What does the dictionary say ? "Fur: a dense coat of hair." Certainly, it is difficult to define it otherwise. However we would never say "I like your new fur cut", though we might well say "At the moment, my cat is losing its hair" ! What are the similarities and differences between various types of hair ?
It is interesting to note that certain languages hardly differentiate between different types of hair. Thus "hair" in English or "Haar" in German applies to animal fur, human body hair and hair on the head. On the other hand, French among other languages, refines to the extreme with "chevelure" for a head of hair and "pilosité" for body hair and "pelage" for animal hair or fur. Hair is a mammalian characteristic and the three types of hair have comparable structures. They are all formed from a hair follicle situated in the skin and a visible fibre. On the other hand, the size of these elements and the parts of which they are composed are variable; to give an example, the dermal papilla of the eyelash is very large.
The categories differ above all in their role and their behaviour.
Long hair on the head is specifically human, though why it occurs on the head remains a mystery. Specialists are not absolutely sure whether it is a vestige of human development similar to the manes found on certain animals. The theory that it is designed to provide thermal protection is no better established. It can however be related that Dupuytren, doctor to Napoleon and the Grande Armée, reported that at a comparable age and state of health, bald soldiers died more rapidly than their companions during the retreat from Russia.
On the other hand the thermoregulatory role of the fur is primordial in animals. It depends particularly on the core of the fibre,Intermittent or absent in man the core of animal hair is designed to protect the beast from cold or heat. Depending on the climate where the animal lives, it has a greater or lesser number of air filled alveoli which allow maintenance of almost constant temperature.
Compared with human hair, the other significant special feature of animal fur is its growing cycle. While each human hair grows independent of its neighbours, the hair follicles of animals are synchronised: the fur thus grows and falls out at the same time. This is the phenomenon of moulting, which can sometimes be spectacular as in the ermine which looses its white winter fur to put on its brown coat for the spring and summer.
As to human body hair, it does not really replace the vellus hair until puberty and is differently localised in men and women. It is thus considered as a secondary sexual characteristic. Its response to hormones is the opposite of that of the hair on the head: male hormones encourage its growth, female hormones oppose it.
If we add that the state of the hair's exterior envelope gives it its shine and softness , can you now identify which hair belongs to which?
Use the magnifier to zoom-in the pictures and fine-out : the wolf fur.