Haydies, it's mostly a play thing, and taking an interest in everything.

WRT to the iron stores, they run out at sometime between 6 and 12 months. Mostly bf babies need iron much later than ff bubs, as the iron in bm is more readily absorbed than the iron from any other source. BM alone will give babies all the iron they need for 12 months in most cases. The baby cereal products that you buy all have added iron, but the iron in that form is not easily absorbed, so in actual fact babies get less iron from those foods than from bm. Often when you introduce solids too early, the food replaces some milk, so the baby gets less iron than when they were just bfing. HTH.