Guard hairs are the longest, thickest hairs in a mammal's coat. They taper to a point and protect the undercoat from the elements. They are often waterproof and stick out above the rest of the coat.
A dog'sfur usually consists of longer, stiffer, guard hairs—which can be straight, wiry, or wavy, and of various lengths, hiding a soft, short-haired undercoat.
Fur comes from the coats of animals; the animal's coat may consist of short ground hair, long guardhair, and, in some cases, medium awn hair.
Ground hair or underfur — the bottom layer consisting of wool hairs which tend to be shorter, flattened, curly and denser than the top layer.