Forty one species of mammals are reported in the area, which include 6 Western Ghats endemics. Of the 179 species of birds, 10 are endemics, 6 range restricted and 5 globally threatened species. Thirteen of these are listed in the schedule I of the Indian Wildlife Protection Act (1972). Preliminary surveys indicate the presence of 36 species of reptiles including 8 Western Ghats endemics. This forested habitat is known to be an ideal haunt for King Cobra, the largest venomous snake in the world.

Thirty eight species of amphibians are known from this area of which 26 are Western Ghats endemics. The amphibians include the recently discovered Philautus ponmudi, P. anili, P. tuberohumerus, P. neurostegona, P. ochlandrae, P. akroparallagi and P. chromasynhysi . The type locality for P. ochlandrae is the reed brakes of Kakkayam dam site, the only known site for this species.

The streams of Kakkayam support 52 species of fishes including 21 Western Ghats endemics. The hill stream habitats of Kakkayam are also known for the endangered Mahseer, Tor khudree. A total of 143 species of butterflies including 8 Western Ghats endemics are known from this area. Fifty one species of Dragon flies which include 11 species of Western endemics are reported from the region.
The table shown below the level of endemism in sanctuary area:

Faunal endemism in sanctuary area