Why Can’t Dogs Handle the Heat.

02 Jan Why Can’t Dogs Handle the Heat.

What happens when we get too hot? We sweat, all over. But it’s actually the evaporation of the perspiration from our skin that provides the cooling effect. This aids in our Thermoregulation, the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is different. Both dogs and humans can Thermoregulate, but to a different degree and in much different ways.

First off, dogs (and cats) don’t sweat – at least not for the purpose of cooling down. Dogs produce “sweat” on areas not covered with fur, such as around the ears, nose and paw pads. But these secretions are insufficient to cool the animal and are more for moisture (to keep a dog’s nose from getting too dry or cracked pads) and to produce scents to allow recognition by other animals. But dogs do have a few other ways to cool off.

Ever notice how, on a hot day, you’ll find your dog lying on the cooler kitchen tile, rather than on the living room rug? That’s because dogs are able to transfer some internal heat to surfaces cooler than they are. But put a dog in a hot car and every surface, very quickly, becomes hotter than the dog – some surfaces even too hot to touch. (Ever grabbed a black steering wheel on a hot day? Ouch!) In a hot car a dog cannot cool off using this process of conduction.

Dogs often jump in pools or lakes to cool off. Convection transfers heat away from the animal through cooler air or water. But this process of cooling down is not available to a dog in a parked car either.

On a related side note; if a dog does become overwhelmed by heatstroke, it is not advised to submerge the entire dog in water or pour ice-cold water over the dog as the different temperatures are too much to regulate quickly (use tepid or cool water). Additionally, long-haired dogs can become waterlogged causing the fur to hold in the heat and not let it escape. As you pour water over a dog, wipe off the excess with your hand, helping to remove the heat as well and not let the dog’s fur trap in the heat.

And what about all that fur? Counter intuitively, fur can help an animal cope in warm temperatures. “Fur actually insulates the body in cold weather and helps prevent the body from taking on too much heat in warm weather,” says James H. Jones, an expert in comparative animal exercise physiology and thermoregulation at University of California at Davis. “Fur acts as a thermal regulator to slow down the process of heat absorption.” But there’s a limit! Put that dog in a parked car and as the temperature quickly rises, that fur coat will no longer help, but rather start to hurt the animal. Their fur begins to trap heat rather than fend it off, making the animal even hotter.

A dog’s main method of cooling off is to pant. Panting is when a dog takes quick, shallow breaths through an open-mouth, often with his tongue sticking out. This helps to evaporate water from the moist lining of the oral cavity, cooling the animal. Panting however, can actually add to the heat in a parked car and speed up the overheating of the animal. That’s because a dog’s body heat and expired air in the dog’s breath – which is normally about 102 degrees (39 Celsius) and has 100% humidity – will act like a heater inside the enclosed space of a car, making it hotter, more humid and harder for the animal to breathe/pant. Additionally, panting, especially when in distress, is a rather physical activity and as an animal overheats they get stressed and pant even harder, creating more activity that only further raises their temperature and generates more heat inside the car.

Another difference between dogs and us is our temperature. Most people think of the “normal” human body temperature as 98.6 degrees (37 Celsius). But dogs and cats normally run hotter. Like us, they are homeotherms (warm blooded), which means the animal maintains a fairly constant body temperature, but, in the case of dogs, their “normal” body temperature is 101 to 102 degrees. “The trick to being a homeotherm is to be able to adjust internal heat gain and heat loss… in order to maintain a constant body temperature,” Jones said. But a quick way to take away a dog’s ability to regulate his temperature is to put him in a parked car for a few minutes and, well, literally cook him alive. No homeotherm can regulate in an oven.

You’ve also got to consider that a dog, much like a child in a hot car, can’t open the doors and jump out. Neither can they call 911 or let you know what’s wrong. If a dog’s body temperature rises above 106 degrees, there can be brain, tissue and organ swelling, with abnormal blood clotting that can damage the kidneys, heart, lungs and brain – all in a matter of minutes! Animals eventually collapse and go into a coma, at which point seizure and respiratory arrest develop. A veterinarian who has performed autopsies on dogs that died this way said the organs are “soupy.” And this can happen hours or even days after the animal is removed from the hot car. (What are the signs of heatstroke in dogs?)

As you can clearly see, dogs are ill equipped to handle the heat inside a parked car, even for a few minutes! If you think your dog can take the heat and continue to take chances by leaving him or her in a parked car while you run into the store for “a few minutes,” you truly are playing Russian roulette with their lives.

As one animal-control officer put it, you might as well put your dog in a microwave – because it’s the same thing as leaving your animal in a hot car… you are literally cooking your dog from the inside out in a matter of minutes.