Why do hair follicles cycle?
Cycling is a unique feature of the hair follicle, no other structure in an adult mammal cycles in such a way. A single answer is not possible, but a number of reasons have been cited by biologists. Foremost among them is that skin molting is an integral characteristic of all organisms. Hair being an appendage of the skin is also shed periodically. Animals shed their fur to adapt to seasonal changes and during the mating season. Fur is also shed to cleanse their body surface, protect from improper formation of follicle or to protect from malignant degeneration, which might occur due to rapid cell degeneration. Although this explains the hair follicle cycle in animals, it does not explain the cycling of individual follicles in other mammals. Even in rodents and other animals that display synchronized cycling of follicles, the cycle becomes heterogeneous as the animals age, and there are also individual waves of hair follicle cycling traveling through the skins of these animals. An argume
