Energy metabolism and thermoregulation of beaver (Castor canadensis)

1989 ◽  
Vol 67 (3) ◽  
pp. 651-657 ◽  
Author(s):  
Robert A. MacArthur
Keyword(s):  
Critical Temperature ◽  
Castor Canadensis ◽  
Resting Metabolic Rate ◽  
Whole Body ◽  
Metabolic Rates ◽  
Body Temperatures ◽  
Thermoneutral Zone ◽  
Air Temperatures ◽  
Lower Critical Temperature ◽  
Predicted Values

Metabolic rates and body temperatures (Tb) of adult and immature beavers were recorded at air temperatures from −20 to 28 °C. The thermoneutral zone of beavers > 1 year of age extended from 0–2 °C to at least 28 °C. Lower critical temperature, whole-body conductance, and resting metabolic rate were similar for yearlings and beavers ≥ 2 years old, and conformed closely to weight-predicted values for terrestrial eutherians. The estimated lower critical temperature of a growing beaver kit declined from 24–25 °C at 2–3 weeks of age when the animal weighed 0.59–0.62 kg to 0–2 °C at 11–13 weeks when the kit weighed 2.92–3.50 kg. Rectal Tb of the kit was generally lower and less stable than abdominal Tb recorded telemetrically from older animals. In beavers > 1 year old, abdominal Tb was independent of air temprature (−20 to 28 °C), with no evidence of hypothermia or metabolic depression at subfreezing temperatures. Neither the level nor the daily rhythm of Tb was substantially altered by 24–48 h fasting in this species.

Aquatic thermoregulation of captive and free-ranging beavers (Castor canadensis)

1990 ◽  
Vol 68 (11) ◽  
pp. 2409-2416 ◽  
Author(s):  
Robert A. MacArthur ◽  
Alvin P. Dyck
Keyword(s):  
Metabolic Rate ◽  
Cold Water ◽  
Castor Canadensis ◽  
Resting Metabolic Rate ◽  
Whole Body ◽  
Passive Cooling ◽  
Metabolic Rates ◽  
The Mean ◽  
Free Ranging ◽  
Skin Temperatures

Abdominal cooling occurred in 91% of all aquatic excursions documented in free-ranging beavers during fall and winter. Kits aged 4–7 months cooled faster and spent less time foraging in 1–12 °C water than did animals > 1 year old. All beavers tested in the laboratory displayed abdominal cooling in 2–20 °C water, with maximal cooling rates recorded in a 5- to 7-week-old kit. Immersion in cold water induced strong peripheral cooling, though skin temperatures beneath the pelage remained within 4–5 °C of abdominal measurements. The resting metabolic rate of beavers > 1 year old was independent of water temperature between 19 and 31 °C, but increased proportionately at lower temperatures. Whole-body conductance of resting animals was on average 1.6–3.0 times higher in water than in air. Maximum testing metabolic rates in water varied from 1.8 to 2.4 times the mean resting thermoneutral rate in air. Our results suggest that beavers mitigate the thermogenic effort required in water by adopting a thermoregulatory strategy which combines avoidance of prolonged immersion with a tolerance to passive cooling.

Metabolism and temperature regulation in young harbor seals Phoca vitulina richardi

1975 ◽  
Vol 229 (2) ◽  
pp. 506-511 ◽  
Author(s):  
K Miller ◽  
L Irving
Keyword(s):  
Critical Temperature ◽  
Low Temperatures ◽  
Resting Metabolic Rate ◽  
Thermal Conductance ◽  
Phoca Vitulina ◽  
Harbor Seals ◽  
Ambient Conditions ◽  
Air Temperatures ◽  
Lower Critical Temperature ◽  
Tissue Insulation

