Every mutation is a stat mutation and a color mutation in one. I guarantee you each time you received a new mutation number on the ancestral counter (or if you knew your stats you can tell by the change), you also got a color. You didn't notice it because it was a color that is natural to the animal in the wild - because all colors are in the mutation palette. However, If you look at the two parents and then the newly mutated baby you'll notice it will have a color that neither of the parents have.