We chatter our teeth and shiver when we're cold, but when it comes to dogs, they may rely on different ways to stay warm. While we bundle up with extra layers of clothing, scarves and mittens, dogs must rely on their own "built-in" features along with some several other fascinating mechanisms Mother Nature has provided them with. In a past article we looked at ways dogs cool down, in this article instead, we will be discovering several fascinating ways dogs keep themselves warm.
Warm Double Coats
What's the purpose of a double coat? "It's meant to keep ourselves toasty!" says Rover. Just like our warm winter jackets, many dogs are protected from the rigors of the winter courtesy of their double coats.
A dog's undercoat consists of short and cotton-like hairs meant to insulate and prevent loss of body heat, while the top coat consists of stiff, moisture-repellent guard hairs meant to protect from the winter elements.
Several dog breeds have double coats and these include German shepherds, collies, sheepdogs, corgis, Beaucerons, Belgian malinois, Belgian tervurens, briards, Labrador and golden retrievers just to name a few.
More notoriously, spitz-type dogs are known for their double coats and include Siberian huskies, Samoyeds, Pomeranians, Akitas, Alaskan malamutes, chow chows, keeshonds, Shiba Inus, Norwegian elkhounds and Norwegian lundehunds.
"The thick undercoat of the Northern Breeds provides loft, like a fuzzy mohair sweater, and keeps the warmth next to the animal rather than allowing it to escape."~ Dr. Susan Whiton
The Power of Piloerection
On top of being equipped with warm coats, dogs have the ability to raise the hairs on their neck, back and tail. The term for this feature is piloerectionand it works in a similar fashion as goosebumps in humans.
Each dog hair is equipped with a hair follicle which in turn is attached to special muscles that are known as "arrector pili." When a dog is in a normal, relaxed state, his hair follicles will stay at a 30 to 60 degree angle compared to the skin.
Let the arrector pili muscles contract though and watch those hairs literally stand up, explains Karen L. Campbell, a board-certified veterinarian specializing in internal medicine and dermatology in the book "The Pet Lover's Guide to Cat and Dog Skin Diseases."
When us humans get cold, we develop goosebumps, while in dogs, if it's very, very cold, the contraction of the arrector pili muscles cause piloerection. The raised hairs in this case are meant to trap air and create a layer of insulation.
"A dog's hair will stand on end when he is very, very cold... When the hair stands up, an insulating layer of air gets trapped between hair shafts, so the cold air cannot get so close to the skin. It works like a down jacket." Dr. Nicholas Dodman
Paw Heating System
Ever wondered how dogs keep their paws from freezing? Let's think about it. As the weather gets colder, we put on thick socks and boots, while our dogs walk completely barefoot on wet and sometimes even icy surfaces, how do they manage to do that?
In this case, we must thank the dog's almighty paws. Blessed with tough padding made of layers of insulating fat and connective tissue, a dog's paws are also equipped with an impressive number of blood vessels. This means greater circulation which helps prevent those paws from getting frozen.
Interestingly, a study conducted by scientists at Tokyo's Yamazaki Gakuen University found that the arteries responsible for providing blood to a dog's paw pads have several networks of tiny veins nearby (venules). The proximity of arteries and veins results in heat exchange, acting as a counter-current heat exchanger. This artery and vein heat circulation system seems to suggest that the ancestors of the domestic dog may have originated in a cold climate.
"It is well known that penguins in the Antarctic have a counter current heat exchange system in their wings and legs to prevent heat dissipation and keep the body warm. When we found that dogs also have such an excellent system in their paws, we were excited."~Dr Hiroyoshi Ninomiya.
Curling Like a Ball
When dogs are cold, they instinctively seem to know that certain sleeping positions are better. Sleeping in a curled up position, tight like a ball, is a dog's way to conserve heat.
By sleeping this way, the dog's body surface is made as small as possible and the loss of heat is minimized.
If it's very cold, dogs will sleep with their tails covering their noses, an astute strategy to maximize their ability to stay warm. A bushy tail helps protect the dog's eyes, nose, muzzle and front legs from cold, and on top of that, it acts like a filter, allowing a dog to breath in pre-heated air. How cool is that?
Did you know? Some dogs in very cold climates may utilize what's known as "social thermal regulation." According to the book "K9 Complete Care: A Manual for Physically and Mentally Healthy Working Dogs"by Resi Gerritsen, Ruud Haak, arctic explorers mentioned how dogs in Southern Greenland slept very close to each other near their homes so to keep warm and out of the wind.
Shivering to Warm Up
Not all dogs are blessed with warm double coats, and those who lack it, are more likely to get cold.
Small, short-haired dog breeds are in particular predisposed to chilling as they tend to lose their body heat quite rapidly.
It's not unusual to see dachshunds and Chihuahuas seek out the warmest areas of the house, burying themselves under blankets or staying right next to the fireplace in order to stay warm.
Trembling is something that dogs just like humans do so to generate heat and raise body temperature, explains Erich Barchas, a veterinarian in San Francisco.
If your dog is shivering though and it is not cold, consider evaluating the underlying cause, as shivering in dogs can also be seen in dogs who are scared, in pain, sick or experiencing some health problem.
A Word of Caution
Sure, many dogs have the ability to cope in cold weather, and if they are new to cold, they can acclimate fairly quickly, given the chance. However, this does not mean that our dogs are not immune from the effects of prolonged exposure to bitter cold. Just like us, dogs can get frostbite, and suffer other serious consequence of cold.
Not all dogs experience cold in the same way, and some dogs are definitely at a disadvantage. Small dogs, short-haired dogs, short dogs who are lower to the ground, older dogs, dogs with certain medical conditions, skinny dogs and young puppies may not be able to regulate their temperatures well and may need our intervention to be protected from the dangers of winter weather.
"In general, there are three kinds of dogs who benefit from the insulation provided by a sweater or coat, as well as the protection afforded by life as a pampered house pet: Small dogs, dogs who are elderly, chronically ill or both, Greyhounds, Whippets and dogs of a similar thin body type, especially those with short fur. ~Dr. Marty Becker
- Veterinary Dermatology, Volume 22, Issue 6, pages 475–481, December 2011. DOI: 10.1111/j.1365-3164.2011.00976.
- K9 Complete Care: A Manual for Physically and Mentally Healthy Working Dogs, By Resi Gerritsen, Ruud Haak, Dog Training Press (January 1, 2003)
- Painting by John Emms portraying St. Bernards as rescue dogs, Public Domain