“Why do dogs have cold noses?” wonder many humans who, most of them, have warmer noses than dogs have. Here are two research studies by Ronald H.H. Kroger and colleagues, that sniffed into the question and may have found some answers.
Dog Nose-Tip Distant-Heat Sensing Ability?
“Dogs Can Sense Weak Thermal Radiation,” Anna Bálint, Attila Andics, Márta Gácsi, Anna Gábor, Kálmán Czeibert, Chelsey M Luce, Ádám Miklósi, and Ronald H.H. Kröger, Scientific Reports, vol. 10, no. 1, 2020, 3736.
The authors, at Lund University, Sweden; Eötvös Loránd University, Hungary; and University of Bremen, Germany, explain:
“The dog rhinarium (naked and often moist skin on the nose-tip) is prominent and richly innervated, suggesting a sensory function. Compared to nose-tips of herbivorous artio- and perissodactyla, carnivoran rhinaria are considerably colder. We hypothesized that this coldness makes the dog rhinarium particularly sensitive to radiating heat. We trained three dogs to distinguish between two distant objects based on radiating heat; the neutral object was about ambient temperature, the warm object was about the same surface temperature as a furry mammal. In addition, we employed functional magnetic resonance imaging on 13 awake dogs, comparing the responses to heat stimuli of about the same temperatures as in the behavioural experiment…. Our results demonstrate a hitherto undiscovered sensory modality in a carnivoran species.”
Dog Nose-Tip Temperature Dynamics
“Rhinarium Temperature Dynamics in Domestic Dogs,“, Ronald Heinz Herbert Kröger and Aitor Bereber Goiricelaya, Journal of Thermal Biology, vol. 70, Part B, December 2017, pp. 15-19. The authors, at Lund University, Sweden, report:
“The rhinaria of adult, alert, and comfortable dogs are colder than ambient temperature from 30 °C (approximately 5 °C colder) down to a break point at about 15 °C. At an ambient temperature of 0 °C, rhinarium temperature is approximately 8 °C and the decrease in skin surface temperature with decreasing ambient temperature has not yet leveled off. The dog rhinarium warms up under a number of circumstances. In contrast to the continuously warm rhinaria of herbivores, our results suggest strongly that the cold state is the operating state of the dog rhinarium.”
Words to Remember, and Use
We suggest that you memorize that final, stirring phrase from the temperature dynamics paper— and recite the phrase in any meeting you attend, on any subject, when the meeting has reached its moment of maximum dullness: “our results suggest strongly that the cold state is the operating state of the dog rhinarium.”