Pet shedding is often explained as "a natural process", or "the consequence of evolution". Very little information was found on how pets shed, so I decided to dig a little deeper. To my surprise, there was extensive information on the growth cycle of human hair, but the hair cycles of other mammals still contained many mysteries.
Let me begin by saying that I am not an expert, a scientist or a veterinarian. I am a curious mind that wanted answers around how to combat the issue of pet shedding, so I embarked on a research project . My interpretation of these findings is for information purposes only but I offer links back to my sources so you can come to your own conclusions. I used this information in combination with surveying, prototyping and testing to create my first pet grooming product. I found this information so fascinating that I wanted to share my findings.
The Mammal Hair Cycle
The hair cycle of most mammals go through similar stages. The Sage Journal has an excellent article by Welle and Wiener in which they explain these processes in great scientific detail. The basics of the hair cycle is explained as having three distinct phases:
In the Growth Phase the hair germ begins to grow the follicle, which continues until the next stage is signaled to begin. This next stage is the Regression Phase, where the hair germ recedes, detaches from the follicle and hair growth stops. When this phase is completed, the hair goes into a Dormant Phase. In this phase the hair sits in the pore and is eventually pushed out when a new growth stage begins.
While mammals share these similar stages, the difference in growth cycles occurs in the length of each stage. In Welle and Wiener's research they found information from Duverger and Morasso that discussed the phase lengths as it pertains to humans. For human scalp hair, the growth phase lasts 2 to 6 years, the regression phase 2 to 3 weeks and the dormant phase about 3 months. This hair cycle is similar to sheep and certain dog breeds (think dogs that need hair cuts such as poodles or bichon frises).
The length of these stages in shedding mammals is where the scientific research starts to show gaps. In shedding breeds, hair grows to an average predictable length, and it is at this length the hair follicle moves into its dormant phase. How long the hair remains in this dormant stage is mostly unknown, but this is the stage where the majority of hair will be in at any given time. The hair our pets shed each day are the ones that have moved from this dormant stage into a new growth stage.
Hair Density and Its Impact
What can seem like an excessive amount of shedding in our pets can be attributed to not just the hair cycle, but also to the density of hair in companion animals. According to an excellent article by Moriello (another suggested read) in the Merck Veterinary Manual, dog hair follicles are compound, in which there is a central hair surrounded by 3-15 smaller hairs coming out of the same pore. The central hair is what we see on a pets beautiful top coat and the smaller hairs constitute the undercoat. These hairs can adapt to be thicker or finer depending on environmental conditions. This suggests that mammals with faster hair cycles would be more capable at adapting to their environment and more likely to survive through temperature fluctuations. This would explain how shedding was a necessary part of evolution.
In the publication Hair Loss Disorders in Domestic Animals by Macklenburg et al, hair
density is discussed as being 1500-4000 hairs/cm2 in dogs and 6000-10000 hairs/cm2 in cats. Compare this to human hair density of 20-35 hairs/cm2. You can see by these measurements why pets have the ability to shed so much without going bald.
Conclusions on Pet Shedding
It seems that in order to combat pet shedding, we should work with nature, rather than against it. There is no reason to use a grooming product that rips or cuts out a hair follicle that is not on the verge of falling out as a new growth cycle is beginning. How to target this hair is the basis for the grooming tool I created.
If you feel your pet's shedding goes beyond this natural process you should always check with your vet.
I hope you enjoyed this quick summary of the information I found during my research. Please consider subscribing to my mail list here where I will give updates on the timing of the release of my first grooming tool.