Both my babies, Larkin and Sera, have double crowns! (A crown is a circle or "whirl" of hair). Being a Rhodesian Ridgeback, it is expected that Sera would have a double crown. That is what gives her the "ridge" along her back, where the hair runs the opposite direction (from back to front instead of front to back), and it is the primary distinctive feature on a Rhodesian Ridgeback.
Funny enough, Larkin also has a double crown! While most people have one crown (and thus, one part in their hairline), Larkin has two, which is fairly rare. It is responsible for her current faux-hawk hairstyle as the hair from her two parts comes together in the middle! Having a double crown is supposedly lucky and our pediatrician has told us that it means that Larkin will likely be ambidextrous! The theory is this: right-handed people have hair that grows clockwise from the crown, left-handed people have counterclockwise hair growth from the crown, and people that are ambidextrous have double crowns (one growing in each direction).