Groomer’s Guide
Understanding The Canine Integumentary System & How Dogs Cool Themselves
digital illustration of veterinarian holding magnify glass up to hair follicle under a skin barrier

by Jennifer Bishop Jenkins

We groomers are in the middle of a knowledge explosion that is revolutionizing our pet grooming industry; however, this explosion is still in process. And while not all pet groomers have had access to the new information about genetics, dermatology, and general science about dogs and their care, those who have had access—through either in-person education or the online education that is increasingly available to us—are at the forefront of applying this new information that is changing what we previously believed about certain grooming practices. One of the exciting subjects that more groomers are becoming increasingly more interested in and educated on is the canine integumentary system.

The Integumentary System

Mammal skin is the largest and most important organ in our bodies. It is incredibly complex and highly functional in several ways, performing many important jobs. Muller and Kirk’s Small Animal Dermatology lists 18 separate and vital functions for canine skin in “Chapter One,” including nutrient storage, temperature regulation, an immune system that provides protection from environmental toxins, hydration, sensory perception, vitamin D processing and protection as a barrier for all the other vital internal organs. The entire complex mammalian system of skin and hair, along with its many glands, layers and varied features, is called the integumentary system.
While this article cannot substitute for a real class in the canine integumentary system and its anatomy, we can all read up and study it on our own—there is a lot of information online for the groomer eager to learn more. In addition, I have found in conversations with clients, who know almost nothing themselves about skin and coat in dogs, that I often need to bust some myths or popular misconceptions often held by them about their dogs, with “Fur/hair makes a dog hot.” being one of the most common.
Client Education
Many is the client that came to me assuming that a dog that is panting heavily in the summertime is overly hot. They assume that the way to address it would be the same as for us humans—to take off our heavy winter clothes and wear lighter summer clothing. So, they ask me to take off all their dog’s hair because they are sure it is making them hot.
Panting to Cool
First I explain to them that dogs’ sweat glands don’t function as ours do and that panting is the way that dogs cool themselves. According to PetMD, “Panting is a normal behavior for happy and active dogs. It helps dogs cool themselves down because they can’t sweat like humans do. Panting allows a dog to rapidly inhale, humidify, then exhale the air, which increases the evaporation of water from your dog’s nose and lungs. The evaporation of water cools the body from the inside out.”1
Sweat Glands
Dogs have two types of sweat glands: apocrine glands and merocrine glands. Apocrine glands are the dog’s main source of hydration, but rather than leading to the surface of the skin, the apocrine gland deposits the cooling and hydrating water inside the hair follicle. So, take away their hair and they lose their ability to hydrate their skin. While veterinarians consider apocrine glands to be sweat glands, their main purpose is to release pheromones, not for cooling a dog off. These glands are located all over every dog’s body, and they help a dog identify other dogs by scent.2
digital illustration showing the difference between canine skin and human skin
Merocrine sweat glands function similarly to human sweat glands. Located in certain parts of dogs’ bodies that have no hair (i.e., the pads of their feet, their noses), these glands activate when a dog is hot to cool them down. This is why you might notice damp paw prints on the ground during particularly hot days. Most dogs are covered in fur, so if sweat glands were located on their bodies, the sweat would fail to evaporate, potentially soaking their coat and suffocating them. Cooling takes place when sweat evaporates. That’s why it is much more efficient for dogs to have sweat glands in their paw pads, where there is little fur.
The Function of Fur/Hair
Next I explain to the client that a dog’s hair or fur protects their pet from the heat. As described by Dr. Jerry Klein, Chief Veterinary Officer for the AKC, “Your dog’s coat actually acts as an insulator. A dog’s coat captures air to keep out the cold and hold heat in during winter, and to keep your dog cooler in hot weather. This is why you should not shave a double-coated breed. The inner coat, which is shed regularly, is also the dog’s insulating coat. Shaving that coat to reduce shedding or supposedly to keep the dog cool also eliminates that insulating layer of fur and makes the dog susceptible to heatstroke and can result in improper hair growth and the possibility of follicle damage.”2

In addition to sharing with my clients a laminated copy of Dr. Klein’s description of how the dog’s coat acts as an insulator, I ask them to imagine a man walking in the Sahara Desert wearing traditional North African clothing, which is basically light-colored, loose-fitting sheets that allow air flow to the skin to cool the wearer while the clothing reflects away the sun. Similarly, taking away a dog’s hair/fur actually makes them hotter because a well-groomed coat that is clean, conditioned, not matted and not clogged with undercoat reflects away the sun but also allows air flow to the skin for cooling. My clients seem to understand this image since going naked in the hot sun to stay cooler would be ridiculous.

Thin Skin
I also explain that a dog’s skin is much thinner than ours, with the epidermis (top layer) of a dog’s skin being 3-5 cells thick and in humans it is at least 10-15 cells thick.3 We also have just one hair in most of our follicles, while dogs have many more hairs per follicle and many more follicles. They rely on their more profuse coat to protect their thinner skin. Taking away a dog’s hair not only leaves their complex and fragile skin more vulnerable to toxins, parasites, injury and discomfort, but also puts them at greater risk for skin cancer.4

While we are both mammals, dogs and people are not the same when it comes to how their hair and skin work. One of our biggest problems is that many groomers do not know how different we are, and virtually none of our clients do. As a result, sometimes clients will unknowingly ask for something that will ultimately be bad for their dog and, also unknowingly, many groomers will carry out those requests. Dogs need their natural coats to protect them and we groomers are in the coat care business, not the coat destruction business.

References:
  1. Catalano, DVM, C. (2020, July 31). Why Do Dogs Pant? Is Your Dog Panting Too Much? PetMD. https://www.petmd.com/dog/behavior/evr_dg_why_do_dogs_pant
  2. Burke, A. (2024, March 26). Do Dogs Sweat? AKC. https://www.akc.org/expert-advice/health/do-dogs-sweat/
  3. Skin – the difference between canine and human skin. Vetwest. https://www.vetwest.com.au/pet-library/skin-the-difference-between-canine-and-human-skin
  4. Madewell, B., Conroy, J., & Hodgkins, E. (1981). Sunlight-skin cancer association in the dog: a report of three cases. Journal of cutaneous pathology, 8(6), 434–443. https://doi.org/10.1111/j.1600-0560.1981.tb01033.x
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