The silent Valley National Park is home to a fragile and unique tropical evergreen rain forest. The Silent Valley National Park covers an area of about 90 sq km. The Silent Valley National Park is the heart of the Nilgiri Biosphere Reserve. The Silent Valley (the clamor of Cicadas is conspicuously absent here) is abuzz with the sounds of swarming wildlife. The most important inhabitants of this national Park include rare birds, tiger and deer. Besides these animals, there are numerous other species of wildlife like butterflies, moths, Great Indian Hornbill; Lion tailed Macaque and the Nilgiri Laughing thrush. The river Kunthi descends from the Nilgiri hills and traverses the full length of the valley and sprints down to the plains through these forests. The water of River Kunthi is crystal clear throughout the year.