Some dog breeds have two coats of fur, or what is more commonly called a double coat. The bottom layer is dense and soft, while the outer layer is coarse and long. Together, the two layers serve to insulate the dog against cold and heat as well as to give some bruise and abrasion protection. Dogs who originated from working breeds or those who originated in very cold climates are likely to have double coats.
Among breeds of the herding or working class are the Australian shepherd, the Beauceron, the Belgian sheepdog, the briard, the border collie, the Bouvier des Flandres, the German shepherd, the Old English sheepdog and the rough collie. These dogs were bred to work long hours in all types of weather, hence the protective double coats. In heavy rain, water rolls off the coarse, longer hair of their outer coats rather than seeps into their inner coat. The density of the inner coats helps to keep them warmer than dogs with one coat of hair, such as poodles.
Spitz dogs descended from what is now called the Finnish spitz. The spitz were recognized by the Kennel Club in England in 1870. The Finnish spitz has a double coat, because it was originally bred to live outdoors all winter, pulling sleds. Other types of spitz dogs, all of which have double coats, include the Akita, the Alaskan husky, the Alaskan malamute, the American Eskimo dog, the Finnish Lapphund, the German spitz, the keeshond, the Korean Jindo, the Norweigian elkhound, the Pomeranian, the Samoyed, the Shiba Inu, and the Siberian husky.
Mastiff dogs are large, muscular dogs in the working group; they historically worked guarding livestock and other property but not herding. Mastiff dog breeds with double coats include the Bernese mountain dog,the Great Pyrenees, the Leonberger, the Newfoundland, the St. Bernard, and the Tibetan mastiff.
Dogs in the terrier group are small and feisty, and they're excellent hunters of vermin. Some terrier breeds have double coats. Those that do tend to have a wiry outer coat. Terriers with double coats include the Australian terrier, the cairn terrier, the Irish terrier, the miniature schnauzer, the Norfolk terrier, the Sealyham terrier, the Scottish terrier, the wheaten terrier, the wirehaired fox terrier and the Yorkshire terrier.
Maintaining a Healthy Coat
Dogs with double coats tend to shed heavily twice a year; however, they shed throughout the year, moreso if you don't regularly and properly groom. Frequent brushing, at least twice a week but ideally every day, will remove dead hair and minimize loose shedding. Bathing will loosen dead hair and make it easier for you to brush it out. Always brush your dog's coat before you bathe him to help prevent the hair from matting. Matted hair and knots pull on your dog's skin; it can be extremely painful.