THE INFLUENCE OF CLIMATE ON METABOLIC AND THERMAL RESPONSES OF INFANT CARIBOU

1961 ◽  
Vol 39 (6) ◽  
pp. 845-856 ◽  
Author(s):  
J. S. Hart ◽  
O. Heroux ◽  
W. H. Cottle ◽  
C. A. Mills
Keyword(s):  
Metabolic Rate ◽  
Heat Loss ◽  
Temperature Regulation ◽  
Weather Conditions ◽  
Wind Chill ◽  
Prediction Of Mortality ◽  
Cold Wind

Metabolic and thermal responses of infant caribou to climate were measured during the June calving period on the barrens in the area of Mosquito Lake and Beverly Lake, N.W.T. It was found that temperature regulation was well established at birth and that the calves were very sensitive metabolically to cold, wind, and precipitation. The metabolic rate was doubled by a lowering of temperature to about 0 °C, but cold combined with wind and precipitation elevated the metabolic rate to over five times the resting value. Calves which were exposed without protection to such conditions eventually became hypothermic and died. Weather conditions during storms on the barrens are sufficiently severe to produce some mortality in animals exposed without protection. The possibilities for prediction of mortality from wind chill values and estimated fur heat loss are discussed.

Temperature regulation in the new-born lamb. IV. The effect of wind and evaporation of water from the coat on metabolic rate and body temperature

1962 ◽  
Vol 13 (1) ◽  
pp. 82 ◽  
Author(s):  
G Alexander
Keyword(s):  
Metabolic Rate ◽  
Heat Loss ◽  
Heat Production ◽  
Temperature Regulation ◽  
Tap Water ◽  
High Heat ◽  
Cooling Efficiency ◽  
Experimental Conditions ◽  
Ambient Temperatures ◽  
New Born

The study of temperature regulation in new-born lambs has been extended from dry lambs in "still air" at various ambient temperatures to dry lambs in a wind of 550 cm sec-l, and to lambs whose coats are drying. Exposure to wind resulted in an increased slope of the line relating heat production to ambient temperature, but under the experimental conditions evaporation of water from the coat added approximately the same increment at all ambient temperatures. The effects of wind and evaporation at any one temperature appeared additive. The heat loss from naturally wet new-born lambs less than 1 hr old, in a wind, was greater than in slightly older lambs wetted with tap water. Lambs with hairy coats were able to conserve heat more readily than lambs with fine coats. The cooling efficiency of evaporation from the coat was about 25%. The elevation in temperature of the extremities which follows feeding and persists under conditions of moderate heat loss, appears to be almost abolished under conditions of high heat loss. During the studies on drying lambs, beat loss in many lambs exceeded heat production, and rectal temperature fell, which thus indicated the maximum possible heat production (summit metabolic rate) of which lambs are capable. Lambs from ewes on low or medium levels of feeding during pregnancy cooled more readily than lambs from well-fed ewes.

The Mechanisms and Energetics of Honeybee Swarm Temperature Regulation

1981 ◽  
Vol 91 (1) ◽  
pp. 25-55
Author(s):  
BERND HEINRICH
Keyword(s):  
Metabolic Rate ◽  
Heat Loss ◽  
Temperature Regulation ◽  
Resting Metabolic Rate ◽  
Primary Role ◽  
Set Point ◽  
Ambient Temperatures ◽  
Thermal Environments ◽  
Lower Temperature

1. Free (active) honeybee swarms regulated their core temperature (Tc) generally within 1 °C of 35 °C. They maintained the same temperature around freshly built honeycomb, and in the brood nest of the hive, from ambient temperatures of between at least 1 and 25 °C. Captive (inactive) swarms in the laboratory often allowed Tc to decline below 35 °C. 2. The temperature of the swarm mantle (Tm) varied with the general activity of the swarm as well as with ambient temperature (TA), but in captive swarms (and sometimes at night in free swarms), Tm was generally held above 17 °C, even at TA < 5 °C. 3. Within the swarm, temperatures varied between 36 °C, an upper temperature set-point, and 17 °C, a lower temperature set-point. 4. Before swarm take-off, all temperature gradients in the swarm were abolished and Tm equalled Tc. 5. The regulated Tc and Tm were unrelated to size and passive cooling rates in swarms ranging from 1000 to 30000 bees. 6. The weight-specific metabolic rate of swarms was correlated with TA and Tc, but relatively little affected by swarm size. 7. Bees on the mantle experiencing low temperatures pushed inward, thus contracting the mantle, diminishing the mantle porosity, and filling interior passageways. As a result, their own rate of heat loss, as well as that from the swarm core, decreased. 8. In large tightly clumped swarms, even at TA < 5 °C, the resting metabolic rate of the bees in the swarm core was more than sufficient to maintain Tc at 35 °C or above. The active thermoregulatory metabolism was due to the bees on the swarm mantle. 9. There was little physical exchange of bees between core and mantle at low (< 5 °C) TA. In addition, there was no apparent chemical or acoustic communication between the bees in the swarm mantle that are subjected to the changes of the thermal environments and the bees in the swarm interior that constantly experience 35 °C regardless of TA. 10. The data are summarized in a model of Tc control indicating a primary role of the mantle bees in controlling heat production and heat loss. 11. The possible ecological significance of swarm temperature regulation is discussed.

