Why do dogs have wet and cold noses?
The tip of a dog's nose is almost always wet and cool. Many pet owners even try to determine by this sign whether everything is in order with their pet’s health. This method is very controversial, but still, a awake and active dog’s nose is actually wet. What is this connected with and how does it help the animal in its life?
The mucus that covers the canine sense of smell is secreted by special glands lining the nose. Have you noticed that a wet body is much more sensitive to external factors than a dry one? Also, many people salivate on their finger and raise it to determine the direction of the wind. In dogs, everything works on the same principle. A wet nose detects the faintest air movements as accurately as possible. This allows dogs to always “keep their nose in the wind.”
But that is not all. The mucus-covered nose acts as a gas-liquid chromatograph. Molecules hitting a wet surface move at different speeds. This allows receptors to “sort” them. This is why dogs are so good at smelling. In this case, not only the internal, but also the external surface of the nose takes part in the analysis.
The surface of the nose is bare skin full of glands called rhinarium. It is penetrated by a huge number of nerve endings. Its normal temperature is 5 degrees lower than that of the environment. And this helps dogs distinguish not only smells, but also temperature differences.
An experiment was once conducted at Land University in Sweden. There, three dogs were trained to distinguish between an object heated to 31 degrees Celsius and an object with ambient temperature at a distance of 1.6 meters. The objects had no odor and were hidden from the eyes of the animals with a screen. Nevertheless, the dogs accurately found the warm object.
At the University of Budapest. Eotvega Laurenda repeated the experiment. But at the same time, an encephalogram was also performed to determine in which part of the brain activity occurs during choice. The area responsible for the sense of smell produced impulses when the dog paid attention to a warmer object.
Most mammal species have wet noses. The only unlucky ones were humans and other real monkeys, as well as tarsiers. Having become diurnal animals, these species rely less on smell and more on vision. The sensitive nose turned out to be superfluous and gradually lost most of its abilities.
For dogs, the nose has been and remains the main tool for understanding the surrounding world. Although the statement that these animals have poor vision and are generally colorblind is quite controversial, it is certain that vision will never replace their sense of smell.