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.
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http://dx.doi.org/10.1038/s41598-020-60439-y | DOI Listing |
Curr Biol
November 2024
Laboratory of Artificial & Natural Evolution (LANE), Department of Genetics & Evolution, University of Geneva, 1211 Geneva, Switzerland; SIB Swiss Institute of Bioinformatics, 1211 Geneva, Switzerland. Electronic address:
The glabrous skin of the rhinarium (naked nose) of many mammalian species exhibits a polygonal pattern of grooves that retain physiological fluid, thereby keeping their nose wet and, among other effects, facilitating the collection of chemosensory molecules. Here, we perform volumetric imaging of whole-mount rhinaria from sequences of embryonic and juvenile cows, dogs, and ferrets. We demonstrate that rhinarial polygonal domains are not placode-derived skin appendages but arise through a self-organized mechanical process consisting of the constrained growth and buckling of the epidermal basal layer, followed by the formation of sharp epidermal creases exactly facing an underlying network of stiff blood vessels.
View Article and Find Full Text PDFJ Morphol
March 2021
Department of Biology, Lund University, Sölvegatan 35, 22362, Lund, Sweden.
The glabrous skin around the nostrils in mammals is called a rhinarium or planum nasale. Rhinarium skin has multiple epidermal domes that are generally assumed to form a tactile surface. The rhinarium is innervated by a branch of the trigeminal nerve which is associated with stimuli such as touch, chemical irritants and temperature.
View Article and Find Full Text PDFSci Rep
February 2020
Lund University, Department of Biology, Mammalian Rhinarium Group, Sölvegatan 35, 22362, Lund, Sweden.
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.
View Article and Find Full Text PDFJ Morphol
March 2020
Unit of Functional Zoology, Department of Biology, Lund University, Lund, Sweden.
A new morphological type of somatosensory organ is described. It is found in the glabrous skin of the dog nose (rhinarium or planum nasale) and situated in dermis papillae. The otherwise thick epidermis forms a thin window above the organ.
View Article and Find Full Text PDFJ Therm Biol
December 2017
Department of Biology, Lund University, Sweden.
Many mammals have specialized nose-tips with glabrous and often wet skin, called rhinaria. The function of the rhinarium is unknown in most species. Rhinaria differ not only in shape and skin structure, but also in skin temperature.
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