The Portuguese Water Dog is a breed of dog. If comparing the structure to that of a Poodle, there are significant differences between the two breeds. The Portuguese Water Dog is built of strong substantial bone; well developed, neither refined nor coarse, and a solidly built, muscular body. The Portuguese Water Dog is off-square, slightly longer than tall when measured from prosternum to rearmost point of the buttocks, and from withers to ground. Portuguese Water Dog eyes are black or various tones of brown, and their coats can be black, brown, black and white or brown and white. Portuguese Water Dogs are active and well-suited to many dog sports. As with all purebred dogs, PWDs are vulnerable to certain genetic defects. Owing to the limited gene pool for this breed, conscientious breeders carefully study pedigrees and select dogs to minimize the chance of genetic disease and improper coat. As with many other breeds, growing popularity has encouraged breeding by people not knowledgeable about the breed.