Panting in reindeer (Rangifer tarandus).
Two winter-insulated Norwegian reindeer (Rangifer tarandus tarandus) were exposed to air temperatures of 10, 20, 30, and 38 degrees C while standing at rest in a climatic chamber. The direction of airflow through nose and mouth, and the total and the nasal minute volumes, respectively, were determined during both closed- and open-mouth panting. The animals alternated between closed- and open-mouth panting, but the proportion of open-mouth panting increased with increasing heat load. The shifts from closed- to open-mouth panting were abrupt and always associated with a rise in respiratory frequency and respiratory minute volume. During open-mouth panting, the direction of airflow was bidirectional in both nose and mouth, but only 2.4 +/- (SD) 1.1% of the air was routed through the nose. Estimates suggest that the potential for selective brain cooling is markedly reduced during open-mouth panting in reindeer as a consequence of this airflow pattern.
Aas-Hansen
O
O
Department of Arctic Biology and Institute of Medical Biology, University of Tromsø, N-9037 Tromsø, Norway.
Folkow
L P
LP
Blix
A S
AS
D000818:Animals; D001833:Body Temperature Regulation / Q000502:physiology*; D001921:Brain / Q000502:physiology; D003081:Cold Climate; D005260:Female; D008954:Models, Biological; D009055:Mouth; D009664:Norway; D009666:Nose; D012053:Reindeer / Q000502:physiology*; D015656:Respiratory Mechanics / Q000502:physiology*; D012621:Seasons; D013696:Temperature; D013990:Tidal Volume