I think that "smutty" nose is more common than not on black and white parti to one extent or another. But not all Nauti Havanese have it either... Boodles doesn't, nor does Astro's sister, QT:
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OTOH, my puppy, "Jelly Bean", (who became Boo), had SO much black surrounding his nose that it became like a very striking "double mustache"!
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These pictures are too cute for words! ❤