Nestled in the Cardamom Hill range to the south of the Western Ghats, Periyar is one of the most talked about wildlife sanctuaries in South India. This hilly tiger reserve embraces the Periyar river, which was originally dammed in 1867 for irrigation purposes. The excess water flooded the area, forming a massive lake out of which dead tree stumps still jut out, which offer an excellent perch to Periyar's rich birdlife. 

The Periyar Lake in the center of the sanctuary is the nucleus of the Tiger Reserve. Boat travel on the reservoir is the only means of transport and provides one of the most delightful methods of viewing the elephants and avi-fauna for which the park is known. 

Periyar is home to many endangered animal species such as the Lion-tailed Macaque, Nilgiri Langur, Indian Spotted Cevrotain (the smallest of our deer), Malayan Giant Squirrel, Flying Squirrel, Slender Loris, unique flying snakes and lizards and the Dhole (Asiatic Wild Dog). The best time to visit is between October and April, especially the latter two months, when water levels are low and animals tend to spend more time near the lake. The grass too is short during this time, resulting in greater visibility. 

Periyar harbours predators like the Tiger, Leopard, Jungle Cat and scavengers like the Striped Hyena. Otters, birds, fish and snakes inhabit the aquatic lake-shore belt, while Bonnet Macaque, Nilgiri Langur, Gaur, Tahr, Mouse Deer, Sambar and Barking Deer can be found in the adjoining forests. The water edge is also dominated by groups of Wild Boar wallowing in the mud and herds of Asiatic Elephant. 

Over 230 species of birds are found in Periyar which include rare ones like White-rumped Munia, Blyth's Pipit, Blue-eared Kingfisher, Pompadour Green Pigeon, Greater Painted Snipe, Black and Orange Flycatcher, Long-billed Leaf Warbler, Sri Lanka Frogmouth and winter visitors like the Cinnamon Bittern. Birds of prey like the White-bellied Sea Eagle are a common sight around the lake. 

The typical habitat of Periyar is rolling and steep hills covered by tropical evergreen and semi evergreen forest on upper region and moist deciduous forest and marshy grasslands in the central part.