Biting down hard with gums

This will probably sound like a really stupid question but hope someone can answer me.

When I put my finger into my 4.5 month olds mouth today (well he actually pulled my finger in) I noticed that he was biting my finger with his gums and applying quite a bit of pressure. Is this just a normal developmental thing that he would be doing or is it a sign of teeth starting to come through. I can see his teeth through the front of his gums (little white patches) but can't see or feel anything on the top of the gum. His fingers/fists have been a permanent fixture in his mouth for the last few weeks and he also sucks on his wrap, comforter and anything else material you give him which I had just put down to normal " put everything into your mouth" behaviour. Now however he has taken to pulling my fingers into his mouth also.

Is anything exciting happening here or just normal behaviour?

sounds normal to me! my DS whose 12 months still does that! his fav. thing to munch on his the terry flats we use over our shoulders. he also like munching on fingers - and of late feet as well, which is cute, but he's now got 4 teeth and it hurts lol.

All very normal hon and not necessarily a sign of teething. Babies use their mouth to explore so everything they get hold of tends to go in the mouth. Their little bite is surprisingly fierce, hey?!