Dogs can sense weak thermal radiation

Anna Bálint,Márta Gácsi,Anna Gábor,Chelsey M Luce,Attila Andics,Kálmán Czeibert,Ronald H H Kröger,Ádám Miklósi

doi:10.1038/s41598-020-60439-y

Abstract

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. The warm stimulus elicited increased neural response in the left somatosensory association cortex. Our results demonstrate a hitherto undiscovered sensory modality in a carnivoran species.

Highlights

The dog rhinarium is prominent and richly innervated, suggesting a sensory function
In the raccoon (Procyon lotor) and the coati (Nasua nasua), two carnivoran species with well-developed rhinaria without Eimer’s organs, activity was elicited in the trigeminal ganglion by stimulation of the rhinarium skin with various non-chemical stimulus modalities[3]
The ability to sense weak thermal radiation has the potential of conveying valuable sensory information to an animal preying mainly on endothermic animals

Summary

Introduction

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 sensitive to radiating heat. In the raccoon (Procyon lotor) and the coati (Nasua nasua), two carnivoran species with well-developed rhinaria without Eimer’s organs, activity was elicited in the trigeminal ganglion by stimulation of the rhinarium skin with various non-chemical stimulus modalities[3]. Low tissue temperature affects metabolic functions in general and sensory sensitivity in particular (e.g.7), with one known exception: crotaline snakes cool their infrared-sensitive pit-organs by respiratory evaporation of water and strike more accurately with colder pit-organs[8]. For biological detectors of thermal radiation, the only option is to detect the warming of the tissue by the absorption of many long-wavelength photons[12]

Methods

Results

Conclusion