It's not known how long the baby lay buried under ground and doctors say they can only guess how she survived. Dr Khanna said she might have been buried as long as "three to four days, surviving on her brown fat". Babies are born with fat on their abdomen, thigh and cheek and they can survive on it in an emergency for some time. But other experts give a more conservative estimate - they say she could have been only buried for "two to three hours" and might have survived for "another hour or two" if she hadn't been rescued.