They both hail from Scotland, are similar in type and originally were bred for vermin hunting. The primary difference between Westies -- West Highland white terriers -- and Scotties, or Scottish terriers, is that the former is always white, while the latter is never that shade.
The Westie's ancestors originally appeared in various colors. The Westie was developed when a landowner accidentally shot one of his reddish cairn terriers, thinking the dog was a fox. No one would mistake a pure white canine for a vulpine, so that landowner and breed founder Col. Edward Donald Malcolm began the breeding of white terriers in the 19th century.
The Scottie's heritage is ancient, dating prior to the Roman invasion of Britain. He is the founder of the small terrier breeds of Great Britain, including the Westie.
At maturity, the male Westie stands 11 inches tall at the shoulder, with female Westies 1 inch shorter. Male and female Scottish terriers both reach 10 inches in height. The adult Westie weighs between 13 to 22 pounds, while the Scottie weighs between 18 and 22 pounds.
Coat and Colors
Westies sport a white double coat, with the topcoat consisting of hard, straight hairs. While light wheaten coloring occasionally shows up in the breed, these dogs cannot be shown in AKC conformation classes.
The Scottie boasts a broken coat, with a wiry topcoat above a soft undercoat. Besides black, Scotties also appear in wheaten or brindle, the latter a wheaten base coat with black striping.
If you have children, the Westie probably makes the better choice. He's generally a happier dog than the serious Scottie. While both breeds have terrier-tude, the Scottie has it in spades. That doesn't mean he doesn't love his people, because he is devoted, but he doesn't have much patience for small kids. The Westie generally gets on with other dogs -- the Scottie, not so much. Both breeds are territorial and make fine watchdogs. The Westie takes to training somewhat more easily than the Scottie, but both breeds inherit a stubborn streak.
Both breeds are active, and naturally love to dig and pursue small animals. That includes felines. If you share your life with cats, the Westie is more likely to tolerate them than the Scottie.