My 14 month old has stared biting from around 11 months. It really really hurts I tell her no firmly and stop her I move true shaking my head holding my finger up, moving her away and putting her in the travel cot for a few minutes after but she still does it I'm really worried she's going to bite at nursery she has tried a couple of times with staff but thankfully has not tried to bite any other babies. If I say no she smiles and does it again. In all other respects she's a happy well behaved and placid and very sociable