Madhumalai means old hills. Madhumalai Sanctuary, rich in bio-diversity and dense vegetation, is sandwiched between the Bandipur and Annamalai sanctuaries, and together the three form the Nilgiri Biosphere Reserve in the Western Ghats, with the Mysore-Ooty highway passing through it. It is situated at an elevation of 1000 metres and extends over an area of 321 sq. kms where lie the sanctuary between Kerala and Karnataka states. It was one of the first wildlife sanctuaries in the country and is home to the spotted deer, tiger, wild boar & sloth bear. Otters and crocodiles inhabit the Moyar River.