Energetics of the Little Penguin, Eudyptula Minor: Temperature Regulation, the Calorigenic Effect of Food, and Moulting.

1986 ◽  
Vol 34 (1) ◽  
pp. 35 ◽  
Author(s):  
RV Baudinette ◽  
P Gill ◽  
M O'driscoll
Keyword(s):  
Heat Production ◽  
Water Loss ◽  
Thermal Conductance ◽  
Fold Increase ◽  
The Body ◽  
Evaporative Water Loss ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Effect Of Food ◽  
Little Penguin

Rates of oxygen consumption and means of augmenting the resultant heat production were studied in the little penguin, Eudyptula minor. Metabolic rates were lower than those predicted for a 1-kg bird, but shivering and an energy response to feeding were both present. The latter effect was independent of ambient temperatures between 2 deg and 22 deg C. The birds have limited ability to dissipate heat by evaporative water loss. About 40% of the total heat production was the maximum amount lost by this route. Cooling of expired respiratory gas provided an effective saving of heat and water. Moulting resulted in a 1.5-fold increase in metabolic rate but rates of evaporative water loss were reduced. The increase in heat production is correlated with increased thermal conductance across the body surface, as new feathers are synthesized, but body temperature is the same as in non-moulting penguins. The results suggest that increased heat loss when the birds are in water might be replaced by calorigenesis associated with the response to feeding, and by shivering, as well as by activity.

Thermal Biology and Metabolism of the Greater Long-eared Bat, Nyctophilus major (Chiroptera :Vespertilionidae)

1997 ◽  
Vol 45 (2) ◽  
pp. 145 ◽  
Author(s):  
D. J. Hosken
Keyword(s):  
Water Loss ◽  
Thermal Conductance ◽  
Carbon Dioxide Production ◽  
Evaporative Water Loss ◽  
Detectable Effect ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Fat Reserves ◽  
Metabolic Physiology ◽  
Vespertilionid Bats

Nyctophilus major is the largest member of its Australian-centred genus. Flow-through respirometry was used to investigate the thermal and metabolic physiology of adult N. major from south-western Australia. Oxygen consumption, carbon dioxide production, respiratory quotient, evaporative water loss and thermal conductance were measured at ambient temperatures of 5–40C. N. major was thermally labile and could be euthermic or torpid at low Ta. N. major entered into and spontaneously aroused from torpor at Tas as low as 5C, and became torpid at Tas as high as 23C. Like other temperate-zone Australian vespertilionid bats, some torpid N. major maintained a relatively high Tb at low Ta. Body mass and the duration of captivity had no detectable effect on the thermal responses of bats. The basal metabolic rate (BMR) of N. major was 85% of predicted, and falls within the the range of mass-specific BMRs reported for vespertilionid bats. While mean torpid á VO2 was reasonably high, torpor still facilitates substantial metabolic savings. However, because of the high á VO2 , N. major may not be able to remain torpid for more than about 60 days, relying solely on fat reserves. The evaporative water loss (EWL) of euthermic and torpid N. major was also high, although EWL during torpor was reduced compared with euthermy. Wet conductance was lower than predicted and probably relates to the solitary, tree-roosting habits of N. major. As has been reported for other bats, conductance values during torpor were lower than those during euthermy, but when torpid bats maintained a large ( Tb – Ta) differential at low Ta or became torpid at relatively high Ta , conductance values approached euthermic levels.

Regulation of body temperature in the Budherygah, Melopsittacus undulatus

1976 ◽  
Vol 24 (1) ◽  
pp. 39 ◽  
Author(s):  
WW Weathers ◽  
DC Schoenbaechler
Keyword(s):  
Body Temperature ◽  
Heat Production ◽  
Water Loss ◽  
Standard Metabolic Rate ◽  
Evaporative Water Loss ◽  
Metabolic Heat Production ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Metabolic Heat ◽  
Metabolic Water

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.

scholarly journals Heat Production From Foraging Activity Contributes to Thermoregulation in Black-Capped Chickadees

The Condor ◽  
2007 ◽  
Vol 109 (2) ◽  
pp. 446-451 ◽  
Author(s):  
Sheldon J. Cooper ◽  
Sarah Sonsthagen
Keyword(s):  
Heat Production ◽  
Water Loss ◽  
Thermal Conductance ◽  
Metabolic Heat Production ◽  
Foraging Activity ◽  
Poecile Atricapillus ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Metabolic Heat ◽  
Locomotor Muscles

AbstractWe measured metabolic heat production (H ˙m) of perching and foraging Black-capped Chickadees (Poecile atricapillus) to determine if the heat produced during foraging activity, or exercise thermogenesis, could replace thermoregulatory heat production requirements. H ˙m and activity of chickadees in winter were measured at ambient temperatures (Ta) ranging from −11.5° to 15.5°C. Mean activity amplitude recorded with an activity detector was significantly higher in foraging birds than perching birds. H ˙m did not vary significantly between perching and foraging birds, indicating that heat produced during foraging does substitute for heat produced by shivering for thermoregulation. Evaporative water loss and dry thermal conductance did not vary significantly between perching and foraging chickadees. These results suggest that heat produced from locomotor muscles during foraging activity substitutes for thermoregulatory requirements in glean-and-hang foraging species, such as chickadees, as well as in ground-foraging birds.

