Some animals, such as seals and sea otters, have coats with two layers of dense fur — a thick undercoat and a covering layer
of longer guard hairs.
Dogs have three types of hair: soft downy undercoat that is especially abundant in northern breeds but exists in most breeds that developed in cool or cold climates; stiffer and
often longer guard hairs that form a protective layer to protect undercoat and skin from harsh weather and cold water; and whiskers, those specialized hairs that grow in clumps on the face.
The undercoat in both varieties is short and soft while the outer coat is made
of long guard hairs.
The coat of the Belgian tervuren is a weather resistant double coat
with long guard hairs and a thick undercoat.
Undercoat hairs might get stuck in
the long guard hairs of a dog's overcoat, so you don't see shed hair around the house, but the coat is still shedding.
The former having a denser and fuller coat, and the latter having less undercoat but
longer guard hairs and generally more banks of ticking.
The long guard hairs form the outer layer and protect against snow or ice and even shed water.
What happens is that the coat's soft layer sheds off and is replaced by a coat that has a dense, double, thick inner layer along with an outer layer of
long guard hairs.
The long guard hairs are rough and feel harsh to the touch.
Guinea pigs have
long guard hairs with a short undercoat.
Jack Russell Terriers can have any of three coat types: rough, a double coat with a short dense undercoat and a dense wiry outer coat with wiry eyebrows and a beard; broken, which is a coat between rough and smooth, closer than a rough coat with
longer guard hairs than in a smooth, with or without the eyebrows and beard; and smooth, with a short, flat, hard coat.
The Alaskan Klee Kai has a double coat; an undercoat that is short and soft and an outer coat that is made of
longer guard hairs.
Also consider that much of what is shaved will be
the longer guard hairs, exposing the softer, shorter undercoat.