The grizzled giant squirrel (Ratufa macroura) is a large tree squirrel in the genus Ratufa found in the highlands of the Central and Uva provinces of Sri Lanka, and in patches of riparian forest along the Kaveri River and in the hill forests of Karnataka, Tamil Nadu and Kerala states of southern India. The International Union for Conservation of Nature (IUCN) lists the species as near threatened due to habitat loss and hunting.
Grizzled giant squirrels are named for the white flecks of hair that cover their greyish-brown bodies, giving them a grizzled look.
Subspecies dandolena is dorsally brown grizzled with white. Ventrally light brownish cream. Tail frosted with white fur. Forehead and feet are black in color. Whereas ssp. melamochra, upper parts are jet black which contrast brownish cream to orange yellow ventral surface. Tail frosted with black fur. Snout of both ssp. are pinkish color.
Their vision is good, which aids them in detecting predators. Their sense of hearing is relatively poor. The call is staccato and loud with repeated shrill cackle. It is usually uttered in morning and evening. A low "churr" is also used to communicate with nearby groups.
Hands are normally pentadactylous, with four digits and a rudimentary thumb. Fingers have large broad soft pads, where the inner pad is expanded for gripping while moving through branches. Feet are also comprised with soft pads with both fore and hind limbs possessing long, sharp claws.
In India, R. macroura has been recorded from Grizzled Squirrel Wildlife Sanctuary, Theni Forest Division, Palni Hills, Chinnar Wildlife Sanctuary, Anaimalai Tiger reserve, Sirumalai, Thiruvannamalai Forest Division of the Eastern Ghats, Hosur Forest Division and Cauvery Wildlife Sanctuary. The easternmost population of Ratufa macroura dandolena was discovered in the Pakkamalai Reserve Forest in eastern Tamil Nadu.
Ratufa macroura are known to eat fruits, nuts, insects, bird eggs, and the bark of some trees. The fruit of the climber Combretum ovalifolium is an especially important food source where it occurs. Young squirrels, upon first emerging from the nest, have been observed to feed exclusively on this fruit.
Unlike its relatives, the giant squirrel balances using its two hind feet, instead of its tail.
The species is almost entirely an arboreal, very rarely coming to the ground to escape from predators, to flee from an intruder, attack males of the territory, and connecting with females.
