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.

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.

The effects of body size and temperature on metabolic rate of organisms

1983 ◽  
Vol 61 (2) ◽  
pp. 281-288 ◽  
Author(s):  
W. Richard Robinson ◽  
Robert Henry Peters ◽  
Jess Zimmermann
Keyword(s):  
Oxygen Consumption ◽  
Body Size ◽  
Metabolic Rate ◽  
Standard Metabolic Rate ◽  
Published Data ◽  
Metabolic Rates ◽  
Regression Analyses ◽  
Free Living ◽  
Lower Vertebrates ◽  
Rate Of Oxygen Consumption

Multiple regression analyses of previously published data were performed to describe the effect of variations in body mass (M, in grams) and temperature (t, in degrees Celsius) on the rate of oxygen consumption ([Formula: see text], in millilitres O2 per gram per hour). For homeotherms and poikilotherms, the resultant equations describing standard metabolic rate are [Formula: see text] and [Formula: see text], respectively. The metabolic rate of unicells was described by [Formula: see text], although the temperature term was not statistically significant. When solved at 39 °C, the homeotherm equation is essentially similar to previously published relations. At 20 °C, the poikilotherm relation is slightly higher, and the unicell relation considerably lower, than Hemmingsen's widely cited relations. Enough data were available to provide a statistical description of active reptiles and fish: [Formula: see text]; this relationship may be used to approximate the metabolic rate of actively foraging fish and reptiles. Equations for the standard metabolic rate can serve as components in the calculation of minimal metabolic rates of homeotherms and higher poikilotherms in nature; such values could then be increased by estimates of the additional demands associated with movement, feeding, growth, etc. For unicells and lower vertebrates, standard rates also serve as estimates of free-living rates.

The effect of temperature on standard metabolic rate of Brown Anoles

2012 ◽  
Vol 33 (2) ◽  
pp. 297-302 ◽  
Author(s):  
John E. Steffen ◽  
Arthur G. Appel
Keyword(s):  
Oxygen Consumption ◽  
Metabolic Rate ◽  
Life History Evolution ◽  
Standard Metabolic Rate ◽  
Geographic Range ◽  
Effect Of Temperature ◽  
Metabolic Rates ◽  
Temperature Dependent ◽  
Fundamental Interest ◽  
Male And Female

Understanding the influences of sex and ambient temperature on metabolic rates of reptiles is of fundamental interest to biologists because of the role that temperature-dependent metabolic rates play in shaping behaviour, life history evolution and geographic range. We investigated the effects of sex, body mass and temperature on standard metabolic rate, respiratory quotient (RQ), and Q10 in male and female Brown Anoles, Norops sagrei. When mass-adjusted, oxygen consumption increased linearly with temperature, and there was no effect of sex. RQ did not differ by sex or temperature. Q10 was within the range published for other lizards.

Effect of triiodothyronine on body temperature at rest and during exercise in dogs

1983 ◽  
Vol 54 (4) ◽  
pp. 1115-1119 ◽  
Author(s):  
J. M. Stager
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Thyroid Hormones ◽  
Metabolic Rate ◽  
Rectal Temperature ◽  
Metabolic Rates ◽  
Rest And Exercise

To determine the effect of the thyroid hormones on body temperature at rest and during exercise, five mongrel dogs were trained to run on a treadmill and then treated with exogenous triiodothyronine (T3) (1 mg/kg) to elevate circulating T3 levels or propylthiouracil (PTU) (200 mg/day for 14 days) to lower endogenous T3 levels. When compared with levels in euthyroid controls at rest and during exercise, rectal temperature (Tre) was increased (P less than or equal to 0.01 and P less than or equal to 0.02, rest and exercise, respectively) in T3-treated dogs and decreased (P less than 0.05 and P less than 0.01) in the PTU-treated dogs. Although the rise in Tre from rest to exercise in the PTU trial was slightly less than that of the control runs (1.23 vs 1.44 degrees C, respectively; P = 0.05), it was similar to the rise in Tre observed in the T3 experiments (1.37 degrees C). Because T3 treatment resulted in an elevation in exercise oxygen consumption (VO2), untreated dogs were run at elevated work loads such that their VO2 matched that recorded when pretreated with T3. Exercise Tre in these experiments was lower (P less than 0.02) than after T3 treatment, even though the exercise metabolic rates were equivalent. It was concluded that 1) although T3 alters body temperature, the magnitude of the rise in Tre during exercise is not dependent on T3 concentration and 2) the effects of T3 on body temperature at rest and during exercise are mediated through mechanisms other than alterations in metabolic rate.

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.

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.

