“Dogs only sweat through their tongues.”

It's a common sight: a dog on a hot day, tongue lolling, panting heavily. This very visible effort to cool down has led many to believe that dogs only sweat through their tongues, making panting their sole method of temperature regulation. The truth, however, is a little more complex and fascinating, revealing that our canine companions have more than one trick for beating the heat.

While panting is indeed a crucial and highly effective way for dogs to cool themselves by evaporating moisture from their tongues and respiratory tracts, it isn't their only means of sweating. Dogs possess merocrine sweat glands, similar to those found in humans, but these are primarily concentrated in their paw pads. When a dog gets warm, these glands release sweat onto the paw pads, which then evaporates and helps to dissipate heat from their bodies. This less obvious form of sweating often goes unnoticed, contributing to the widespread misconception. Dogs also have apocrine glands distributed throughout their bodies, but these are mainly involved in producing scent for communication, not for cooling.

The persistent belief that dogs only sweat through their tongues stems from the prominent role panting plays in their thermoregulation. The visible nature of a dog's panting, especially when they are hot or exercising, creates a strong impression that this is their exclusive cooling mechanism. Because their paw pads are often covered by fur and are less directly observed, the function of the merocrine glands there is easily overlooked. Understanding both panting and paw pad sweating gives us a more complete picture of how dogs keep cool.