Effect of environmental temperature on body temperature and metabolic heat production in a heterothermic rodent,Spermophilus tereticaudus

2002 ◽  
Vol 205 (14) ◽  
pp. 2099-2105 ◽  
Author(s):  
K. Mark Wooden ◽  
Glenn E. Walsberg

SUMMARYThis study quantifies the thermoregulatory ability and energetics of a mammal, the round-tailed ground squirrel Spermophilus tereticaudus,that can relax thermoregulatory limits without becoming inactive. We measured body temperature and metabolic rate in animals exposed for short periods (1 h)to air temperatures ranging from 10 to 45 °C and for long periods (8 h) to air temperatures ranging from 10 to 30 °C. Within 45 min of exposure to air temperatures ranging from 10 to 45 °C, the mean body temperatures of alert and responsive animals ranged from 32.1 °C(Tair=10 °C) to 40.4 °C(Tair=45 °C). This thermolability provided significant energetic savings below the thermoneutral zone, ranging from 0.63 W (18 %) at 10 °C to 0.43 W (43 %) at 30 °C. When exposed for 8 h to air temperatures between 10 and 30 °C, animals varied their body temperature significantly over time. At all air temperatures, the lowest body temperature(maintained for at least 1 h) was 31.2 °C. The highest body temperatures(maintained for at least 1 h) were 33.6 °C at 10 °C, 35.3 °C at 20°C and 36.3 °C at 30 °C. The energetic savings realized by maintaining the minimum rather than the maximum body temperature was 0.80 W(25 %) at 10 °C, 0.71 W (33 %) at 20 °C and 0.40 W (47 %) at 30°C. This study demonstrates in several ways the ability of this species to adjust energy expenditure through heterothermy.

1951 ◽  
Vol 29 (3) ◽  
pp. 224-233 ◽  
Author(s):  
J. S. Hart

A method is described for determining average body temperature of mice by placing them immediately after killing in a Dewar flask containing water and recording the temperature rise. Evidence is presented to show that postmortem heat production does not contribute appreciably to the results. Average body temperatures are usually about 2 °C. lower than colonic temperatures except during lethal chilling when average temperatures are frequently higher than colonic. The rise in average body temperature produced by activity increases with environmental temperature. Body temperatures may be lower during activity than during rest at cold air temperatures.


1990 ◽  
Vol 68 (8) ◽  
pp. 1659-1663 ◽  
Author(s):  
Gregory P. Brown ◽  
Ronald J. Brooks ◽  
James A. Layfield

We wished to determine whether free-ranging snapping turtles (Chelydra serpentina) would use aquatic and atmospheric basking to maintain body temperature at the mean temperature (28–30 °C) selected by snapping turtles placed in a controlled aquatic thermal gradient. Body temperatures from eight adult snapping turtles in three different lakes in Algonquin Provincial Park were monitored by radiotelemetry during July and August 1987. Mean body temperature of all eight turtles over the study period was 22.7 °C, and mean temperature of every individual was well below the reported mean selected temperature for this species. The turtles did not maintain body temperatures near the available maximum environmental temperature. The mean body temperatures of the turtles were not significantly different among the three study lakes although these lakes had different physical characteristics. Similarly, there were no significant differences, among individual turtles, between air temperatures or operative environmental temperatures recorded concurrently with their body temperatures Nevertheless, mean body temperatures differed significantly among individuals; foraging tactics, metabolic rates, and home range structure may account for these differences.


1963 ◽  
Vol 18 (5) ◽  
pp. 1016-1018 ◽  
Author(s):  
J. A. Panuska ◽  
Vojin Popovic

Inexperienced shaved adult white rats cooled to a colonic temperature of 18.5 C and then rewarmed to 26.0 C, were placed at an ambient temperature of 2.0 C with the possibility of using a lever-activated heat reinforcement apparatus. Their body temperatures leveled at 29 C; and during the next 40–80 min the rats either learned to press the lever systematically for external heat and thereby rewarmed themselves to euthermia, or they drifted into deeper hypothermia leading to death. Activity records and visual observations indicate that after an average of 48 min and at a body temperature of 29.6 C (28.5–30.2 C), out of a group of 14 rats 12 learned this technique necessary for their survival. All 12 rats reached euthermia and continued to use the lever as long as they remained in the experimental situation. It is concluded that learning is possible even at a low body temperature of 29.6 C. performance; heat reinforcement; temperature regulation; body temperature; environmental temperature; operant behavior; survival studies; motivation; physiology of learning; cold physiology Submitted on March 7, 1963


1984 ◽  
Vol 5 (1) ◽  
pp. 37-41 ◽  
Author(s):  
David Stubbs ◽  
Adrian Hailey ◽  
Elizabeth Pulford

AbstractThe mean body temperature of T. hermanni in woodland in France was 28.5 °C (August 1981). Body temperatures were elevated above air temperature and indirect evidence for basking and selection of an optimal microenvironment is discussed.


1960 ◽  
Vol 55 (3) ◽  
pp. 295-302 ◽  
Author(s):  
R. B. Symington

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.


1960 ◽  
Vol 11 (5) ◽  
pp. 871 ◽  
Author(s):  
DF Dowling

An experiment was performed to test the effect of solar radiation on the body temperatures of cattle, both clipped and with hair coat, in a clear transparent plastic covering as compared with cattle in a white reflective plastic covering. The mean body temperature of the animals in white plastic coats was 0.15°F lower than that of animals in clear plastic coats. This difference was highly significant statistically (P< 0.001). Animals in both clear and white coats had higher body temperatures than controls without plastic coats. The difference was highly significant, and was about 1.5°F in the clipped animals.


