Dog Fur and Dog Hair—What's the Difference?

Is knowing whether your pet has dog hair or dog fur important to you? Many believe that determining whether a dog has fur or hair tells them whether the dog will cause allergic reactions. There are also those who take great pride in the fact that their dog has hair, not fur, claiming they don't shed and are hypoallergenic. Both of these common beliefs are really misconceptions and the differences between hair and fur are essentially little more than a matter of length and texture.

Fur and Hair Are Chemically the Same

The reality is that both fur and hair are chemically indistinguishable. They are both made up of keratin, the chemical that also creates skin and nails. Technically this means that whether a dog has hair or fur, it's not the reason they may appear to be hypoallergenic.

Hair Has a Longer Growth Cycle

One difference in determining hair from fur is the growing cycle. Hair has various growth phases and the length of the various phases helps determine if people consider the dog's coat to be fur or hair.

• Anagen is the phase of new hair growth.
• Catagen is the transition phase where hair stops growing and the outer root sheath attaches to the hair.
• Telogen is the resting phase.
• Exogen is when the hair falls out and the follicle moves back into the anagen phase. The exogen phase is typically longer during warm months as the undercoats and excess hair are used as insulation during cold weather.

Hair seems to continuously grow, having a longer anagen phase, while coats that continuously shed have shorter anagen hair growth phases and are called fur.

Fur and Hair Have Different Textures

Texture is also a key factor in distinguishing hair from fur.

• Hair tends to be longer and finer in texture, and will frequently be wavy or curly. It is this curliness that actually traps the shedding hair and dander inside the coat, giving the appearance that the coat doesn't shed and doesn't produce allergic reactions. It is this factor, along with absence of an undercoat, that gives the impression that certain breeds are allergen-free.
• Fur is typically shorter and more dense in texture, with a finer undercoat during the colder months for warmth. Because the shedding hair easily drops from the dog, it only appears that the shedding is more profuse than the finer hair coat.

The only real differences between hair and fur are the descriptions that we have applied to hair and fur that determine the type of coat a dog has. One is not more allergen-free than the other; it is the lack of loose hair and dander as well as well as other factors, that determine whether a person is allergic or not.