Dogs come in all shapes and sizes, but as any puppy aficionado knows, they are always cute—no matter how big or small—even when a dog tall enough to drink from the kitchen sink thinks he's a lapdog.

Having originated in the Pyrenees Mountains as far back as the 15th century, Great Pyrenees were bred as flock guardians. Their large size ensured they were a formidable presence which, coupled with ...