Metabolism and the ability to regulate core and peripheral temperatures under a variety of ambient conditions were studied in five unrestrained pups (less than 5 wk old) and four 3- to 5-mo-old harbor seals. Pups born with nonlanugo (adultlike) hair and little fat were able to swim in 5 degrees C water for several hours without becoming hypothermic. They were also found to tolerate 5 degrees C air temperature with the fur wet and exposed to a 35-knot wind. Basal metabolism in pups averaged 0.8 ml O2 g-1 h-1, which is 2.6 times the predicted value for an adult mammal of the same weight. Lower critical temperature in air was about 3 degrees C. Oxygen uptake in 3- to 5-mo-old seals under basal conditions was 0.5 ml g-1 h-1. Minimal thermal conductance values were .02 and .015 ml O2 g-1 h-1 degrees C-1 in pumps and 3- to 5-month-old seals, respectively. Appendages, and to a lesser extent the skin on the torso, cooled appreciably at lower air temperatures, and the flippers were kept just above freezing in subzero air. Tissue insulation provided by low peripheral temperatures and a high resting metabolic rate enable newborn and developing harbor seals to tolerate the low temperatures encountered in their natural environment.

Thermoregulation in the only nocturnal simian: the night monkey Aotus trivirgatus

1981 ◽  
Vol 240 (3) ◽  
pp. R156-R165 ◽  
Author(s):  
Y. Le Maho ◽  
M. Goffart ◽  
A. Rochas ◽  
H. Felbabel ◽  
J. Chatonnet
Keyword(s):  
Critical Temperature ◽  
Metabolic Rate ◽  
Response Pattern ◽  
Thermal Environment ◽  
Resting Metabolic Rate ◽  
Thermal Conductance ◽  
Open Circuit ◽  
The Body ◽  
Thermoneutral Zone ◽  
Lower Critical Temperature

The night monkey, a tropical monkey, is the only nocturnal simian; its thermoregulation was studied for comparison with other nocturnal or diurnal primates and other tropical mammals. Resting metabolic rate was 2.6 W (closed-circuit method) and 2.8 W (open-circuit method), 24 and 18% below the value predicted from body mass. The thermoneutral zone was very narrow; the lower critical temperature (LCT) was 28 degrees C and the upper critical temperature (UCT) was 30 degrees C. The body temperature (Tb) was at its minimum (38 degrees C) at an ambient temperature (Ta) of 25 degrees C, thus below the LCT. At low Ta, the increase in metabolic rate (MR) was smaller than predicted by the Scholander model, since MR intersected to a Ta 13 degrees C above Tb when extrapolated to MR = 0; this was attributed to a decrease of body surface area by behavior. The thermal conductance at the LCT was low: 2.3 W . m-2 . degrees C-1. Above the UCT, panting was the major avenue of heat loss. The response pattern of nocturnal habits, low resting metabolic rate, low thermal conductance, and panting in the night monkey, unique among simians, is found in many other mammals of tropical and hot desert habitats; it may be considered as an alternative adaptation to the thermal environment.

scholarly journals Field metabolic rates of giant pandas reveal energetic adaptations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wenlei Bi ◽  
Rong Hou ◽  
Jacob R. Owens ◽  
James R. Spotila ◽  
Marc Valitutto ◽  
...  
Keyword(s):  
Critical Temperature ◽  
Metabolic Rate ◽  
Grizzly Bears ◽  
Metabolic Rates ◽  
Giant Pandas ◽  
Fat Stores ◽  
Doubly Labeled Water Method ◽  
Field Metabolic Rates ◽  
Predicted Values

AbstractKnowledge of energy expenditure informs conservation managers for long term plans for endangered species health and habitat suitability. We measured field metabolic rate (FMR) of free-roaming giant pandas in large enclosures in a nature reserve using the doubly labeled water method. Giant pandas in zoo like enclosures had a similar FMR (14,182 kJ/day) to giant pandas in larger field enclosures (13,280 kJ/day). In winter, giant pandas raised their metabolic rates when living at − 2.4 °C (36,108 kJ/day) indicating that they were below their thermal neutral zone. The lower critical temperature for thermoregulation was about 8.0 °C and the upper critical temperature was about 28 °C. Giant panda FMRs were somewhat lower than active metabolic rates of sloth bears, lower than FMRs of grizzly bears and polar bears and 69 and 81% of predicted values based on a regression of FMR versus body mass of mammals. That is probably due to their lower levels of activity since other bears actively forage for food over a larger home range and pandas often sit in a patch of bamboo and eat bamboo for hours at a time. The low metabolic rates of giant pandas in summer, their inability to acquire fat stores to hibernate in winter, and their ability to raise their metabolic rate to thermoregulate in winter are energetic adaptations related to eating a diet composed almost exclusively of bamboo. Differences in FMR of giant pandas between our study and previous studies (one similar and one lower) appear to be due to differences in activity of the giant pandas in those studies.

