Parambikulam is open throughout the year, but is best avoided during the monsoon.
The Parambikulam Wildlife Sanctuary located between the branches of the Periyar river is essentially a bird sanctuary.
Thickly forested with stands of bamboo, sandalwood, rosewood and teak, the sanctuary has some marshy land and scattered patches of grassland. Parambikulam was once home to some of south India's finest stands of teak. Little remains of the original teak forests, other than the famous Kannimari teak tree, the largest in Asia as most of these have now been replaced by teak plantations.
Parambikulam has one of the largest population of gaur (bison). It is also a home to elephants, sloth bears, wild boars, sambhars, chital tigers, panthers and crocodiles. There are also bonnet macaques, spectacled cobras, kraits, vipers, turtles, darters, little cormorants and black eagles.