Accidental Hypothermia

PEDIATRICS ◽  
1979 ◽  
Vol 63 (6) ◽  
pp. 926-928
Keyword(s):  
Heat Loss ◽  
Heat Production ◽  
Weather Conditions ◽  
Accidental Hypothermia ◽  
Good Judgment ◽  
Hand Coordination ◽  
Body Heat ◽  
Unfavorable Weather

Pediatricians may be able to bring the dangers of accidental hypothermia to the attention of their patients at the time of a sports, camp, or college "physical." People who spend time outdoors must learn to recognize hypothermia-producing weather and water; to know that shivering indicates heat loss exceeding available insulation and body heat production; and to understand that loss of good judgment and hand coordination soon follow uncontrollable shivering. They must not go into areas in which, without proper gear, unfavorable weather conditions or dangerous water may develop, and they must understand that most tragedies from cold result from failure to make camp or to return to safety when weather conditions become unfavorable.

Interaction of central and peripheral factors in physiological temperature regulation

1961 ◽  
Vol 200 (3) ◽  
pp. 572-580 ◽  
Author(s):  
M. M. Fusco ◽  
J. D. Hardy ◽  
H. T. Hammel
Keyword(s):  
Heat Loss ◽  
Core Temperature ◽  
Heat Production ◽  
Temperature Regulation ◽  
Physiological Temperature ◽  
Warm Environment ◽  
Quantitative Estimates ◽  
Cool Environment ◽  
Localized Heating ◽  
Environmental Temperatures

To evaluate the relative importance of central and peripheral factors in physiological temperature regulation, calorimetric measurements of thermal and metabolic responses in the unanesthetized dog to localized heating of the supraoptic and preoptic regions were made at various environmental temperatures. At all temperatures, heating the hypothalamus caused an imbalance in the over-all heat exchange, and lowered core temperature by 0.8°–1.0°C. In a neutral environment, this was effected by a 30–40% depression of the resting rate of heat production. In a cool environment, heating inhibited shivering so that heat production, relative to heat loss, was low. In a warm environment, vigorous panting and vasodilatation were elicited, thereby increasing heat loss. On cessation of heating, shivering occurred in response to the lowered core temperature, but differed in intensity depending upon the peripheral thermal drive. Reapplication of heating suppressed shivering in all cases. From these data some quantitative estimates were made of the sensitivity of the hypothalamic thermoregulatory ‘centers’, and of the interaction and relative contributions of central and peripheral control.

Body Weight and the Energetics of Temperature Regulation: a Re-Examination

1972 ◽  
Vol 56 (3) ◽  
pp. 775-780
Author(s):  
WILLIAM A. CALDER ◽  
JAMES R. KING
Keyword(s):  
Body Weight ◽  
Heat Loss ◽  
Temperature Regulation ◽  
Theoretical Treatment ◽  
Newtonian Model

The Newtonian model of heat loss from homoiotherms may remain as a useful approximation of thermoregulatory relationships and as a practical basis for comparison of species from laboratory responses. The validity of this, however, has not been established or furthered by the theoretical treatment that is re-analysed in this paper.

Thermoregulation of African and European Honeybees during Foraging, Attack, and Hive Exits and Returns

1979 ◽  
Vol 80 (1) ◽  
pp. 217-229 ◽  
Author(s):  
HEINRICH BERND
Keyword(s):  
Metabolic Rate ◽  
Ambient Temperature ◽  
Heat Loss ◽  
Warm Up ◽  
Ambient Temperatures ◽  
Thoracic Temperature

1. While foraging, attacking, or leaving or returning to their hives, both the African and European honeybees maintained their thoracic temperature at 30 °C or above, independent of ambient temperature from 7 to 23 °C (in shade). 2. Thoracic temperatures were not significantly different between African and European bees. 3. Thoracic temperatures were significantly different during different activities. Average thoracic temperatures (at ambient temperatures of 8–23 °C) were lowest (30 °C) in bees turning to the hive. They were 31–32 °C during foraging, and 36–38 °C in bees leaving the hive, and in those attacking. The bees thus warm up above their temperature in the hive (32 °C) before leaving the colony. 4. In the laboratory the bees (European) did not maintain the minimum thoracic temperature for continuous flight (27 °C) at 10 °C. When forced to remain in continuous flight for at least 2 min, thoracic temperature averaged 15 °C above ambient temperature from 15 to 25 °C, and was regulated only at high ambient temperatures (30–40 °C). 5. At ambient temperatures > 25 °C, the bees heated up during return to the hive, attack and foraging above the thoracic temperatures they regulated at low ambient temperatures to near the temperatures they regulated during continuous flight. 6. In both African and European bees, attack behaviour and high thoracic temperature are correlated. 7. The data suggest that the bees regulate thoracic temperature by both behavioural and physiological means. It can be inferred that the African bees have a higher metabolic rate than the European, but their smaller size, which facilitates more rapid heat loss, results in similar thoracic temperatures.

