A baby squirrel will make the transition to solid food from weeks 6-12 of its age. So, initially you need to keep them on proper diet. Baby squirrels are called infants while in the nest. Then for their first year they're usually referred to as Juveniles. After the first year, they become adults and are simply called squirrels. Baby squirrels can be called kittens or kits, pups, or just babies depending on who you ask. Baby squirells have no official name but baby squirells with the various breeds of african pygmy to alpine marmot to red and grey squirrels, they are all lovable rodents.