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.

Biophysical constraints on the thermal ecology of dinosaurs

Paleobiology ◽  
1999 ◽  
Vol 25 (3) ◽  
pp. 341-368 ◽  
Author(s):  
Michael P. O'Connor ◽  
Peter Dodson
Keyword(s):  
Blood Flow ◽  
Body Temperature ◽  
Metabolic Rate ◽  
The Body ◽  
Behavioral Thermoregulation ◽  
Seasonal Adjustment ◽  
List Type ◽  
Metabolic Rates ◽  
Body Temperatures ◽  
Precise Control

A physical, model-based approach to body temperatures in dinosaurs allows us to predict what ranges of body temperatures and what thermoregulatory strategies were available to those dinosaurs. We argue that 1.The huge range of body sizes in the dinosaurs likely resulted in very different thermal problems and strategies for animals at either end of this size continuum.2.Body temperatures of the smallest adult dinosaurs and of hatchlings and small juveniles would have been largely insensitive to metabolic rates in the absence of insulation. The smallest animals in which metabolic heating resulted in predicted body temperatures ≥ 2°C above operative temperatures (Te) weigh 10 kg. Body temperature would respond rapidly enough to changes in Te to make behavioral thermoregulation possible.3.Body temperatures of large dinosaurs (>1000 kg) likely were sensitive to both metabolic rate and the delivery of heat to the body surface by blood flow. Our model suggests that they could adjust body temperature by adjusting metabolic rate and blood flow. Behavioral thermoregulation by changing microhabitat selection would likely have been of limited utility because body temperatures would have responded only slowly to changes in Te.4.Endothermic metabolic rates may have put large dinosaurs at risk for overheating unless they had adaptations to shed the heat as necessary. This would have been particularly true for dinosaurs with masses > 10,000 kg, but simulations suggest that for animals as small as 1000 kg in the Tropics and in temperate latitudes during the summer, steady-state body temperatures would have exceeded 40°C. Slow response of body temperatures to changes in Te suggests that use of day-night thermal differences would have buffered dinosaurs from diel warming but would not have lowered body temperatures sufficiently for animals experiencing high mean daily Te.5.Endothermic metabolism and metabolic heating might have been useful for intermediate and large-sized (100–3000 kg) dinosaurs but often in situations that demanded marked seasonal adjustment of metabolic rates and/or precise control of metabolism (and heat-loss mechanisms) as typically seen in endotherms.

Thermal relations of the malle fragon Amphibolurus fordi (Lacertilia : Agamidae)

1974 ◽  
Vol 22 (3) ◽  
pp. 319 ◽  
Author(s):  
HG Cogger
Keyword(s):  
Body Temperature ◽  
Field Study ◽  
New South ◽  
Close Association ◽  
The Body ◽  
Total Effect ◽  
Body Temperatures ◽  
South Wales ◽  
Wide Range ◽  
Thermal Relations

A field study of the thermal relationships of the small agamid lizard A. fordi has been carried out in two areas of mallee in central western New South Wales, where this lizard occurs only in close association with the grass Triodia scariosa. The body temperatures characteristic of various phases in this lizard's die1 cycle have been determined. The behavioural techniques employed to regulate temperature are described; they are similar to those used by a wide range of diurnal heliothermic lizards in other regions. The total effect of these thermoregulatory responses is to maintain an internal thermal environ- ment approaching homoiothermy while the lizard is active. For A. fordi the eccritic body temperature determined from animals in the field is 36.9+-0.16C. Lowering of activity thermal levels occurs in winter, and can be induced at any time by even mild starvation.

Standard metabolic rate and preferred body temperatures in some Australian pythons

1998 ◽  
Vol 46 (4) ◽  
pp. 317 ◽  
Author(s):  
Gavin S. Bedford ◽  
Keith A. Christian
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Thermal Sensitivity ◽  
Standard Metabolic Rate ◽  
Allometric Equations ◽  
Metabolic Rates ◽  
Body Temperatures ◽  
Daily Cycle ◽  
Preferred Body Temperature

