What is the name of the beard of a dog? - briefly
The area on a dog's face where hair grows longest is commonly referred to as the "beard" or "chin."
What is the name of the beard of a dog? - in detail
The term used to describe the facial hair on a dog's muzzle, commonly referred to as a "beard," is more accurately known as a "mustache" or "whiskers." These hairs play a crucial role in canine sensory perception and are an integral part of their facial structure. The whiskers, which are longer and coarser than the surrounding fur, act as tactile sensors that help dogs navigate their environment by detecting changes in air currents and contact with surfaces or objects. This intricate system aids in their ability to locate prey, assess their surroundings, and even communicate subtle emotions. Therefore, while it may be colloquially referred to as a "beard," the correct terminology for the hair on a dog's muzzle is indeed "mustache" or "whiskers."