The general appearance of the Sheltie is that of a miniature Rough Collie. They are a small, double coated, working dog, agile and sturdy. Blue merle Shelties may have blue eyes or one brown and one blue eye, but all others have dark-colored eyes. Their expression should be that of alertness with a gentle and sometimes reserved nature. They are often very good with children. They carry their tail down low, only lifted when alert and never carried over the back. They are an intensely loyal breed, sometimes reserved with strangers but should not be shy or showing timidness as per the AKC breed standard. Sable – Sable is dominant over other colors. May be pure for sable (two sable genes) or may be tri-factored or bi-factored (carrying one sable gene and one tricolor or bicolor gene). 'Tri-factored' sable and 'shaded' sable are not interchangeable terms. A shaded dog (one with a lot of black overlay on a sable coat) may or may not be tri-factored or bi-factored.