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Why Do Mammals Have Hair?

One of the distinguishing features of a mammal is that they have hair. I wanted to find out why mammals have hair and if all mammals have hair.

All mammals have hair, including marine mammals such as whales and dolphins. Hair (or fur) is one of the characteristics that define a mammal. The fur is used to insulate against the cold, but whiskers are used as sensory organs, especially in nocturnal animals.

Having hair is one of the characteristics of a mammal. Although some mammals may not have much hair, they do always have some. If you want some more information, then please read on.

Why Do Mammals Have Hair?

An important characteristic of mammals is that they are warm-blooded; they need a high body temperature to survive.

Hair and fur trap air, creating a layer that insulates the skin on their bodies from the environment’s colder temperatures. The thicker the fur, the warmer the body will be. This is also the same for how oily the fur is. A seal, for example, which lives in cold northern waters, has a thick, oilier fur than a raccoon.

Hair is used as insulation, keeping body temperatures regulated when it is cold outside. The hair is also used to keep the sun off the body as well.

Humpback whale

It seems that some animals have more fur than others. However, this is not always the case. Chimpanzees have the same amount of hair follicles as human beings. However, as the individual hairs are longer than humans, their fur covers the entire body.

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Do All Mammals Have Hair?

Having hair is a characteristic of mammals, and all mammals do have hair. Although all mammals have hair, it is not as easily recognizable on all species, especially marine mammals. Even mammals such as the naked mole rats, known to have no fur, have whiskers and hair on their feet.

Marine mammals, such as dolphins, whales, manatees, and walruses do not have much fur, using blubber instead to keep them warm in the cold conditions. However, they do have some hair.

The quills of a porcupine are also a type of hair. Made of keratin, the quills are an outgrowth of protein from the skin. The quills on a porcupine harken back to the Mesozoic era when it is thought that feathers and hair came from the same sort of reptile-like scale.

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Are Hair and Fur the Same?

Hair and fur have the same chemical make-up and are indistinguishable. Both are made from keratin, which is a protein. Fur is generally used on non-human animals, whereas the word hair is used mainly for humans.

The fur is also known by another name, which means the same. Pelage refers to the hair on the bodies of non-human animals. Whereas human hair does not stop growing and will grow independently, the fur on animals grows to a certain length and then generally stops. This is not the same for all animals, but it is more common.

Why Do Animals Have Different Colored Fur?

Animals have different colors for a few different reasons. Some animals have evolved their fur colors and patterns to act as camouflage. Other animals use their colors to warn animals away from them or entice a mate during the mating season.

The color of the fur is due to the cells in the skin. These cells produce a skin pigment called melanin. Melanin is the pigment that gives the fur its color. The shade of color depends on the animal’s genetic make-up. Some animals carry genes for a solid color, such as a black labrador, whereas other animals, such as a bobcat, carry genes for multiple shades of colors.


Camouflage enables an animal to remain hidden from other animals while in the wild. There are two ways that an animal can camouflage itself. These are either by making them difficult for other animals to see them or by disguising themselves.

A jaguar uses its spots as a disruptive coloration to break up the outline of its shape. This also helps them to conceal body parts, making them harder to see by their prey. The spots are called rosettes, which help them in the forests they inhabit.

A snowshoe hare camouflages itself by changing its color to its surroundings. The white fur blends into the snow, which makes up their habitat in the winter. Snowshoe hares adapt to the weather and can change their fur color depending on the season.

During spring and summer, the snowshoe hare is a reddish-brown color, which helps them camouflage in with their surroundings of dirt and rocks. In the winter, snowshoe hares change their fur color to white. This helps them blend in with the snow on the ground.

In the spring and summer, the darker fur has more pigmentation, but less melanin is activated in the fur in winter. This is due to a reaction to less exposure to light.

With shorter days and longer nights in the winter, this causes the change to white. Rabbits and hares molt several times a year. The fur grows back a different color, helping them to camouflage from predators in different seasons.

What is Hair Made From?

The hair or fur on a mammal is all made from the same substance. Hair is made from a hard protein called keratin. Amino acids and molecules form the protein. Mammals intake the amino acids from the protein in their diet. If they do not eat enough protein, then this will not support healthy hair growth.

Single hairs are made up of a hair shaft and a hair follicle. The follicle can be found below the skin and is where the new growth occurs. The bulb (base of the follicle) contains cells that produce the shaft of the hair.

Hair Diagram

The bulb is connected to a grid of blood vessels within the scalp, which passes nutrients to the bulb. To keep the hair moisturized, the follicle produces oil, called sebum, from a sebaceous gland.

There are several nutrients that hair needs to grow strong and long. Without these, the hair would be brittle and short.


Biotin is a form of vitamin B. It is water-soluble and is also known as vitamin B7, or vitamin H. Biotin is essential for hair growth as it metabolizes the amino acids from food.

As the amino acids make up the protein building blocks, they help to form the keratin in the hair. Biotin also helps to improve the resiliency and strength of the fur to stop environmental damage.


Red blood cells deliver nutrients and oxygen to hair follicles, and iron helps to form these cells. If a mammal loses its hair, it is generally due to a deficiency of iron in the diet.


Niacin, also known as vitamin B3, helps repair DNA. The DNA in the hair follicles passes messages to the cells in the follicles. These messages are necessary for healthy hair growth.

Structure of the hair bulb

Vitamin C

Vitamin C is also essential in producing red blood cells to help with hair growth. Vitamin C helps the body absorb the iron, allowing the delivery of oxygen to the hair follicles. Vitamin C also works as an antioxidant, protecting the hair follicles from hair loss and discoloration.


Whereas Niacin helps to repair DNA, Zinc supports the production of DNA. This production of DNA divides the cells and is essential for hair growth. Zinc is also a contributory factor in balancing hormones. Unbalanced hormones can cause hair loss, and without enough zinc, the hair follicle structure can break down, leading to shedding.

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