Effects of Water Vapor Density on Cutaneous Resistance to Evaporative Water Loss and Body Temperature in Green Tree Frogs (Hyla cinerea)

2013 ◽  
Vol 86 (5) ◽  
pp. 559-566 ◽  
Author(s):  
Mark L. Wygoda ◽  
Constance A. Kersten
Keyword(s):  
Water Vapor ◽  
Body Temperature ◽  
Water Loss ◽  
Evaporative Water Loss ◽  
Vapor Density ◽  
Hyla Cinerea ◽  
Evaporative Water ◽  
Tree Frogs ◽  
Cutaneous Resistance

Physiological responses of a rodent to heliox reveal constancy of evaporative water loss under perturbing environmental conditions

2014 ◽  
Vol 307 (8) ◽  
pp. R1042-R1048 ◽  
Author(s):  
Christine Elizabeth Cooper ◽  
Philip Carew Withers
Keyword(s):  
Water Vapor ◽  
Metabolic Rate ◽  
Environmental Conditions ◽  
Water Loss ◽  
Physiological Responses ◽  
Ambient Air ◽  
Minute Volume ◽  
Evaporative Water Loss ◽  
Evidence Based ◽  
Evaporative Water

Total evaporative water loss of endotherms is assumed to be determined essentially by biophysics, at least at temperatures below thermoneutrality, with evaporative water loss determined by the water vapor deficit between the animal and the ambient air. We present here evidence, based on the first measurements of evaporative water loss for a small mammal in heliox, that mammals may have a previously unappreciated ability to maintain acute constancy of total evaporative water loss under perturbing environmental conditions. Thermoregulatory responses of ash-grey mice ( Pseudomys albocinereus) to heliox were as expected, with changes in metabolic rate, conductance, and respiratory ventilation consistent with maintaining constancy of body temperature under conditions of enhanced heat loss. However, evaporative water loss did not increase in heliox. This is despite our confirmation of the physical effect that heliox augments evaporation from nonliving surfaces, which should increase cutaneous water loss, and increases minute volume of live ash-grey mice in heliox to accommodate their elevated metabolic rate, which should increase respiratory water loss. Therefore, mice had not only a thermoregulatory but also a hygroregulatory response to heliox. We interpret these results as evidence that ash-grey mice can acutely control their evaporative water loss under perturbing environmental conditions and suggest that hygroregulation at and below thermoneutrality is an important aspect of the physiology of at least some small mammals.

Measurement of evaporative water loss in small animals by dew-point hygrometry

1977 ◽  
Vol 43 (2) ◽  
pp. 382-385 ◽  
Author(s):  
M. H. Bernstein ◽  
D. M. Hudson ◽  
J. M. Stearns ◽  
R. W. Hoyt
Keyword(s):  
Water Vapor ◽  
Water Loss ◽  
Water Vapor Pressure ◽  
Columba Livia ◽  
Evaporative Water Loss ◽  
Dew Point ◽  
Small Animals ◽  
Evaporative Water ◽  
Open Flow ◽  
Two Temperatures

This paper presents the procedures and equations to be utilized for measurement of evaporative water loss (mw), by use of the dew-point hygrometer, in small animals exposed to air containing water vapor in an open-flow system. The system accounted accurately for the water evaporated from a bubble flask. In addition, hygrometric measurements of pulmocutaneous mw in pigeons (Columba livia, mean mass 0.31 kg) agreed closely with simultaneous gravimetric measurements, utilizing a desiccant in the sample stream, in a manner independently of air temperature (Ta, 20 or 40 degrees C), ambient water vapor pressure (PW, 4–16 10(2) Pa), or mw (5–66 mg-min-1). Evaporation in pigeons was independent of PW at 20 degrees C, but increased with decreasing PW at 40 degrees C, suggesting differences in ventilatory adjustments to changes in PW at the two temperatures.

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