Hair is mainly made up of keratin. It is the same material that a cat’s claws are made of. Keratin is a protein. Because hair is made up of protein, hair growth uses up a good percentage of a cat’s protein intake. A cat’s coat is made up of guard hairs, bristle or awn hairs, down hairs (wool hairs) and whiskers.
If you stroke a cat from root to tip, it feels smooth, whereas stroking from tip to root feels rough. This is because of the way the cells of the hair strands lie. The surface of hair strands consists of overlapping cuticle sells. These point away from the body. As we stroke down the back of the cat this is from root to tip.
A cat’s hair grows in cycles. The cycles are controlled by hormones, the surrounding temperature and the length of daylight hours.
A cat’s hair grows to a predetermined length. The length is dictated by the cat’s genes. The hair grows during a 60 to 90 day growth period. There is then a short transitional stage. Thereafter there is a resting stage of 40 to 60 days when it falls out allowing new hair to grow. Shedding of hair is gradual because individual hairs are at different stages at any one time.
The main determining factor for hair growth is light. An increase in light stimulates a spring moult. For indoor cats, shedding often takes place year-round. We know that there is no such thing as a non-shedding cat breed.
Different coats have evolved to accommodate cats living in different climates. Evolution has provided the cat with an excellent defence against heat and cold. We know that some breeds have adapted to northern climates. These are, for example, the British Shorthair, Maine Coon and The Norwegian Forest Cat. They are endowed with dense coats with insulating down. In cold weather their hair stands erect. This allows air to be trapped within the coat providing installation in a similar way to double glazed windows. Fleece jackets for people work on the same principle.
In addition, a layer of fat under the skin insulates the body as heat is lost through fat at one third of the rate as through muscle. In very cold conditions a cat will curl up creating a greater mass to retain heat and cover his face with his tail to protect it from freezing air.
Conversely, some breeds are adapted to hot climates. They radiate heat from their bodies more efficiently to lose it. The Siamese cat does not have down hair. The cat has a single coat. Cats which have this insulating layer of fur shed it in hot climates. If there are still warm they shed primary hairs. In addition, blood vessels in the skin dilate which speeds up the loss of heat from the body.
We know that cats do not sweat. Sweat takes heat away from the body through the latent heat of evaporation. Cats achieve the same effect by licking their fur. The saliva deposited on their fur evaporates carrying heat away from the body.
Despite the excellent defences against hot and cold, the domestic cat can still suffer from frostbite and heat prostration. A cat can die quite quickly if trapped inside a hot car on a sunny day. A cat’s ears and his paws are prone to frostbite. On freezing wet days a cat can suffer from hypothermia because his fur loses its insulating capacity.
A cat’s whiskers are hair specialised for sensation. There are called vibrissae (tactile hairs). Are cats supposed to lose whiskers? Ans: Yes. There are other individual hair strands scattered over the skin and surrounded by a web of blood vessels and nerves which act like short whiskers. These are called tylotrichs.
In rexed cats, the growth of hair is retarded by the genes carried by the cat. For example, the Cornish Rex has no guard hairs. The Devon Rex has soft guard hairs which are almost identical to down hairs.
The current world’s hairiest feline is Colonel Meow.
