my baby rat wont eat

Question
Hi, I have a baby rat and she/he wont eat anything. I've tried feeding him rat/hamster food, tried yogurt , given him grapes and he only nibbles at them and even tried a bit of milk in a syringe.
my baby rat doesn't really look old enough to be even around two months old yet he looks about 3 -4 weeks. I have had rats before but they've been a lot bigger than the one i have just got i believe my rat was taken away from her mother way to early because i have to take his water dispenser (with the ball thing at the end) held it and he will only drink from it when i hold it. also he has a fascination with my mouth and likes to lick my lips, I've had him for 3 days now, so when he was licking my lips i put i tiny dot of yogurt and he would eat it ? what's wrong with my baby rat or is he just adjusting still? Or could he just be to young to eat on his own ?
Please help me Im in a bit of a panic!
Thanks, Samm

Answer
 Usually when you first get a rat, especially if it is a little baby, they may be too scared to eat around you.  Have you noticed any of the food missing or moved to a different place?  Rats won't starve themselves unless they are sick; he's probably eating at night when you are asleep.

 Rats start to eat on their own starting at 2 weeks, but aren't fully weaned until 4-5 weeks.  If you think your rat may be 3-4 weeks you may want to give him some human baby soy formula in a little dish and see if he will drink it.

 Use a gram scale to keep track of his weight; since he is a young baby he should be gaining a little bit of weight every day.  If you notice his weight stays the same, or he begins to lose weight, you know he is not eating and may be ill.  He may have to be seen by a veterinarian.

 If the rat/hamster food is a seed mix, switch to a block type food.  Try to find one where the first ingredient isn't corn.  These provide better nutrition than mixes where the rat can pick out what he doesn't want.

 Hopefully he is already eating, or will start soon.  Keep track of his weight and if he shows any other signs of illness or is losing or not gaining weight, take him to the vet.

 I hope that helps you out, good luck with your rat!