Board Thread:Theories and Speculation/@comment-45861757-20200522075225/@comment-4974066-20200522170517

I think it's possible that the whisker marks are a leftover design from the original naruto from the pilot, where naruto himself was the nine-tails. The whiskers were probably always intended to be associated with the nine-tails, Keep in mind that the Ginkaku and Kinkaku also have them. If naruto didnt have the nine-tails as an adult, I'd wager Himawari and Boruto wouldn't have them. But as for lore reasons, I'd go with Ultima's idea.