1985 ◽  
Vol 59 (2) ◽  
pp. 413-419 ◽  
Author(s):  
A. R. Gwosdow ◽  
E. L. Besch

After acclimating individually housed male rats to temperatures of either 24.5 +/- 0.1 or 29.2 +/- 0.1 degrees C for 14 days, randomly paired animals from each group were acutely exposed (3 h) in series to experimental temperatures between 18.0 and 34.5 degrees C in a controlled environment room. Relative humidity of 50 +/- 0.3% and a 12-h light-dark photoperiod (light from 0900 to 2100 h) were maintained. Metabolic rate (MR) and evaporative water loss (EWL) were-measured using an open-flow system; thermistors were used to measure the rectal (Tre) and tail skin (Tts) temperatures. MR was relatively constant over a temperature range of 22.2 to 27.0 degrees C for rats acclimated to 24.5 degrees C and 20.0 to 29.2 degrees C for rats acclimated to 29.2 degrees C. Above and below these ranges, MR for both groups was significantly (P less than 0.05) elevated. At their respective acclimation temperatures, the absolute Tre and Tts of 29.2 degrees C rats were maintained at an elevated level compared with 24.5 degrees C rats. Although EWL for both groups was relatively constant between 18.0 and 27.0 degrees C, 24.5 degrees C rats displayed higher EWL changes at most environmental temperatures above 27.0 degrees C. At 34.5 degrees C, 29.2 degrees C rats dissipated 26% more metabolic heat by evaporation compared with 24.5 degrees C rats. These data suggest that acclimation temperatures of rats affected the thermoneutral zone and alter the set-point temperature around which thermal responses are regulated.


PEDIATRICS ◽  
1993 ◽  
Vol 92 (2) ◽  
pp. 238-240
Author(s):  
Tina L. Cheng ◽  
J. Colin Partridge

Objective. The effect of bundling and ambient heat on newborn body temperature has not been systematically studied. It was hypothesized that bundling and warm environments can elevate the newborn's temperatures to the range that would prompt clinical concern of neonatal sepsis. Methods. Twenty well, term newborns more than 1 day old were assigned to the control group (one blanket; 24.0°C room) or the experimental group (five blankets and hat; 26.6°C room). Continuous rectal probe temperatures were monitored over a 2½hour period. Results. There were 8 control and 12 experimental newborns. The mean change in rectal temperature after 2½ hours was -0.04°C (SD ± 0.23) in control newborns and + 0.56°C (SD ± 0.12) in the treatment group (P &lt; .0001, t test). Temperatures in the treatment group rose, after an initial half-hour lag, at a linear rate of 0.27°C per hour without a plateau. Two newborns reached 38.0°C, a rectal temperature that may raise concern of infection. Conclusions. Bundling and warm environments can elevate newborn body temperature to the "febrile" range in this age group. Physicians treating neonates with elevated temperature should ask about bundling and environmental conditions to differentiate endogenous from exogenous "fevers."


2020 ◽  
Vol 42 (1) ◽  
pp. 81-91
Author(s):  
Jalal Mouadi ◽  
El Hassan El Mouden ◽  
Abdellah Bouazza ◽  
Mohamed Aourir

Abstract The Atlas day gecko, Quedenfeldtia moerens, a Moroccan endemic lizard, is strictly diurnal and widely distributed across the dry Atlas Mountains. We quantified thermoregulation in adult males and adult females during their active season in the L’kest Mountain at 1300 m a.s.l., Anti-Atlas region of Morocco. The operative temperatures and air temperatures were sampled using data-loggers in the field from 2016 to 2018. Body temperatures of active lizards and substrate temperatures in the field were simultaneously measured. Finally, we measured preferred body temperatures (Tset) in a laboratory thermal gradient for 24 adult geckos. Mean Tset was 33.3 ± 0.3°C, with the mean 25% and 75% quartiles being 32.3 ± 0.3°C and 34.6 ± 0.3°C, respectively. Active lizards rarely reached their Tset range from March to June, but spent most of the day within Tset in July and August. Our study suggests that Q. moerens have higher Tset than its congeneric Q. trachyblepharus living at high altitude. Likewise, thermoregulatory effectiveness of Q. moerens showed an increase from spring to summer while it was the opposite for Q. trachyblepharus.


2019 ◽  
Vol 18 (2) ◽  
pp. 225-240
Author(s):  
Raul Fernandes Dantas Sales ◽  
Eliza Maria Xavier Freire

Behavioral adaptations in Ameivula ocellifera (Squamata: Teiidae) in response to thermal environmental changes. Lizards rely on external sources to regulate body temperature, but in many species, it is not known whether lizards are able to change their thermoregulatory behaviors in response to variations in thermal environments. The seasonal thermal ecology of three populations of the Brazilian whiptail lizard, Ameivula ocellifera, in northeastern Brazil (two Caatinga sites and one in the Atlantic Forest) was investigated. The relationships between body temperature and microhabitat temperatures (substrate and air), and between body temperature and thermoregulatory behavior (i.e., time of exposure to sunlight classes and time spent basking) were explored. The average body temperatures of the lizards were 38–39°C; these neither varied seasonally nor among populations. Substrate and air temperatures are lower at the natural Caatinga site, and lizards in there spent less time in the shade and more time exposed to the sun. Microhabitat temperatures vary seasonally in natural Caatinga; they are lower in the rainy season, when lizards spent more time exposed to sun and less time in fltered sun. Lizard body temperatures exceeded microhabitat temperatures in the rainy season in all three populations; however, they did not exceed substrate temperature in the dry season. In each of the populations, lizards with low body temperatures during cloudy conditions spent more time basking. Thus, A. ocellifera adjusts its body temperature behaviorally to compensate for seasonal changes in environmental temperatures, as well as geographic thermal variation throughout its range.


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