scholarly journals Body Temperatures in Some Australian Mammals II.Peramelidae

1962 ◽  
Vol 15 (2) ◽  
pp. 386 ◽  
Author(s):  
PR Morrison
Keyword(s):  
Body Temperature ◽  
Ambient Temperature ◽  
Active Phase ◽  
Temperature Measurements ◽  
Temperature Cycle ◽  
Body Temperatures ◽  
Ambient Temperatures ◽  
Diurnal Temperature

Body temperature measurements on the short-nosed bandicoot (Thylacis obeaulus) have shown a nocturnal cycle with a range of 1� 2�C and a short active phase at 2200-0400 hr. The bilby or rabbit bandicoot (Macrotis lagoti8) had a sharply defined temperature cycle, with a range of almost 3�C after several months of captivity, during which the day-time resting temperature was progressively lowered from 36� 4 to 34� 2�C. Forced activity raised the diurnal temperature substantially but not to the nocturnal level. Forced activity did not raise the nocturnal level which was similar in the two species (37' O�C). Both species could regulate effectively at an ambient temperature of 5�C, but only Thylaci8 showed regulation at ambient temperatures of between 30 and 40�C.

Diurnal body temperature variations and hibernation in the birchmouse, Sicista betulina

1959 ◽  
Vol 196 (6) ◽  
pp. 1200-1204 ◽  
Author(s):  
Kjell Johansen ◽  
John Krog
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Respiratory Rate ◽  
Maximal Activity ◽  
Temperature Cycle ◽  
Body Temperatures ◽  
Temperature Variations ◽  
Ambient Temperatures ◽  
The Awakening ◽  
Compensatory Increase

Body temperatures, oxygen consumption and electrocardiograms were recorded in the birchmouse. The diurnal body temperature cycle ranged from 5° to 18°C during a regular 24-hour sequence. The highest body temperatures (37–38°C) are present around midnight, coinciding with the time of maximal activity. Body temperatures and oxygen consumption were studied at various ambient temperatures. With decreasing temperature the oxygen consumption commonly followed two successive patterns: first, a period of compensatory increase after which body temperature and oxygen consumption decreased; the compensation lasted from 5 minutes to 4 hours. At low ambient temperatures the animals went into a state of dormancy similar to seasonal hibernation in other mammals. The reduction in heart and respiratory rate as well as in oxygen consumption and body temperature confirmed those values reported earlier. Arousal from hibernation in the birchmouse is unique in the great speed of reaction with which the awakening takes place. Body temperature may increase as much as 1°C/min. and, within a period of 30 minutes, the oxygen consumption may increase 25 times.

Ambient temperature effects on physiological traits of white-tailed deer

1975 ◽  
Vol 53 (6) ◽  
pp. 679-685 ◽  
Author(s):  
J. B. Holter ◽  
W. E. Urban Jr. ◽  
H. H. Hayes ◽  
H. Silver ◽  
H. R. Skutt
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Energy Expenditure ◽  
Ambient Temperature ◽  
Temperature Effects ◽  
Temperature Changes ◽  
Wind Chill ◽  
Ambient Temperatures ◽  
Energy Equilibrium ◽  
Body Energy

Six adult white-tailed deer (Odocoileus virginianus borealis) were exposed to 165 periods of 12 consecutive hours of controlled constant ambient temperature in an indirect respiration calorimeter. Temperatures among periods varied from 38 to 0 (summer) or to −20C (fall, winter, spring). Traits measured were energy expenditure (metabolic rate), proportion of time spent standing, heart rate, and body temperature, the latter two using telemetry. The deer used body posture extensively as a means of maintaining body energy equilibrium. Energy expenditure was increased at low ambient temperature to combat cold and to maintain relatively constant body temperature. Changes in heart rate paralleled changes in energy expenditure. In a limited number of comparisons, slight wind chill was combatted through behavioral means with no effect on energy expenditure. The reaction of deer to varying ambient temperatures was not the same in all seasons of the year.

