Many dog breeds have a double coat, a soft fine layer of fur underneath a courser layer of longer hairs. The dense soft undercoat will help to insulate the dog against cold and heat and the longer course hairs will protect against other elements including water and snow.
Example breeds: Husky, Retriever, Spitz, Terrier, Sheepdog
This coat type can be quite difficult to manage at home and will invariably require some routine clipping and trimming to maintain the coat and reduce mats and tangles. The coat will require brushing every day to remove loose hair and dirt.
Example breeds: Bichon Frise, Curly Coated Retriever, American Water Spaniel and Poodle.