All dog owners have had their pet smash their nose against their face or other body parts. Often dog noses are cold and slimy feeling, but other times they are warm and dry. Most pet owners have, at some point, wondered if their dog’s nose should be wet or dry. Researchers have recently investigated the noses of animals and determined that it is normal for a dog’s nose to be cold and wet, but it’s also normal for a dog to have a warm and dry nose.
Researcher Anna Bálint from Eötvös Loránd University in Budapest, Hungary, studies animal behavior. She says that when a dog sleeps, their nose usually warms up and dries out. When the dogs wake up, they lick their nose and goes back to being cold and wet. Researchers wanted to know if there was a benefit to the dog’s nose being cold.
One hypothesis was that the cold nose could help the dog regulate body temperature, but the tip is so small it’s unlikely to contribute meaningfully to thermal regulation. The research team measured the temperature of many animal noses, including noses of horses, dogs, and moose. The team determined that the nose tips of dogs and carnivorous animals are typically cooler than those of herbivores.
The next step was to figure out if a cooler nose offered carnivorous animals an advantage in the wild. The team conducted experiments looking at behavior and the brain to see if a cold nose made for better heat detection. The team successfully trained three dogs to choose a warmer object that was about the same temperature as potential prey over an object at room temperature.
Results indicated dogs can detect weak thermal radiation from a distance when hunting prey. In the second brain-centric investigation, scientists presented a box containing warm water and an insulating door to 13 dogs trained to lie still in a functioning MRI scanner. The dogs’ brains had a higher response when insulating doors open, revealing the warmer surface compared to when the door was closed, and the surface was cooler.
Specifically, the left hemisphere of the brain lit up in these tests, which is the side that tends to process responses to food and is linked to predatory activity in many vertebrates. The researchers believe that dogs and other cold-nosed animals could be using heat detection sense along with other senses when on the hunt.