Our canine companions, however, cool themselves in an entirely different and somewhat less efficient manner. Unlike humans, they have very few sweat glands. The few they do have are located mostly in the pads of their feet. A hot or nervous dog will leave damp footprints on the surface it stands on, but these glands are not terribly effective at cooling the pet when it becomes overheated.
So, if dogs can't lower their body temperature by perspiration and evaporation on the surface of the skin, how do they keep their cool? Interestingly enough, they also use the process of evaporation, but in an entirely different way. Dogs primarily regulate their temperature by panting and breathing. The moisture on the surfaces of their tongue, mouth, and upper respiratory tract (including their intricate sinus cavities) evaporate as air passes over them. Dogs with shortened muzzles such as Pugs, Bulldogs, and Shih Tzu have more difficulty cooling themselves because their sinus cavities are far more compact. The air exchange moves heat from the body as it transfers in cooler air from the environment. However, if the air the dog is breathing is not considerably cooler than its body temperature, (101-102.5) this method of cooling cannot work properly and overheating could occur.
When dogs pant, they increase the speed of their respirations, but breathe more shallowly. The faster breathing exchanges the warm air from inside the body at a rapid rate. The lungs function in this capacity to not only exchange carbon dioxide for oxygen but also to lower the body temperature. While on this topic, it is important to note that dogs may also pant when they are nervous, afraid or ill.
Another way that dogs exchange heat is by expanding blood vessels that are located in the ears and on the face. The blood flows close to surface of the skin, where it can be exposed to cooler air before it recirculates to the rest of the body.
From this information we learn that it is important that dogs have cooler than body temperature air to breath in order to regulate their body heat and avoid heat exhaustion or heat stroke. If humidity is high, dogs will have more difficulty cooling than if the air is dry, because evaporation of the moist air they put out is hindered by high humidity.
Pets also need access to cool, fresh water at all times, especially if the weather is hot.
Although we share our hearts and homes with dogs, we need to keep in mind that the way humans and canines regulate heat if quite different from one another. This knowledge will help us know how to keep the dogs we love safe and healthy, even when the temperatures soar.
This article was written by Daryl Conner as a guest blogger