Are Cara Cara navel oranges part grapefruit?

Cara Cara navel oranges may appear similar to Ruby red grapefruit, but other than color and being citrus fruits, they are not the same. Cara Cara navel oranges are a result of a mutation in the navel orange which was found in Venezuela. Cara Cara navel oranges are sweet and their beautiful coloring comes from lycopene and beta-carotene.