Developmental and seasonal changes in resting metabolic rates of captive female grey seals

1997 ◽  
Vol 75 (11) ◽  
pp. 1781-1789 ◽  
Author(s):  
Patrice Boily ◽  
David M. Lavigne
Keyword(s):  
Metabolic Rate ◽  
Body Mass ◽  
Adult Female ◽  
Significant Relationship ◽  
Seasonal Changes ◽  
Resting Metabolic Rate ◽  
Halichoerus Grypus ◽  
Metabolic Rates ◽  
In Captivity ◽  
Predicted Values

Resting metabolic rate (RMR) data obtained from five juvenile and three adult female grey seals (Halichoerus grypus) in captivity over a period of 3.5 years were examined for developmental and seasonal changes. Three juveniles exhibited a significant relationship between log10 RMR and log10 mass, with individual slopes ranging from 0.42 to 1.62. Two of these exhibited a significant relationship between log10 RMR and log10 age. The remaining two juveniles and the three adults exhibited no significant relationship between RMR and body mass. With increasing size and age, RMRs of juveniles approached predicted values for adult mammals, but the large variation made it difficult to establish the precise age at which they achieved an adult-like RMR. RMRs of adults and juveniles exhibited marked seasonal changes. In juveniles, seasonal changes in RMR were limited to the annual moult, when the average RMR was 35% higher than during the rest of the year. In adults, changes in RMR were not limited to the time of the annual moult; rather, RMR was lower (by up to 50%) in the summer than during other seasons.

The ontogeny of metabolic rate and thermoregulatory capabilities of northern fur seal, Callorhinus ursinus, pups in air and water

2000 ◽  
Vol 203 (6) ◽  
pp. 1003-1016 ◽  
Author(s):  
M.J. Donohue ◽  
D.P. Costa ◽  
M.E. Goebel ◽  
J.D. Baker
Keyword(s):  
Metabolic Rate ◽  
Developmental Stages ◽  
Resting Metabolic Rate ◽  
Thermal Conductance ◽  
Open Circuit ◽  
Whole Body ◽  
Callorhinus Ursinus ◽  
Metabolic Rates ◽  
Northern Fur Seal ◽  
Fur Seal

Young pinnipeds, born on land, must eventually enter the water to feed independently. The aim of this study was to examine developmental factors that might influence this transition. The ontogeny of metabolic rate and thermoregulation in northern fur seal, Callorhinus ursinus, pups was investigated at two developmental stages in air and water using open-circuit respirometry. Mean in-air resting metabolic rate (RMR) increased significantly from 113+/−5 ml O(2)min(−)(1) (N=18) pre-molt to 160+/−4 ml O(2)min(−)(1) (N=16; means +/− s.e.m.) post-molt. In-water, whole-body metabolic rates did not differ pre- and post-molt and were 2.6 and 1.6 times in-air RMRs respectively. Mass-specific metabolic rates of pre-molt pups in water were 2.8 times in-air rates. Mean mass-specific metabolic rates of post-molt pups at 20 degrees C in water and air did not differ (16.1+/−1.7 ml O(2)min(−)(1)kg(−)(1); N=10). In-air mass-specific metabolic rates of post-molt pups were significantly lower than in-water rates at 5 degrees C (18.2+/−1.1 ml O(2)min(−)(1)kg(−)(1); N=10) and 10 degrees C (19.4+/−1.7 ml O(2)min(−)(1)kg(−)(1); N=10; means +/− s.e.m.). Northern fur seal pups have metabolic rates comparable with those of terrestrial mammalian young of similar body size. Thermal conductance was independent of air temperature, but increased with water temperature. In-water thermal conductance of pre-molt pups was approximately twice that of post-molt pups. In-water pre-molt pups matched the energy expenditure of larger post-molt pups while still failing to maintain body temperature. Pre-molt pups experience greater relative costs when entering the water regardless of temperature than do larger post-molt pups. This study demonstrates that the development of thermoregulatory capabilities plays a significant role in determining when northern fur seal pups enter the water.

