Tamil Nadu is endowed with a rich bio-diversity. The hilly terrain of the Western Ghats, Dry deciduous forests, thorn forests, scrub, mangroves and wetlands occur in the dry tracts that occupy the plains and lower hills of most of the state. Moist deciduous and wet ever green forests as also shoal and grassland occupy most of the hills in the moister parts of the state, chiefly in the western ghats.

Tamil Nadu has the distinction of a wide range of habitats in different Sanctuaries, National Parks and Tiger reserves. The habitats extend all over the State. Most of the important mammals of India are found here. Among the rare and endangered animal species are the Elephant, Tiger leopard, Wilddog, Striped hyena, Jungle Cats, Jackals, Indian Pengolin, Slender Lories, Lion tailed macaque, Sloth bear, Bison or gaur, Black buck, Nilgiris tatur, Grizzled giant squirrel, dugong and mouse deer.

Tamil Nadu has also the unique distinction of having two biospheres one in the Nilgiris, and another in Gulf of Mannar. A Tiger reserve under “Project Tiger” has been established combining Mundanthurai and Kalakadu sanctuaries.