For most hair, there comes a time when it will naturally fall out. I am not talking about male pattern baldness; I am talking about shedding. In the case of most furs, the fibers reach a certain length and naturally fall out. Shedding can also be triggered by season, temperature, poor nutrition, pregnancy hormones, stress and/or illness.
In the case of hair, the individual fibers will continue to grow and will intermittently shed. Most humans have around 500 follicles per square inch on their heads; however, only 150-200 of the follicles are active at any given time. This is why your hair keeps growing, but you still need to clean your hairbrush. Shedding can be caused by damage to the follicle, whether by the use of certain chemicals, aggressive brushing or exposure to sun. Often, the damaged hair doesn’t shed until the follicle becomes active, up to four months after the damage occurs.
 Shrek, the celebrity Merino sheep, evaded being sheared for six years by hiding “outlaw-style” in caves in New Zealand. When he was recaptured and finally given a trim, his fleece weighed a whopping 27kg (60lbs)! The average Merino fleece sheared once per year weighs 12-16lbs. |
Most modern sheep breeds continually grow fiber and do not naturally shed, however, there are exceptions to this rule. Primitive breeds are those breeds that existed before humans began to meddle with them and they have changed minimally since their discovery. Examples of primitive breeds include Jacob, Gotland, Shetland and Navajo-Churro.
These breeds are unique in that they maintain some of the hair-like qualities that benefited their pre-domesticated forefathers. These breeds lose their hair in a process called “rueing”. During the Spring, these breeds have a natural break in their fleece, similar to the way that fur sheds when it reaches a certain length. For some sheep, they will rue their whole fleece while others may only shed the fiber around their necks and upper backs. Genetics plays a role in how a sheep rues its fleece.
Asia-Pacific | NZ’s famous sheep gets TV haircut. (2004, April 28). Retrieved September 17, 2017, from http://news.bbc.co.uk/2/hi/asia-pacific/3665735.stm