There is a wide range of herbivores, carnivores and omnivores in the Grizzled Squirrel Sanctuary. Resident and migrating elephants are common. The other important animals are Tiger, Leopard, Gaur, Nilgiri tahr, Spotted deer, Barking deer, Sambar, Wild-boar, Porcupine, Nilgiri langur, Lion-tailed macaque, Common langur, Slender lorris, Bonnet macaque, Sloth bear, Indian Giant Squirrel and Flying Squirrel.
The sanctuary is inhabited by extremely rich and diverse fauna. Over 200 species of avifauna have been reported from this sanctuary that includes some rare birds such as the Red faced Malkoha, Nilgiri Flycatcher and Malayan Night Heron. The Great Pied Hornbill is well and widely distributed in the Sanctuary The main raptors are the Serpent Eagle, Hawks and Black Eagle. The Sanctuary has 18 species of snakes, 15 species of lizards, over 10 species of amphibians and over 56 species of butterflies now.
The Grizzled Squirrel (Ratufa macroura) –flagship species of this sanctuary is highly restricted to south India and Sri Lanka. Ratufa macroura dandolena is distinctive in having the dorsal surface and tail grey or brownish grey more or less grizzled with white. It breeds once a year, producing a single offspring. The distribution of the Grizzled Squirrels is restricted to seven isolated riparian dry deciduous forests in the Sanctuary.
As soon as day light appears in the morning the animal comes out of the nest., reaches the food trees and starts feeding. From 6 AM to 11 AM “Feeding” is its most dominant activity. In the evening, 3 to 4 PM is the major feeding time. The squirrels take rest between 11 AM and 3 PM at the stretch.
The squirrels feed mostly on fruits. When they perceive lack of fruits, they go in for tender leaves. Seeds, tender leaves and fruits are their diet. Tamarind forms the key food tree species in Alagarkoil area, but the squirrels survive also in localities where there are no Tamarind trees.The important food trees are Tamarind, Vagai, Usil, Naval, Neer maruthu, Thani, Neem and Mango
The home range of an individual is between 0.197 ha. And 0.611 ha. This species is restricted to mixed deciduous forests and riverine forests occurring in plains or at elevations below 800 m MSL.
Drey construction and visit to drey
The drey’s location is mostly at forked branches where crowns of neighbouring trees interlink. This would enable the squirrel to move away from the site by jumping from tree to tree when threatened. It is observed that an individual constructs two nests within its home range. The squirrels occasionally visit their nests during day time.