Seasonal Changes in Hair Growth

Hair follicles are under hormonal regulation due to the importance of coordinating altera­tions in insulative and colour properties of a mammal’s coat to the environment or visibility to changes in sexual development. Seasonal changes usually occur twice a year in temperate regions with coordinated waves of growth and moulting to produce a thicker, warmer winter coat and shorter summer pelage. These are linked to day-length, and to a lesser extent to temperature, like seasonal breeding activity [7,103]; nutrient availability can also affect hair type because of the high metabolic requirements of hair production [104].