Well...on the older versions...if you missed marrying your tama via the matchmaker OR marrying via connection, your tama turns into a "senior citizen" character....known as the Oldies / Oldtimers. Also, if two old timers marry, they give birth to another "old character" which is a secret character.
On the Versions 1, 2 and 3 you get an Oldie when your tama is 10+ years.
On the V4 and V4.5 versions, you get an Oldie when your tama is 9+ years.
Female Oldie = Otokitchi
Male Oldie = Ojitchi
Female + Male Oldies = Oyajitchi
~shawdy~