Pythons have standard metabolic rates and preferred body temperatures that are lower than those of most other reptiles. This study investigated metabolic rates and preferred body temperatures of seven taxa of Australian pythons. We found that Australian pythons have particularly low metabolic rates when compared with other boid snakes, and that the metabolic rates of the pythons did not change either seasonally or on a daily cycle. Preferred body temperatures do vary seasonally in some species but not in others. Across all species and seasons, the preferred body temperature range was only 4.9˚C. The thermal sensitivity (Q10) of oxygen consumption by pythons conformed to the established range of between 2 and 3. Allometric equations for the pooled python data at each of the experimental temperatures gave an equation exponent of 0.72–0.76, which is similar to previously reported values. By having low preferred body temperatures and low metabolic rates, pythons appear to be able to conserve energy while still maintaining a vigilant ‘sit and wait’ predatory existence. These physiological attributes would allow pythons to maximise the time they can spend ‘sitting and waiting’ in the pursuit of prey.

Body temperature and standard metabolic rate of the female viviparous lizard Eremias multiocellata during reproduction

2012 ◽  
Vol 90 (1) ◽  
pp. 79-84 ◽  
Author(s):  
Feng Yue ◽  
Xiao-Long Tang ◽  
De-Jiu Zhang ◽  
Xue-Feng Yan ◽  
Ying Xin ◽  
...  
Keyword(s):  
Body Temperature ◽  
Metabolic Rate ◽  
Ambient Temperature ◽  
Energy Cost ◽  
Energy Requirement ◽  
Standard Metabolic Rate ◽  
The Body ◽  
Energetic Cost ◽  
Pregnant Females ◽  
Eremias Multiocellata

The body temperature (Tb) and standard metabolic rate (SMR) of female Eremias multiocellata Günther, 1872, a viviparous lizard, were measured at 25, 30, and 35 °C during pregnancy and after parturition to assess energy requirement of reproduction. The results showed that the Tbs of female lizards were slightly higher than actual ambient temperature in the 25 and 30 °C groups, while they were slightly lower than ambient temperature in the 35 °C group. Ambient temperature significantly affected SMR and gestation period of females. Energy requirement was constant in nonpregnant females, whereas it was increased in pregnant females. The maximal estimates of maintenance costs of pregnancy (MCP) were 4.219, 4.220, and 4.448 mg CO2·min–1, which accounted for 19.40%, 14.15%, and 12.32% of the total metabolic rate in the 25, 30, and 35 °C group, respectively. The results indicated the MCP was an important component of total energy cost for the lizard E. multiocellata and the MCP in this lizard incurs a relative fixed energetic cost irrespective of ambient temperature.

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.

THE RELATION BETWEEN HEART RATE AND VAGAL STIMULATION FREQUENCY IN THE RAT AT DIFFERENT BODY TEMPERATURES

1957 ◽  
Vol 35 (1) ◽  
pp. 1153-1164 ◽  
Author(s):  
G. W. Mainwood
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Critical Frequency ◽  
Theoretical Models ◽  
Stimulation Frequency ◽  
The Body ◽  
Body Temperatures ◽  
Regeneration Time ◽  
Reduced Rate ◽  
The Right

The peripheral end of the right vagus was stimulated in acutely vagotomized rats under anaesthesia at different body temperatures. A fairly abrupt increase in the R–R time on the electrocardiogram was observed when a critical stimulation frequency was reached. At a body temperature of 35 °C. the critical frequency is 10 per second or more. On lowering of the body temperature to 28 °C. the critical frequency is greatly reduced so that considerable slowing may be elicited at frequencies as low as one to five per second. Possible theoretical models to account for the critical frequency and its variation with temperature are considered. The temperature effect is too great to be accounted for either on the basis of the increased number of impulses which reach the heart per cardiac cycle, or the reduced rate of cholinesterase activity. The theory most consistent with the results is that each vagal impulse liberates or inactivates a substance, the concentration of which varies directly with heart rate. The interimpulse interval at the critical frequency would then represent the regeneration time of this substance. The temperature coefficient of the regeneration process appears to be about 3.3 per 10 °C.

scholarly journals Study on the Effect of the Ambient Temperature toward the Quality of Sleep

