We've all seen dogs panting on a hot day or after an intense game of fetch, but that's not the only way they cool down. It may be surprising, but dogs actually do sweat, just not the same way or for the same reasons that humans do.
How do dogs sweat?
Sweat has a pretty limited job for dogs when it comes to cooling off. Dogs do have sweat glands—two kinds, to be exact —but unlike humans, a dog's sweat glands do a slightly different job than just canine cooldown. These glands serve to create a small amount of sweat, moderate salt content in the body, help eliminate metabolic waste, as well as produce some pretty heady body odor.
When a dog gets hot, whether it is from an increase in internal temperature from exercise or simply being outside on a hot day, the special sweat glands called merocrine glands go to work. Merocrine glands are located in your dog's paw pads and will produce sweat to help cool off your dog's feet. Humans, apes, dogs, and rats all have sweat glands on their palms or foot pads that serve to cool us off, however, for humans, these sweat glands can be emotionally triggered. (Sweaty palms, anyone?) You may have noticed your dog leaving wet footprints on a hot day. While it is possible she's been playing in her water dish, it is more likely that her body is keeping cool through her feet.
Not only that, the sweat coming off your dog's paw pads might actually be less useful for cooldown, and more likely helping her to keep her footing. According to researcher and veterinarian Catherine Carrier, known for her work with beagles, the wetness on a dog's paws makes them feel tacky, helping them stick to the ground, giving the dog better traction.
Dogs also have apocrine glands which are located all over your dog's body. These glands don't produce sweat so much as they produce scent. Pheromones are one of the main ways that dogs communicate with one another, and the apocrine gland is kind of like a body odor machine. As we know, a dog's sense of smell is an incredibly powerful tool. Dogs use these smells and pheromone information to recognize each other.
Cooling down by panting
When a dog starts to feel hot and begins to overheat, his paw pads might sweat a little, but more likely you will notice him panting. We've all seen it: the mouth opens, the tongue rolls out, and Fido takes big, body-shaking doggy breaths.
Panting helps to oxygenate the bloodstream which is especially important after exercise or exertion on a hot day. Blood that is full of oxygen will enter into the tissues of your dog's skin in his ears and face. This process of vasodilation, when the blood goes to the surface of the dog's body, helps to cool down your dog and lower his core body temperature. Panting also cools off your dog's tongue. The process of breathing in draws air over the tongue, causing the moisture in his mouth to evaporate which helps to cool him off.
The importance of keeping cool
Because dogs don't sweat like humans do, it's important that they have the opportunity to cool down. If you're playing with your dog, be sure to give him water breaks and the opportunity to rest in the shade. Providing fresh water or even making electrolyte water for him to drink can also help him keep cool. Heat stress, heat exhaustion, or heat stroke are all major concerns for dogs since they have a built in fur coat and their natural cooling abilities are not as efficient as a human's. Brachycephalic dogs like Bulldogs, pugs, and boxers are especially at risk on a hot day, and may need some extra cool-down time after playing.