Metabolism, Respiration and Evaporative Water Loss in the Australian Hopping-Mouse Notomys Alexis (Rodentia: Muridae).

1979 ◽  
Vol 27 (2) ◽  
pp. 195 ◽  
Author(s):  
PC Withers ◽  
AK Lee ◽  
RW Martin

Resting oxygen consumption and total evaporative water loss were determined for N. alexis at ambient temperatures of 20, 28 and 33 deg C in dry air. The minimum rate of oxygen consumption was 0.61 ml min-1 at 33 deg C, and minimum total evaporative water loss was 4.75% body mass day-1 at 28 deg C. Respiration frequency, tidal volume and respiratory minute volume were determined for N. alexis at ambient temperatures of 20, 28 and 33 deg C in air of low or high relative humidity. Minimum values were obtained at 28 deg C and low RH for respiratory minute volume and tidal volume, and at 28 deg C and high RH for respiratory frequency. Expired air temperature of N. alexis at these temperatures was lower than or similar to ambient for mice in air of low RH, but was higher than or similar to ambient at high RH. Respiratory evaporative water loss, calculated from the previous data, was greatest for mice in dry air at 33 deg C, and least in moist air at 33 deg C. Cutaneous evaporative water loss made up about 40-60% of the total evaporative water loss for mice in dry air. The rates of total evaporative water loss were clearly reflected in the manner of body temperature regulation at high ambient temperatures. Hopping-mice in moist air at 28 and 33 deg C became hyperthermic, whereas mice in dry air showed only slight increases in body temperature. The significance of these data to hopping-mice in the field was discussed.

1986 ◽  
Vol 34 (1) ◽  
pp. 25 ◽  
Author(s):  
JR Roberts ◽  
RV Baudinette

Stubble quail occur in more arid areas of Australia than king quail; however, the rates of metabolism and the ability to regulate body temperature in response to varying ambient temperature are similar in both birds, and resemble those of other quail species. At high ambient temperatures, rates of heat loss mediated by evaporative water loss are lower than those previously reported for more xerophilic species. Overall rates of water turnover and evaporative water loss at lower ambient temperatures are at the lower end of the range predicted for birds.


1976 ◽  
Vol 24 (1) ◽  
pp. 39 ◽  
Author(s):  
WW Weathers ◽  
DC Schoenbaechler

The standard metabolic rate of budgerygahs, determined during October and November, was 30% lower at night (1.96 ml O2 g-1 h-1) than during the day (2.55 ml O2 g-1h-1 ). The zone of thermal neutrality extended from 29 to 41�C. At ambient temperatures (Ta) below 29�C, oxygen consumption [V(02)] increased with decreasing Ta according to the relation V(02) (ml O2 g-1 h-1) = 5.65 - 0.127Ta. At Ta's between 0 and 16�C, body temperature (Tb) averaged 37.7�C (which is low by avian standards) and was independent of Ta. Above 20�C, Tb increased with increasing Ta, and within the zone of thermal neutrality Tb increased by approximately 4�C. The relation between V(O2) and Tb within the zone of thermal neutrality is described by the equation V(O2 = 6.29 - 0.105 Tb. This ability to decrease metabolic heat production while Tb rises could contribute to the water economy of budgerygahs. At moderate Ta's the rate of evaporative water loss of budgerygahs is only 60% that predicted for a 31 g bird. At Ta's below 14�C budgerygahs can balance evaporative water loss with metabolic water production. At 45�C Tb was between 1.0 and 5.0�C below Ta, and evaporative cooling accounted for up to 156% of metabolic heat production. At high Ta's budgerygahs appear to augment evaporation by lingual flutter.


The Condor ◽  
1962 ◽  
Vol 64 (2) ◽  
pp. 117-125 ◽  
Author(s):  
George A. Bartholomew ◽  
Jack W. Hudson ◽  
Thomas R. Howell

1978 ◽  
Vol 29 (1) ◽  
pp. 161 ◽  
Author(s):  
PS Hopkins ◽  
GI Knights ◽  
AS Le Feuvre

Rectal temperature measurements of tropical Merino sheep taken in the sun during summer indicated that there were high and low temperature groups. Animals of low temperature status (e.g. 39.4°C) also exhibited a low respiration rate (e.g. 110/min) in comparison with their less adapted counterparts (40.0° and 190/min). These differences were greatest when ambient temperatures were high. The repeatability of temperature status was 0.46 (P < 0.01). Animals of folds (+) phenotype had significantly higher rectal temperatures than folds (–) animals (P < 0.05). Shearing caused a marked but transient increase in rectal temperature. Compensatory mechanisms apparently involved an increase in cutaneous heat dissipation and/or a decrease in exogenous heat load. Evaporative water loss (80–115 ml/kg/day) greatly exceeded the non-evaporative water loss (40–65 ml/kg/day) of sheep in metabolism cages. Respiratory water loss could account for only 8–10% of the total daily evaporative water loss. Non-respiratory evaporative water loss (as measured by difference) was c. 75–100 ml/kg/day. There were no striking differences between high and low temperature status sheep in this regard. Measurements of respiratory (2 ml/kg/hr) and non-respiratory (5.5 ml/kg/hr) evaporative water loss made in hygrometric tents suggested that the greater non-respiratory water loss was partly due to a higher rate of loss and partly to a longer period of loss per day. This suggestion was supported by the diurnal patterns of rectal temperatures and respiration rates reported here, though no firm conclusions could be made as to the thermotaxic effect of non-respiratory water loss and thermoregulation of tropical Merinos with varying amounts of wool cover.


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