Dogs come in many shapes and sizes. The smallest breeds include the toy and miniature varieties, such as the Toy Poodle, Papillon, Chihuahua, and Shih Tzu. These dogs usually weigh only 5 to 10 pounds (2.3 to 4.5 kilograms), or even less. Medium-sized dogs include many of the terriers and spaniels, which weigh in the 10 to 50 pound (4.5 to 23 kilograms) range. Larger still are the retrievers, shepherds, and setters, which often weigh 65 to 100 pounds (30 to 45 kilograms). Finally, the giant breeds, such as the Mastiff, Komondor, and Saint... read full review »