I don't know -- I've known that forever. Had a lot of cats. A lot of cats. Calicos are my fave -- so I guess I know more about them than any other kind. Calico cats are not very common -- you're lucky to have one! All of mine have been sweethearts, too -- don't know if that's a trait. BTW -- Calicos come in pastel (grey, peach, white) and regular (black, orange, white). They also come in long-hair and short. They are ALL beautifiul.
Do you have a picture of yours?