Metabolic phenotype is not associated with vulnerability to angling in bluegill sunfish (Lepomis macrochirus)

2018 ◽  
Vol 96 (11) ◽  
pp. 1264-1271 ◽  
Author(s):  
Michael J. Louison ◽  
J.A. Stein ◽  
C.D. Suski
Keyword(s):  
Oxygen Consumption ◽  
Metabolic Rate ◽  
Recovery Time ◽  
Lepomis Macrochirus ◽  
Metabolic Phenotype ◽  
Intermittent Flow ◽  
Bluegill Sunfish ◽  
Metabolic Rates ◽  
Prior Work ◽  
Context Specific

Prior work has described a link between an individual’s metabolic rate and a willingness to take risks. One context in which high metabolic rates and risk-prone behaviors may prove to be maladaptive is in fish that strike fishing lures only to be captured by anglers. It has been shown that metabolic phenotype may be altered by angling; however, little work has assessed metabolic rate in fish and its relationship to angling vulnerability in a realistic angling trial. To address this, we subjected a set of bluegill sunfish (Lepomis macrochirus Rafinesque, 1819) to a series of angling sessions. Following this, a subset of 23 fish that had been captured at least once and 25 fish that had not been captured were assessed for metabolic phenotype (standard and maximum metabolic rates, postexercise oxygen consumption, and recovery time) via intermittent flow respirometry. Contrary to predictions, captured and uncaptured fish did not differ in any measurement of metabolic rate. These results suggest that metabolic phenotype is not a determinant of angling vulnerability within the studied context. It is possible, therefore, that previously described alterations in metabolic phenotype owing to angling pressure may be context-specific and may not apply to all species and angling contexts.

Interaction Between Thyroxine and Dibenzyline on Metabolic Rate

1957 ◽  
Vol 191 (3) ◽  
pp. 573-576 ◽  
Author(s):  
Neena B. Schwartz ◽  
Gerald E. Hammond ◽  
Gerald A. Gronert
Keyword(s):  
Oxygen Consumption ◽  
Synergistic Effect ◽  
Metabolic Rate ◽  
Pressor Effect ◽  
Metabolic Rates ◽  
Thyroid Status ◽  
Experimental Animals ◽  
Rate Of Oxygen Consumption

Doses of Dibenzyline adequate to block the pressor effect of epinephrine were administered to rats with various degrees of chronic hypo- or hyperthyroidism. Rate of oxygen consumption was measured under barbiturate anesthesia. Dibenzyline decreased or did not change hypothyroid metabolic rates, but increased metabolic rates in hyperthyroid rats. The data indicated that Dibenzyline exerts a synergistic effect with thyroxine on metabolism resembling the previously reported synergism between thyroxine and epinephrine. Apparently discrepant findings presented in the literature regarding the interaction of thyroxine and Dibenzyline probably result from differences in the thyroid status of the experimental animals.

SOME PHYSIOLOGICAL AND NUTRITIONAL ASPECTS OF THE DWARF CHICKEN

1971 ◽  
Vol 51 (1) ◽  
pp. 209-216 ◽  
Author(s):  
G. RAJARATNAM ◽  
J. D. SUMMERS ◽  
A. S. WOOD ◽  
E. T. MORAN Jr.
Keyword(s):  
Body Weight ◽  
Oxygen Consumption ◽  
Weight Gain ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Body Weight Gain ◽  
Carcass Composition ◽  
Lower Body ◽  
Brand Name ◽  
Dwarf Chicken

A study was undertaken to investigate the feasibility of hypothyroidism as an explanation for the smaller body size and lower metabolic activity of the recessive sex-linked dwarf chicken. A significant increase in body weight gain and feed intake for dwarf chicks with little change in these parameters for normal chicks receiving a diet supplemented with Protamone (brand name for iodinated casein) suggests a hypothyroidic state for the dwarfs. Similarly, a significantly lower body temperature, oxygen consumption and basal metabolic rate with a higher percentage of carcass fat in dwarf chicks as compared with normal ones supports the above hypothesis. Protamone supplementation of the diet increased body temperature and metabolic rate, and altered the carcass composition of the dwarfs to values closer to that of normal chicks, again suggesting a low thyroxine output for the dwarfs.

The metabolic rate and thermal conductance of the eastern barred bandicoot (Perameles gunnii) at different ambient temperatures

2003 ◽  
Vol 51 (6) ◽  
pp. 603 ◽  
Author(s):  
M. P. Ikonomopoulou ◽  
R. W. Rose
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Thermal Conductance ◽  
The Body ◽  
High Metabolic Rate ◽  
Ambient Temperatures ◽  
Reduced Body ◽  
Thermoneutral Zone ◽  
Reproductive Females

We investigated the metabolic rate, thermoneutral zone and thermal conductance of the eastern barred bandicoot in Tasmania. Five adult eastern barred bandicoots (two males, three non-reproductive females) were tested at temperatures of 3, 10, 15, 20, 25, 30, 35 and 40°C. The thermoneutral zone was calculated from oxygen consumption and body temperature, measured during the daytime: their normal resting phase. It was found that the thermoneutral zone lies between 25°C and 30°C, with a minimum metabolic rate of 0.51 mL g–1 h–1 and body temperature of 35.8°C. At cooler ambient temperatures (3–20°C) the body temperature decreased to approximately 34.0°C while the metabolic rate increased from 0.7 to 1.3 mL g–1�h–1. At high temperatures (35°C and 40°C) both body temperature (36.9–38.7°C) and metabolic rate (1.0–1.5 mL g–1 h–1) rose. Thermal conductance was low below an ambient temperature of 30°C but increased significantly at higher temperatures. The low thermal conductance (due, in part, to good insulation, a reduced body temperature at lower ambient temperatures, combined with a relatively high metabolic rate) suggests that this species is well adapted to cooler environments but it could not thermoregulate easily at temperatures above 30°C.

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