Here's a breakdown:
* Melanin: This is a pigment that gives color to skin, hair, and eyes.
* Nose Pigment: Dogs with more melanin in their nose skin have darker noses, often black.
* Genetics: The amount of melanin a dog produces is determined by their genetics.
So, while there's no "black nose bone," it's the pigment in the skin of the nose that creates the dark color.