This squirrel is very common here, Plantain Squirrels eat mainly fruits and nuts but also eat on insects, butterfly larvae (here I posted on 19/04/08) and other food that they come across including birds eggs.
Like birds, they are active in the morning and evening.
Update: The actual ID of this squirrel is: Horse-tailed Squirrel (Sundasciurus hippurus) Look at that tail - thick and bushy, dark contrast with body fur.