Studies of the environmental physiology of tropical merinos

1978 ◽  
Vol 29 (1) ◽  
pp. 161 ◽  
Author(s):  
PS Hopkins ◽  
GI Knights ◽  
AS Le Feuvre
Keyword(s):  
Low Temperature ◽  
Rectal Temperature ◽  
Water Loss ◽  
Heat Dissipation ◽  
Evaporative Water Loss ◽  
Compensatory Mechanisms ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Diurnal Patterns ◽  
Made In

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.

Water Balance of the Camel

1956 ◽  
Vol 185 (1) ◽  
pp. 185-194 ◽  
Author(s):  
Bodil Schmidt-Nielsen ◽  
Knut Schmidt-Nielsen ◽  
T. R. Houpt ◽  
S. A. Jarnum
Keyword(s):  
Body Weight ◽  
Water Loss ◽  
Plasma Concentrations ◽  
The Body ◽  
Evaporative Water Loss ◽  
Weight Changes ◽  
Evaporative Water ◽  
Hot Environment ◽  
Dry Food ◽  
High Degree

Camels ( Camelus dromedarius) were exposed to prolonged periods of water deprivation during winter, spring and summer in the Sahara desert. Determinations were made of: weight changes, water and food intake, urine flow and concentrations, plasma concentrations, etc. It was found that the camel can tolerate a loss of water corresponding to 30% of its body weight even when exposed to the severe desert heat. Other mammals dehydrated in a hot environment may die from circulatory failure already when the water loss involves 12% of the body weight. Unlike many other mammals the camel does not lose its appetite when deprived of water but continues to eat normally until the desiccation becomes very severe. It has a low urine output (0.5–1 l/day when kept on a diet of dates and hay), a low water content in the feces, and, when dehydrated in the summer, a very low evaporative water loss. When offered water the camel drinks in 10 minutes enough water for complete rehydration. The longest period that we kept a camel on dry food without drinking water in the hot summer was 17 days. This camel was not working and it had its protective fur which decreased the heat gain from the environment. It is concluded that the ability of the camel to withstand prolonged dehydration is due to: a) tolerance to an extremely high degree of desiccation of the body and b) low overall water expenditure. Particularly effective as a water conserving mechanism is the low evaporative water loss during dehydration in the summer.

Temperature regulation and cold acclimation in the golden hamster

1965 ◽  
Vol 20 (3) ◽  
pp. 405-410 ◽  
Author(s):  
Hermann Pohl
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Ambient Temperature ◽  
Cold Acclimation ◽  
Heat Production ◽  
Golden Hamster ◽  
Thermal Conductance ◽  
Muscular Activity ◽  
The Body ◽  
Ambient Temperatures

Characteristics of cold acclimation in the golden hamster, Mesocricetus auratus, were 1) higher metabolic rate at -30 C, 2) less shivering when related to ambient temperature or oxygen consumption, and 3) higher differences in body temperature between cardiac area and thoracic subcutaneous tissues at all ambient temperatures tested, indicating changes in tissue insulation. Cold-acclimated hamsters also showed a rise in temperature of the cardiac area when ambient temperature was below 15 C. Changes in heat distribution in cold-acclimated hamsters suggest higher blood flow and heat production in the thoracic part of the body in the cold. The thermal conductance through the thoracic and lumbar muscle areas, however, did not change notably with lowering ambient temperature. Marked differences in thermoregulatory response to cold after cold acclimation were found between two species, the golden hamster and the thirteen-lined ground squirrel, showing greater ability to regulate body temperature in the cold in hamsters. hibernator; oxygen consumption— heat production; body temperature — heat conductance; muscular activity — shivering; thermoregulation Submitted on July 6, 1964

Ecology of Australian chats (Epthianura Gould) season movements, metabolism and ecaporative water loss

1976 ◽  
Vol 24 (3) ◽  
pp. 397 ◽  
Author(s):  
CK Williams ◽  
AR Main
Keyword(s):  
Water Loss ◽  
Arid Regions ◽  
Evaporative Water Loss ◽  
Evaporative Water ◽  
Seasonal Movements ◽  
Ambient Temperatures ◽  
Thermoneutral Zone ◽  
Winter Temperatures ◽  
Summer Temperatures ◽  
Body Heat

The four species of Australian chats differ in their utilization of arid regions. Comparisons were made between the rates of metabolism and evaporative water loss of three species at moderate and high ambient temperatures, after trapping in the field during winter and after acclimation in the laboratory to 22�C and 14�C. When acclimated to winter temperatures the three species had similar rates of metabolism at moderate and high ambient temperatures. The rates of evaporative water loss at moderate temperatures were similar, but at temperatures above the thermoneutral zone the rates were lower in the more xeric than the more mesic species. When acclimated to summer temperatures the more xeric species had lower rates of metabolism and evaporative water loss than the more mesic species at temperatures within and above the thermoneutral zone. Variation in the rates of metabolism and evaporative water loss in field populations was greatest in the most mesic species and least in the most xeric species. Rates of metabolism and evaporative water loss were lower in all species after acclimation to 22�C than after acclimation to 14�C. The rates of metabolism and evaporative water loss tended to be lower than the rates predicted on the basis of body weight. In thermoregulation at high ambient temperatures the more xeric species evaporated relatively less body water in dissipating body heat than the more mesic species, apparently without a greater increase in body temperature. The ability of Australian chats to utilize semiarid and arid regions is explained by distributions and seasonal movements which complement the physiology of evaporative water loss and thermoregulation in a manner that enhances survival at high ambient temperatures.

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