A very young female stray showed up at our rural home just before Thanksgiving. She was thin and hungry but obviously a pet. We never were able to find her owners. At that time she was what I would have called brownish black, and a regular domestic longhaired cat. Nine months later she looks like a different cat. She has white tuffs between her paws. Behind her ears are extremely long silver tuffs, and her hair is tipped with silver. She weighs over 9.5 pounds. I've never seen a cat change their appearance so dramatically. The vet said she may be part Maine Coon. Is the transformation common for that breed?