2017 ◽  
Vol 7 (6) ◽  
pp. 2986
Author(s):  
Wira Hidayat bin Mohd Saad ◽  
Khoo Chin Wuen ◽  
Masrullizam bin Mat Ibrahim ◽  
Nor Hashimah Binti Mohd Saad ◽  
Syafeeza Binti Ahmad Radz ◽  
...  
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Ambient Temperature ◽  
Body Condition ◽  
Body Movement ◽  
The Body ◽  
Quality Of Sleep ◽  
Ambient Temperatures ◽  
The Right

Getting enough sleep at the right times can help in improving quality of life and protect mental and physical health. This study proposes a portable sleep monitoring device to determine the relationship between the ambient temperature and quality of sleep. Body condition parameter such as heart rate, body temperature and body movement was used to determine quality of sleep. All readings will be log into database so that users can review back and hence analyze quality of sleep. The functionality of the overall system is designed for a better experience with a very minimal intervention to the user. The simple test on the body condition (body temperature and heart rate) while asleep with several different ambient temperatures are varied and the result shows that someone has a better sleep for the temperature range of 23 to 28 degree Celsius. This can prove by lower body temperature and lower heart rate.

THE RELATION BETWEEN HEART RATE AND VAGAL STIMULATION FREQUENCY IN THE RAT AT DIFFERENT BODY TEMPERATURES

1957 ◽  
Vol 35 (12) ◽  
pp. 1153-1164 ◽  
Author(s):  
G. W. Mainwood
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Critical Frequency ◽  
Theoretical Models ◽  
Stimulation Frequency ◽  
The Body ◽  
Body Temperatures ◽  
Regeneration Time ◽  
Reduced Rate ◽  
The Right

The peripheral end of the right vagus was stimulated in acutely vagotomized rats under anaesthesia at different body temperatures. A fairly abrupt increase in the R–R time on the electrocardiogram was observed when a critical stimulation frequency was reached. At a body temperature of 35 °C. the critical frequency is 10 per second or more. On lowering of the body temperature to 28 °C. the critical frequency is greatly reduced so that considerable slowing may be elicited at frequencies as low as one to five per second. Possible theoretical models to account for the critical frequency and its variation with temperature are considered. The temperature effect is too great to be accounted for either on the basis of the increased number of impulses which reach the heart per cardiac cycle, or the reduced rate of cholinesterase activity. The theory most consistent with the results is that each vagal impulse liberates or inactivates a substance, the concentration of which varies directly with heart rate. The interimpulse interval at the critical frequency would then represent the regeneration time of this substance. The temperature coefficient of the regeneration process appears to be about 3.3 per 10 °C.

Hypoxic metabolic response of the golden-mantled ground squirrel

2001 ◽  
Vol 91 (2) ◽  
pp. 603-612 ◽  
Author(s):  
Renata C. H. Barros ◽  
Mary E. Zimmer ◽  
Luiz G. S. Branco ◽  
William K. Milsom
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Small Mammals ◽  
Ground Squirrel ◽  
Metabolic Response ◽  
Ground Squirrels ◽  
Metabolic Rates ◽  
The Relationship ◽  
Primary Strategy

We examined the magnitude of the hypoxic metabolic response in golden-mantled ground squirrels to determine whether the shift in thermoregulatory set point (Tset) and subsequent fall in body temperature (Tb) and metabolic rate observed in small mammals were greater in a species that routinely experiences hypoxic burrows and hibernates. We measured the effects of changing ambient temperature (Ta; 6–29°C) on metabolism (O2 consumption and CO2 production), Tb, ventilation, and heart rate in normoxia and hypoxia (7% O2). The magnitude of the hypoxia-induced falls in Tb and metabolism of the squirrels was larger than that of other rodents. Metabolic rate was not simply suppressed but was regulated to assist the initial fall in Tb and then acted to slow this fall and stabilize Tb at a new, lower level. When Ta was reduced during 7% O2, animals were able to maintain or elevate their metabolic rates, suggesting that O2 was not limiting. The slope of the relationship between temperature-corrected O2 consumption and Taextrapolated to a Tset in hypoxia equals the actual Tb. The data suggest that Tset was proportionately related to Ta in hypoxia and that there was a shift from increasing ventilation to increasing O2extraction as the primary strategy employed to meet increasing metabolic demands under hypoxia. The animals were neither hypothermic nor hypometabolic, as Tb and metabolic rate appeared to be tightly regulated at new but lower levels as a result of a coordinated hypoxic metabolic response.

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.

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