Stop the Red Hair remarks it logical to assume that today all surviving Uzumaki have different color hairs sines many of them have married non Uzumaki. Red hair was common when they lived in Uzu. Look at Jewish people originally you could not tell a Jew from an Arab in Jesus time but with the destruction of the temple in 70 AD. Jews were exiled to the 4 conners of the Roman Empire and their were not always fellow Jews to married so many Jews married Jewish converts who were German,Slavic,RomanCelt and so on adding Blond,red heads, Green and Blue eyed genes to the Jewish people. The same for the Uzumaki.