The amount of hair a dog or cat sheds around the house does not depend solely on brushing or the season of the year. Shedding is a biological process regulated by light cycles and, fundamentally, by genetics.
The hair follicle goes through four natural phases: growth (anagen), regression (catagen), resting (telogen), and shedding (exogen). Although changes in natural daylight during spring and autumn trigger shedding peaks to adapt the coat to the climate, living indoors with artificial lighting and climate control often turns this cycle into continuous year-round renewal.
The Genes That Determine Hair Shedding
The intensity and type of shedding are encoded in specific genetic variants depending on the species:
In dogs:
- MC5R Gene (Shedding intensity): Regulates lipid synthesis in the follicle's sebaceous glands. Certain variants in this gene can make the difference between heavy-shedding breeds (Labrador Retriever, German Shepherd) and those with moderate shedding.
- RSPO2 Gene (Furnishings or bushy mustache and eyebrows): Determines the presence of long facial and body hair as well as continuous coat growth in breeds such as the Poodle or Schnauzer. By extending the anagen phase, dead hair is trapped within the curl or coat until brushed out, significantly reducing visible shedding around the home.
- Double coat structure: The presence of a dense, woolly undercoat multiplies the volume of hair shed during seasonal transitions.
In cats:
- FGF5 Gene (Hair length): Regulates the duration of the anagen phase. In long-haired breeds, a loss of function in this gene extends hair growth. As a result, loose hairs are more likely to tangle during grooming and form hairballs (trichobezoars) in the digestive tract.
- KRT71 Gene (Coat texture and hairlessness): Variants in this gene determine the characteristic curly coat of the Devon Rex or the almost complete absence of fur in the Sphynx, reducing or eliminating hair in the surrounding environment.
Coat Types and Shedding Levels
- Double coat (Husky, German Shepherd, Golden Retriever): Very high shedding with pronounced seasonal peaks. Requires frequent deshedding and should never be shaved, as the undercoat acts as thermal insulation.
- Continuously growing coat (Poodle, Maltese, Schnauzer): Low shedding level. Dead hair does not fall out on its own, requiring daily brushing and regular grooming.
- Short, smooth coat (Doberman Pinscher, Boxer, European Shorthair Cat): Moderate and steady shedding throughout the year. Easily managed with a rubber grooming mitt or soft bristle brush.
- Long feline coat (Persian, Norwegian Forest Cat): Long hair fibers with heavy shedding. Requires daily brushing to prevent gastrointestinal blockages caused by hair ingestion.
Personalize their coat care by discovering their genetic origins. Explore Koko Genetics’ Dog DNA Tests and Cat DNA Tests to make the best decisions for their health and well-being.
