Many states have laws against possessing native squirrels. So, if you find a baby, you must try to locate a wildlife rehabilitator soon. Till you are able to locate a wildlife rehabilitator, you should keep the baby warm and hydrated. Normally, the mother nurses the baby for 2-3 months and teaches it basic skills that would be required for survival, but if the baby gets separated, the mother might come looking for the baby. Though she might not be bothered by the human smell, she might not take back a cold and dehydrated baby. So, do keep the baby warm.