[Krystee]

Tobie's are the same way but since they don't seem to bother him and the vet has never said anything, I just figured it was normal.
I don't know how accurate this is, but I did a google search and found this on justanswer.com.

"The scrotum skin can darken as it has little fur and the skin 'tans' in dogs to a dark gray or black.
Dog skin in this area can be dark pigmented like any skin on the dog's body can. Some dogs have dark spots under their fur that are just normal pigment coloring.
If the area is sore, swollen, or one side is more enlarged than the other this could be a sign of a health issue needing your vet to check it out for treatment.
But overall its a common color for that area of skin.
Hope this helps you!"