Body temperature regulation and oxygen consumption in young chicks fed thyroid hormone

1991 ◽  
Vol 69 (7) ◽  
pp. 1842-1847 ◽  
Author(s):  
Gregory K. Snyder ◽  
Joseph R. Coelho ◽  
Dalan R. Jensen
Keyword(s):  
Oxygen Consumption ◽  
Thyroid Hormone ◽  
Body Temperature ◽  
Ambient Temperature ◽  
Cold Exposure ◽  
Elevated Serum ◽  
Body Temperatures ◽  
Serum Thyroid Hormone ◽  
Regulate Body Temperature ◽  
Young Chicks

In chicks the ability to regulate body temperature to adult levels develops during the first 2 weeks of life. We examined whether the ability of young chicks to regulate body temperature is increased by elevated levels of the thyroid hormone 3,3′5-triiodothyronine. By 13 days following hatch, body temperatures of chicks were not significantly different from those expected for adult birds. Furthermore, at an ambient temperature of 10 °C, 13-day-old control chicks were able to maintain body temperature, and elevated serum thyroid hormone levels did not increase rates of oxygen consumption or body temperature above control values. Six-day-old chicks had body temperatures that were significantly lower than those of the 13-day-old chicks and were not able to regulate body temperature when exposed to an ambient temperature of 10 °C. On the other hand, 6-day-old chicks with elevated serum thyroid hormone had significantly higher rates of oxygen consumption than 6-day-old control chicks, and were able to maintain constant body temperatures during cold exposure. The increased oxygen consumption rates and improved ability to regulate body temperature during cold exposure were correlated with increased citrate synthase activity in skeletal muscle. Our results support the argument that thyroid hormones play an important role in the development of thermoregulatory ability in neonate birds by stimulating enzyme activities associated with aerobic metabolism.

Parasympathetic influence on heart rate in euthermic and hibernating ground squirrels.

1995 ◽  
Vol 198 (4) ◽  
pp. 931-937 ◽  
Author(s):  
M B Harris ◽  
W K Milsom
Keyword(s):  
Heart Rate ◽  
Ambient Temperature ◽  
Parasympathetic Nervous System ◽  
Ground Squirrels ◽  
Relative Role ◽  
Body Temperatures ◽  
Inotropic Effects ◽  
Ambient Temperatures ◽  
Isolated Hearts ◽  
C 32

The relative role of the parasympathetic nervous system during deep hibernation is enigmatic. Conflicting hypotheses exist, and both sides draw support from investigations of vagal influence on the heart. Recent studies have shown cardiac chronotropic and inotropic effects of parasympathetic stimulation and inhibition in isolated hearts and anesthetized animals at hibernating body temperatures. No studies, however, have demonstrated such occurrences in undisturbed deeply hibernating animals. The present study documents respiratory-related alterations in heart rate during euthermia and hibernation at ambient temperatures of 15, 10 and 5 degrees C mediated by parasympathetic influence. During quiet wakefulness, euthermic squirrels breathed continuously and exhibited a 29% acceleration in heart rate during inspiration. During deep undisturbed hibernation, at 15, 10 and 5 degrees C ambient temperature, animals exhibited an episodic breathing pattern and body temperatures were slightly above ambient temperature. At each temperature, heart rate during the respiratory episode was greater than that during the apnea. The magnitude of this ventilatory tachycardia decreased with ambient temperature, being 108% at 15 degrees C, 32% at 10 degrees C and 11.5% at 5 degrees C. Animals exposed to 3% CO2 at 5 degrees C, which significantly increased ventilation, still exhibited an 11.7% increase in heart rate during breathing. Thus, the magnitude of the ventilation tachycardia was independent of the level of ventilation, at least over the range studied. Inhibition of vagus nerve conduction at 5 degrees C was achieved using localized nerve block. This led to an increase in apneic heart rate and abolished the ventilatory tachycardia.(ABSTRACT TRUNCATED AT 250 WORDS)

Thermal homeostasis in rats after intrahypothalamic injections of 6-hyroxydopamine

1976 ◽  
Vol 230 (4) ◽  
pp. 932-939 ◽  
Author(s):  
JG Van Zoeren ◽  
EM Stricker
Keyword(s):  
Body Temperature ◽  
Ambient Temperature ◽  
Thermal Balance ◽  
Local Injection ◽  
Noradrenergic Neurons ◽  
Body Temperatures ◽  
Hypothalamic Region ◽  
Electrolytic Lesions ◽  
Noradrenergic Fibers ◽  
Effector Mechanisms

