Gray is considered one of the standard colorations of the Cairn terrier as per the AKC breed standards. The D-locus gene is responsible for the grayish color in these dogs. Most of them start as black, and as they grow, the color dilutes to a light gray shade. The variation of gray, i.e., gray brindle, is also a recognized coat color. The gray brindle dogs have a blend of black and gray with black markings on their face.
