The Great Pyrenees is a large, powerful dog with a dense, weather-resistant double coat, mainly white and sometimes marked with grey, badger, reddish brown or tan on the head, ears and base of the tail. The coat thickens into a mane at the neck, and the tail is long and plumed. Double dewclaws on the hind legs are a required feature of the standard. Calm and patient with its own household, it is also independent, watchful and reserved with strangers, and known for barking at night.
The Great Pyrenees, known in Britain as the Pyrenean Mountain Dog and in France often called the patou, comes from the mountains along the French–Spanish border. As wolves and bears grew scarce, working numbers dwindled, and the modern breed owes much to French enthusiasts who sought out surviving mountain dogs in the early twentieth century. It was bred to live among the flock and drive off predators rather than to herd. It often worked alongside the smaller Pyrenean Shepherd, which did the herding. It has taken up that work again in parts of France since wolves returned to the Alps, and has also guarded sheep against coyotes in North America.