It was a warm, spring day and a neighbor and I were watching some dogs charging around playfully in a fenced, dog-park area, seemingly oblivious to the heat. My neighbor commented, “You know, if we were running around like that we would be drenched in sweat. Dogs must be marvelously adapted to handle the heat.”
In truth, dogs are designed to handle cold better than heat. For humans, our major method of keeping cool is through perspiration. As our sweat evaporates, it results in a cooling effect, which lowers our body temperature. Dogs don’t.
Dogs have two types of sweat glands: merocrine glands (similar to human sweat glands) and apocrine glands. Merocrine glands are not widely distributed as they are in people but are mostly found in the paw pads. Sweating through their paws helps dogs cool down, at least a little. The apocrine glands are located throughout the body, and these also produce sweat in dogs, but this type of sweat doesn’t serve a cooling function. Rather, apocrine sweat contains pheromones, which are scent cues that convey information about the dog and help dog-to-dog communication.