Types of Dog Hair and Coat
Dogs have two types of hair in their coats. There are short fluffy hairs usually called secondary hairs or the under coat. Then there is the second type of hair that is the longer and stiffer outer hairs called primary hairs that are also referred to as guard hairs, or the outer coat. Ouralso have a third type of hair which is the whisker. Whiskers are called tactile hairs because they help the dog sense his surroundings. In general terms, all have the shorter secondary hairs and longer primary hairs, however the ratio differs by age and breed. Newborn puppies lack primary hairs and this is why their coats are short and soft. Usually by six months of age most puppies have developed a good growth of primary hairs so their hair coats are longer and coarser. Even within specific dog breeds there exists many variations as to the exact length, color, and texture of the hair coat. These coat differences are largely the result of the ratio of primary to secondary hairs and the texture of these individual hairs. Each hair grows from a simple opening within the skin called a hair follicle and a puppy is born with all of the hair follicles it will ever possess. All future differences or changes of the hair coat will be due to changes within the follicle. Each hair shaft produced by a hair follicle will eventually die and be removed (shed) and replaced by a new hair shaft produced by that hair follicle. All of every breed continually shed old dead hair from the follicle and replace it with a new live and growing hair. There is no such thing as a non- dog breed. The rate at which an individual sheds is, however, governed by such factors as age, amount of sunlight, outside temperature, hormones, allergies, nutrition, breed, sex, etc. Indoor , because of artificial heat and more importantly light, tend to shed in a more or less continuous fashion. Dogs kept outside tend to shed for several weeks during major seasonal changes, most notably in spring and fall. Usually they grow more secondary hairs or down in the fall for warmth. In the spring they lose the down and replace much of it with the longer guard hairs.