langur, Nilgiri Tahrs, palm civets, porcupine, sambar, slender loris, sloth bear, spotted deer, tree shrews, wild boar and wild cats. Resident and migrating elephants are common. The wildlife census in 2002 counted 156 elephants. There were more grizzled giant squirrels sighted in 2009 than in 2008. In 2008, a group of 30 lion-tailed macaques were sighted during the annual census, but in the 2009 census more than 45 lion-tailed macaques, including a sizeable number of young macaques, were sighted in a single group between Nagariyar and Periyakavu patch. Nilgiri Tahr have been sighted in the entire division starting from