Physiology of thermoregulation in the pika, Ochotona princeps

1973 ◽  
Vol 51 (1) ◽  
pp. 11-16 ◽  
Author(s):  
Robert A. MacArthur ◽  
Lawrence C. H. Wang

The mean body temperature of pika measured by radiotelemetry under field and laboratory conditions was 40.1 °C (range = 37.9–42.7) over an ambient temperature range of −9.3 to 24 °C. The maximum daily fluctuation in any one individual was less than 2.6 °C and no seasonal difference in the level of body temperature maintained was observed. Hyperthermia and death occurred after a 2-h exposure to ambient temperatures higher than 28 °C, inclusive.The basal metabolic rate was 1.53 cc O2/g h and the thermal conductance was between 0.096 and 0.050 cc O2/gh °C, 143% and 101–53%, respectively, of their predicted weight-specific values. The relatively high body temperature of pika is attributed to its high basal metabolic rate and good insulation. The low thermal conductance, which indicates a reduction of energy consumption at ambient temperatures below the lower critical temperature (21 °C), favors the overwinter survival of this species when only limited food storage is available.

1999 ◽  
Vol 47 (2) ◽  
pp. 143 ◽  
Author(s):  
Claus Bech ◽  
Stewart C. Nicol

Oxygen consumption (VO2) and body temperature (Tb) were measured during daytime (corresponding to the normal resting phase) in the tawny frogmouth (Podargus strigoides, mean body mass of 341 g) at ambient temperatures (Ta) between -1ºC and 30ºC. Mean body temperature (over this range of Ta) was 37.8ºC and there was only a small (0.4ºC), and insignificant, day-night variation in Tb. Mean VO2 within thermoneutrality (25-30ºC) was 0.59 mL O2 g-1 h-1 , corresponding to a basal metabolic rate (BMR) of 3.32 W kg-1 . This value is only 61% of the predicted value for a non-passeriform bird. The minimal thermal conductance attained at Ta below thermoneutrality was 0.156 W kg-1 ºC-1, a value which is very close to the allometrically predicted value. The relatively low VO2 was paralleled by a low total ventilatory volume. This, in turn, was mainly the result of a low respiratory frequency (10.2 breaths min-1, only 52% of that expected for a similar-sized bird) whereas tidal volume (6.6 mL [BTPS]) was 107% of the expected value. Thus, our results suggest that the changing ventilatory needs during the evolution of the low VO2 in the tawny frogmouth have been met primarily by changes in respiratory frequency.


2006 ◽  
Vol 54 (1) ◽  
pp. 9 ◽  
Author(s):  
Alexander N. Larcombe ◽  
Philip C. Withers ◽  
Stewart C. Nicol

Thermoregulatory, metabolic and ventilatory parameters measured for the Tasmanian eastern barred bandicoot (Perameles gunnii) in thermoneutrality (ambient temperature = 30°C) were: body temperature 35.1°C, basal metabolic rate 0.55 mL O2 g–1 h–1, wet thermal conductance 2.2 mL O2 g–1 h–1 °C–1, dry thermal conductance 1.4 J g–1 h–1 °C–1, ventilatory frequency 24.8 breaths min–1, tidal volume 9.9 mL, minute volume of 246 mL min–1, and oxygen extraction efficiency 22.2%. These physiological characteristics are consistent with a cool/wet distribution, e.g. high basal metabolic rate (3.33 mL O2 g–0.75 h–1) for thermogenesis, low thermal conductance (0.92 J g–1 h–1 °C–1 at 10°C) for heat retention and intolerance of high ambient temperatures (≥35°C) with panting, hyperthermia and high total evaporative water loss (16.9 mg H2O g–1 h–1).


1973 ◽  
Vol 51 (8) ◽  
pp. 841-846 ◽  
Author(s):  
Lawrence C. H. Wang ◽  
Douglas L. Jones ◽  
Robert A. MacArthur ◽  
William A. Fuller

Unlike other lagomorphs or any other mammals living in a cold environment, the basal metabolic rate of the arctic hare, Lepus arcticus monstrabilis (0.36 cm3 O2/g per hour) was only 62–83% of the values predicted from its body weight. The minimum thermal conductance (0.010 cm3 O2/g per hour per degree centigrade) was also reduced to only 51–59% of its weight-specific value (0.019–0.017 cm3 O2/g per hour per degree centigrade). The normal body temperature (38.9C), however, was comparable to that of other lagomorphs. The daily energy consumption between ambient temperatures of −24 and 12.5C was between 262 and 133 kcal, which is 6–43% above the minimum resting values at corresponding ambient temperatures.It is concluded that the reduction of surface area to volume ratio and the effectiveness of its insulation are sufficient compensations so that the arctic hare can maintain a normal body temperature with a depressed basal metabolic rate. Such a reduction of metabolism is energetically adaptive for a species living exclusively in a cold and relatively barren habitat.


2003 ◽  
Vol 51 (6) ◽  
pp. 603 ◽  
Author(s):  
M. P. Ikonomopoulou ◽  
R. W. Rose

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.


1992 ◽  
Vol 40 (5) ◽  
pp. 523 ◽  
Author(s):  
PC Withers

The Barrow I. golden bandicoot (Isoodon auratus) is a small arid-adapted marsupial. It has a low and labile body temperature, a low basal metabolic rate, a low thermal conductance, and a low rate of evaporative water loss. Its metabolic, thermal and hygric physiology resembles that of another arid-adapted bandicoot, the bilby, and differs from temperate and tropical bandicoots.