Specific destruction of at least 90% of the noradrenergic neurons in the preoptic/anterior hypothalamic region (PO/AH) by local injection of 9-hyroxydopamine (6-HDA) did not disrupt thermoregulation by rats either in the heat or the cold. Examination of the multiple effector mechanisms suggested that thermal balance was maintained in a normal fashion, and that compensatory adjustments did not conceal individual dysfunctions. In contrast with the ineffectual 6-HDA lesions of the PO/AH were the outstanding impairments seen in rats following electrolytic lesions of this area. All the latter animals became severely hyperthermic during the 1st h of exposure to an ambient temperature of 40 degrees C, and half of them were additionally unable to maintain body temperatures when exposed to an ambient temperature of 6 degrees C. The electrolytic lesions reduced norepinephrine levels in the PO/AH, but the 50-70% depletions were substantially smaller than those found in 6-HDA-treated rats. These results raise new doubts about whether central noradrenergic fibers have an important role in the regulation of body temperature by rats.

Studies on the adaptability of three breeds of sheep to a tropical environment modified by altitude II. Responses in body, skin and coat temperatures, cardio-respiratory frequencies and rate of moisture secretion of ewes to the diurnal fluctuation in ambient temperature during the hottest part of the year

1960 ◽  
Vol 55 (3) ◽  
pp. 295-302 ◽  
Author(s):  
R. B. Symington
Keyword(s):  
Body Temperature ◽  
Ambient Temperature ◽  
Skin Temperature ◽  
Skin Surface ◽  
Diurnal Fluctuation ◽  
Body Temperatures ◽  
Solar Insolation ◽  
Air Temperatures ◽  
Insensible Perspiration ◽  
Artificial Heat

Responses in body, skin and coat temperatures, cardio-respiratory frequencies and rate of moisture secretion of ewes of three breeds to the diurnal fluctuation in ambient temperature were recorded in the presence and absence of drinking water during the hottest part of the Rhodesian year.1. At 7.0 a.m. body temperatures were: Merino 102·8° F.; Persian 102·2° F. and Native 101·5° F. Between 7·0 a.m. and 1·0 p.m. body temperature rose almost equally in Persians and Natives and fell slightly in Merinos. Change in body temperature between 7.0 a.m. and 1.0 p.m. was not affected significantly by availability of water nor age of ewe, but varied with type of thermal burden (i.e. solar insolation only v. solar insolation plus artificial heat) when water was not available. Although air temperature fell towards late afternoon body temperature of Merinos and Natives rose appreciably, that of Persians only slightly.2. At 7·0 a.m. respiratory rates were (cyc./min.): Merino 59·6; Persian 43·0; Native 29·9. Increase in rate of respiration was the main thermolytic mechanism in all breeds. Merinos had a lower threshold of respiratory response to rising ambient temperature than either hair breed but increase in rate of respiration between 7.0 a.m. and 1.0 p.m. did not differ significantly with breed or age.3. No breed appeared to use the peripheral blood system in thermoregulation. Cardio-frequency, as a measure of this blood flow, remained almost constant with a slight tendency to fall with rise in ambient temperature.4. In all breeds skin temperature was related to ambient and body temperatures; consequently the diurnal fluctuation in skin temperature differed in wool and hair breeds. When thermal burden was greatest Merino skin temperature fell, that of hair breeds did not.Except at 11.0 a.m. there was a gradient between rectal, skin and air temperatures. Direct elimination of heat was thus possible for 23 hr. each day.5. In hair breeds moisture secretion depended on insensible perspiration; consequently, rate of moisture secretion changed with body and air temperatures. In Merinos moisture for skin surface evaporation was provided by sensible and insensible perspiration. Natives may be able to sweat at temperatures higher than those recorded but it is unlikely Persians have a sweating mechanism.6. In all breeds coat temperature was related closely to ambient temperature and changes in solar conditions evoked immediate response in coat temperature. Merino fleece apparently stabilized skin temperature whereas Persian and Native hair did not.

scholarly journals Heart rate reveals torpor at high body temperatures in lowland tropical free-tailed bats

2017 ◽  
Vol 4 (12) ◽  
pp. 171359 ◽  
Author(s):  
M. Teague O'Mara ◽  
Sebastian Rikker ◽  
Martin Wikelski ◽  
Andries Ter Maat ◽  
Henry S. Pollock ◽  
...  
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Ambient Temperature ◽  
The Body ◽  
Metabolic Rates ◽  
Body Temperatures ◽  
Wide Range ◽  
Save Energy ◽  
Molossus Molossus

