Hedgies can bite for a number of different reasons.
A few thoughts off the top of my head are:
- you have an unfamiliar (you are new to your baby) or strong scent (either something yummy so hedgie thinks you are food or something he does not like/is scary)
- your baby is scared
- your baby has learned that if he bites, you'll have a certain reaction (like putting him back in his cage) and he likes that reaction
So you can do things like making sure you wash with the same unscented soap each time before you pick him up. Pick him up differently (sing to him before picking him up, give him more time to get used to you). React differently upon being bitten (hold him in a fleece blanket instead of setting him back down).
But, really, your solution will depend more on what's going on for you and your hedgie. How old is your baby and how long have you had him? Under what circumstances does he bite?