1999 ◽  
Vol 47 (2) ◽  
pp. 169 ◽  
Author(s):  
Elke Schleucher

Ptilinopus superbus (body mass 120.4 5.2 g) is a highly specialised, migratory avian frugivore that is widespread in the rainforests of the Indo-Pacific Region and north-eastern Australia. The effect of the specialised diet on metabolic rate (MR) and body temperature (Tb) were investigated at ambient temperatures (Ta) of 13-30ºC in activity (α) and rest (ρ) phases. At thermoneutrality (Ta = 26ºC), the basal metabolic rate (BMR) was 23.2 4.49 J g-1 h-1 , which corresponds closely to the predicted value (22.6 J g-1 h-1). Wet thermal conductance (Cwet) was 2.39 0.45 J g-1 h-1 ºC-1 in α and 1.75 0.13 J g-1 h-1 ºC-1 in ρ for Ta between 13 and 21ºC. These conductances are higher than expected (α: 1.87 J g-1 h-1 ºC-1; ρ: 1.16 J g-1 h-1 ºC-1) for a non-passerine bird of this body mass (M), indicating poor insulation of this tropical species. Tb was 39.6 0.76ºC in α and 38.1 0.55ºC in ρ in the observed Ta range, corresponding closely to expected values (40.9 1.35 in α and 38.6 0.66 in ρ). This study shows no evidence of an influence of the fruit diet on the metabolic physiology of superb fruit doves. Analysis of BMR data for all pigeon species sampled so far provides no evidence that a low basal metabolic rate is a general characteristic of the Columbidae.


2006 ◽  
Vol 54 (1) ◽  
pp. 15 ◽  
Author(s):  
Alexander N. Larcombe ◽  
Philip C. Withers

The metabolic, thermoregulatory and ventilatory physiology of western barred bandicoots (Perameles bougainville bougainville), measured in the laboratory during summer and winter at ambient temperatures of 10 and 30°C, is relatively unusual for a peramelid marsupial. It has a low thermoneutral body temperature (33.7 ± 0.2°C), a very high basal metabolic rate (0.68 ± 0.03 mL O2 g–1 h–1 at ambient temperature = 30°C), low respiratory exchange ratios (often less than 0.7) and a high thermal conductance, reflecting its high oxygen consumption rate and low body temperature. Ventilatory frequency and tidal volume were variable between seasons, although minute volume and oxygen extraction efficiency were not. Minute volume of the western barred bandicoot was higher than expected, reflecting its high metabolic rate. Time of year (i.e. season) had an effect on some aspects of metabolic, thermoregulatory and ventilatory physiology (carbon dioxide production, respiratory exchange ratio, total evaporative water loss), but this effect was not as substantial nor as general as the effect of ambient temperature.


Nature ◽  
2019 ◽  
Vol 572 (7771) ◽  
pp. 651-654 ◽  
Author(s):  
Jorge Avaria-Llautureo ◽  
Cristián E. Hernández ◽  
Enrique Rodríguez-Serrano ◽  
Chris Venditti

The Condor ◽  
2006 ◽  
Vol 108 (4) ◽  
pp. 966-970
Author(s):  
Mark Williamson ◽  
Joseph B. Williams ◽  
Erica Nol

Abstract Abstract The Semipalmated Plover (Charadriussemipalmatus), anarctic-nesting migratory shorebird, regularlyencounters low temperatures during the breedingseason. We measured the basal metabolism of adultsduring incubation at Churchill, Manitoba, Canada todetermine basal metabolic rate (BMR),lower critical temperature(Tlc), total evaporative waterloss (TEWL), and dry thermal conductance(Cm). BMR and Tlcwere 47.4 kJ day−1and 23.3°C, respectively, TEWL was2.5 mL H2O−d,and Cm was1.13 mW g−1 °C−1.Measured BMR and Tlc were consistentwith high values found for other shorebird speciesbreeding in the Arctic, while Cm was18% higher than predicted from allometricequations. These metabolic data suggest thatSemipalmated Plovers are adapted to balance therequirements of incubation against energetic andthermoregulatory demands in the Arctic, especiallyin harsh early breeding season conditions.


1994 ◽  
Vol 266 (4) ◽  
pp. R1319-R1326 ◽  
Author(s):  
E. Dumonteil ◽  
H. Barre ◽  
J. L. Rouanet ◽  
M. Diarra ◽  
J. Bouvier

Penguins are able to maintain a high and constant body temperature despite a thermally constraining environment. Evidence for progressive adaptation to cold and marine life was sought by comparing body and peripheral skin temperatures, metabolic rate, and thermal insulation in juvenile and adult Gentoo penguins exposed to various ambient temperatures in air (from -30 to +30 degrees C) and water (3-35 degrees C). Juvenile penguins in air showed metabolic and insulative capacities comparable with those displayed by adults. Both had a lower critical temperature (LCT) close to 0 degree C. In both adults and juveniles, the intercept of the metabolic curve with the abscissa at zero metabolic rate was far below body temperature. This was accompanied by a decrease in thermal insulation below LCT, allowing the preservation of a threshold temperature in the shell. However, this shell temperature maintenance was progressively abandoned in immersed penguins as adaptation to marine life developed, probably because of its prohibitive energy cost in water. Thus adaptation to cold air and to cold water does not rely on the same kind of reactions. Both of these strategies fail to follow the classical sequence linking metabolic and insulative reactions in the cold.


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