Reduction in metabolic rate and body temperature is a common strategy for small endotherms to save energy. The daily reduction in metabolic rate and heterothermy, or torpor, is particularly pronounced in regions with a large variation in daily ambient temperature. This applies most strongly in temperate bat species (order Chiroptera), but it is less clear how tropical bats save energy if ambient temperatures remain high. However, many subtropical and tropical species use some daily heterothermy on cool days. We recorded the heart rate and the body temperature of free-ranging Pallas' mastiff bats ( Molossus molossus ) in Gamboa, Panamá, and showed that these individuals have low field metabolic rates across a wide range of body temperatures that conform to high ambient temperature. Importantly, low metabolic rates in controlled respirometry trials were best predicted by heart rate, and not body temperature . Molossus molossus enter torpor-like states characterized by low metabolic rate and heart rates at body temperatures of 32°C, and thermoconform across a range of temperatures. Flexible metabolic strategies may be far more common in tropical endotherms than currently known.

scholarly journals Thermal biology of Amphisbaena munoai (Squamata: Amphisbaenidae)

2018 ◽  
Vol 35 ◽  
pp. 1-9 ◽  
Author(s):  
Nathalia Rocha Matias ◽  
Laura Verrastro
Keyword(s):  
Body Temperature ◽  
Ambient Temperature ◽  
Thermal Environment ◽  
Rio Grande ◽  
The Body ◽  
Rio Grande Do Sul ◽  
Body Temperatures ◽  
Physiological Mechanisms ◽  
Thermal Biology ◽  
The Relationship

Studies on the thermal biology of fossorial reptiles that examine the relationship between the body temperature and thermal environment are needed to determine the extent of their thermoregulation abilities. This study assessed the thermal biology of Amphisbaena munoai Klappenbach, 1969 in the rocky fields of the Rio Grande do Sul and in the laboratory. The body temperature of most individuals was between 24 and 30 °C, both in the field (n = 81) and laboratory (n = 19). More individuals were caught in winter (n = 55) and spring (n = 60) than in summer (n = 25) and fall (n = 45), and in spring, individuals showed similar nocturnal and diurnal activities. In the laboratory, we found individuals with body temperatures up to 5 °C higher than the ambient temperature (n = 4), suggesting that some physiological mechanisms participate in the thermoregulation of these animals. Amphisbaena munoai is a thigmothermic species that is capable of actively regulating its temperature by selecting microhabitats such that its various activities occur within an ideal temperature range. This study is the first to evaluate the effect of seasonality and diurnal and nocturnal variations on the thermoregulation of an amphisbaenid.

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

Differential effects of hypoxia on sleep of warm- and cold-acclimated rats

1987 ◽  
Vol 63 (6) ◽  
pp. 2189-2194 ◽  
Author(s):  
M. J. Pollard ◽  
D. Megirian ◽  
J. H. Sherrey
Keyword(s):  
Body Temperature ◽  
Ambient Temperature ◽  
Neural Mechanism ◽  
Body Temperatures ◽  
Deep Body Temperature ◽  
Neutral Temperature ◽  
State Changes ◽  
Different Levels ◽  
Deep Body ◽  
Maximum Minimum

We studied the effect of different levels of hypoxia (10, 12 or 13, 15, and 18% O2) on the sleep-waking pattern (SWP) and the maximum-minimum core temperature of warm-acclimated (WA) and cold-acclimated (CA) rats at their neutral temperature, 29 degrees C. Whereas the SWP of WA rats showed a trend toward increasing disruption as the degree of hypoxia increased, CA rats exhibited no such trend. The effect was chiefly on the frequency of state changes and less on epoch durations. The SWP of WA rats was more vulnerable to hypoxia than that of CA rats. Maximum and minimum body temperatures of WA and CA rats were not significantly affected by O2 lack down to 10% inspired O2. We conclude that in the rat 1) hypoxia primarily affects the neural mechanism that governs the frequency of changes in sleep-waking states; 2) the extent of alterations in SWP's depends on the ambient temperature to which the rats are acclimated; and 3) hypoxia does not significantly affect deep body temperature at the animal's neutral temperature.

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