The other day, my best friend was talking about his kid getting braces as his teeth are slightly crowded. This made me wonder a few things about tooth development: 1. Your adult teeth come in at a young age, obviously way before your skull / jaw stop growing, so how come everybody doesn't have huge gaps between their teeth? Obviously some people do have slight gaps, but I don't remember my adult teeth being all jammed into my mouth and then slowing fitting as the years went by, there has always been enough room. 2. Why do animals like dogs and monkeys etc always seem to have perfectly straight teeth naturally? What causes humans to need braces in the first place? Anyone know the answers?