Early Warning System and Adaptation Advice to Reduce Human Health Consequences of Extreme Weather Conditions and Air Pollution

2015 ◽  
pp. 265-301 ◽  
Author(s):  
Dragan Bogdanović ◽  
Konstansa Lazarević
Keyword(s):  
Air Pollution ◽  
General Population ◽  
Information Service ◽  
Weather Conditions ◽  
Extreme Weather ◽  
Internet Service ◽  
Wind Chill ◽  
The Republic ◽  
Index Value ◽  
Sensitive Population

The authors developed a multi-site Internet service to provide the public with real time information about local weather and air quality, how they may affect health, and how general population and different sensitive population groups can protect their health during periods of extreme weather conditions or increased air pollution levels. The information service is based on data obtained from the Republic Hydrometeorological Service of Serbia and Serbian Environment Protection Agency. Health warnings and recommendations are given separately for each AIQ and heat index or wind chill index value, for each sensitive population group, as well as for the general population. The project is currently implemented on the website of the Institute of Occupational Health Niš and will be offered to other healthcare institutions in Serbia. Evaluation of the system should enable redefinition of heat and wind chill indices and air pollution threshold values if necessary. This chapter explores the service.

scholarly journals Approaches for testing hypotheses for the hypometric scaling of aerobic metabolic rate in animals

2018 ◽  
Vol 315 (5) ◽  
pp. R879-R894 ◽  
Author(s):  
Jon F. Harrison
Keyword(s):  
Metabolic Rate ◽  
Heat Loss ◽  
Heat Dissipation ◽  
Morphological Properties ◽  
Compensatory Responses ◽  
Size Dependent ◽  
Extant Species ◽  
Show Evidence ◽  
Selection For ◽  
Interspecific Comparisons

Hypometric scaling of aerobic metabolism [larger organisms have lower mass-specific metabolic rates (MR/g)] is nearly universal for interspecific comparisons among animals, yet we lack an agreed upon explanation for this pattern. If physiological constraints on the function of larger animals occur and limit MR/g, these should be observable as direct constraints on animals of extant species and/or as evolved responses to compensate for the proposed constraint. There is evidence for direct constraints and compensatory responses to O2 supply constraint in skin-breathing animals, but not in vertebrates with gas-exchange organs. The duration of food retention in the gut is longer for larger birds and mammals, consistent with a direct constraint on nutrient uptake across the gut wall, but there is little evidence for evolving compensatory responses to gut transport constraints in larger animals. Larger placental mammals (but not marsupials or birds) show evidence of greater challenges with heat dissipation, but there is little evidence for compensatory adaptations to enhance heat loss in larger endotherms, suggesting that metabolic rate (MR) more generally balances heat loss for thermoregulation in endotherms. Size-dependent patterns in many molecular, physiological, and morphological properties are consistent with size-dependent natural selection, such as stronger selection for neurolocomotor performance and growth rate in smaller animals and stronger selection for safety and longevity in larger animals. Hypometric scaling of MR very likely arises from different mechanisms in different taxa and conditions, consistent with the diversity of scaling slopes for MR.

scholarly journals Do small precocial birds enter torpor to conserve energy during development?

2020 ◽  
Vol 223 (21) ◽  
pp. jeb231761
Author(s):  
Yaara Aharon-Rotman ◽  
Gerhard Körtner ◽  
Chris B. Wacker ◽  
Fritz Geiser
Keyword(s):  
Body Temperature ◽  
Metabolic Rate ◽  
Surface Temperature ◽  
Heat Loss ◽  
Body Mass ◽  
Infrared Thermometer ◽  
Common Strategy ◽  
Energy Conserving ◽  
Altricial Birds ◽  
Precocial Birds

ABSTRACTPrecocial birds hatch feathered and mobile, but when they become fully endothermic soon after hatching, their heat loss is high and they may become energy depleted. These chicks could benefit from using energy-conserving torpor, which is characterised by controlled reductions of metabolism and body temperature (Tb). We investigated at what age the precocial king quail Coturnix chinensis can defend a high Tb under a mild thermal challenge and whether they can express torpor soon after achieving endothermy to overcome energetic and thermal challenges. Measurements of surface temperature (Ts) using an infrared thermometer showed that king quail chicks are partially endothermic at 2–10 days, but can defend high Tb at a body mass of ∼13 g. Two chicks expressed shallow nocturnal torpor at 14 and 17 days for 4–5 h with a reduction of metabolism by >40% and another approached the torpor threshold. Although chicks were able to rewarm endogenously from the first torpor bout, metabolism and Ts decreased again by the end of the night, but they rewarmed passively when removed from the chamber. The total metabolic rate increased with body mass. All chicks measured showed a greater reduction of nocturnal metabolism than previously reported in quails. Our data show that shallow torpor can be expressed during the early postnatal phase of quails, when thermoregulatory efficiency is still developing, but heat loss is high. We suggest that torpor may be a common strategy for overcoming challenging conditions during development in small precocial and not only altricial birds.

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