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
Keyword(s):  
Body Temperature ◽  
Ground Squirrel ◽  
Environmental Temperature ◽  
Body Temperatures ◽  
Metabolic Heat ◽  
Thermoneutral Zone ◽  
Air Temperatures ◽  
The Mean ◽  
Maximum Body ◽  
Over Time

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.

Mechanisms of cold acclimatization in the cat

1963 ◽  
Vol 18 (4) ◽  
pp. 778-780 ◽  
Author(s):  
Thomas Adams
Keyword(s):  
Cold Exposure ◽  
Whole Body ◽  
Metabolic Rates ◽  
Body Temperatures ◽  
Peripheral Vascular ◽  
Air Exposure ◽  
Cold Acclimatization ◽  
Tissue Insulation ◽  
Body Heat ◽  
Internal Body

Thermoregulatory control in cats living at 25 C was compared to the regulation of body temperature in the same species after continuous whole-body cold exposure to an ambient temperature of 5 C for periods exceeding 2 months. Rectal and extremity temperatures and metabolic rates for the two groups were examined during acute (2-hr) air exposures to 23, 10, and 0 C. Cold acclimatizing mechanisms in the cat involve a redistribution of body heat at 23 C, obligating increased heat flux at the expense of elevated metabolism, an improved peripheral vascular defense (increase functional tissue insulation) during moderate cold exposure (10 C), and a greater ability to increase heat production accompanied by more labile peripheral vasomotion, during more severe cold air exposure (0 C). Although resting at 23 C, cold-acclimatized cats had lower rectal temperatures and were able to maintain higher internal body temperatures during both levels of cold stress compared to noncold-acclimatized animals. Submitted on November 1, 1962

Effect of cutaneous denervation of face and trunk on thermoregulatory responses to cold in rats

1985 ◽  
Vol 58 (2) ◽  
pp. 376-383 ◽  
Author(s):  
M. E. Heath
Keyword(s):  
Critical Temperature ◽  
Body Temperature ◽  
Heat Production ◽  
Afferent Input ◽  
Metabolic Rates ◽  
Cool Environment ◽  
Lower Critical Temperature ◽  
The Face ◽  
Regulate Body Temperature ◽  
Made In

The effect of eliminating afferent input from cutaneous thermoreceptors of the face and trunk on the ability of rats to regulate body temperature in cool environments was studied. Thermoregulatory ability in a cool environment was assessed first in a 25 degrees C environment and then during slow (20 min) and rapid (5 min) reductions of ambient temperature (Ta) to 15 degrees C by monitoring rate of heat production, rectal temperature, and skin temperature on the back, ear, and tail. These measurements were made in four rats while they were intact and during the 2 wk after cutaneous denervation. Rats were found to regulate body temperature well even after the cutaneous nerves of the trunk and face were sectioned. In eight rats the metabolic curve was determined before and 7–10 days after cutaneous denervation. Although the minimal resting metabolic rates did not differ in the two conditions, the lower critical temperature was significantly elevated from 26.8 to 28.9 degrees C and the rate of rise in metabolic rate per degrees celsius decrease in Ta was also significantly higher after cutaneous denervation. It appears that the higher rate of heat production is in compensation for an increase in the rate of heat loss in denervated rats.

Do metabolism and contour plumage insulation vary in response to seasonal energy bottlenecks in superb fairy-wrens?

2006 ◽  
Vol 54 (1) ◽  
pp. 23 ◽  
Author(s):  
Alan Lill ◽  
Jeffrey Box ◽  
John Baldwin
Keyword(s):  
Critical Temperature ◽  
Metabolic Rate ◽  
Thermal Conductance ◽  
Whole Body ◽  
Ambient Temperatures ◽  
The North ◽  
General Metabolism ◽  
Lower Critical Temperature ◽  
Heat Conservation ◽  
Low Altitude

Many small birds living at mid-to-high latitudes in the North Temperate Zone display seasonal increases in general metabolism and plumage insulation. We examined whether superb fairy-wrens at low altitude in temperate Australia, where winter is milder and the winter–spring transition less pronounced, exhibited similar adjustments. Their oxygen-consumption rate at ambient temperatures in and below their thermoneutral range was measured overnight in winter, spring and summer. Contour plumage mass was also compared in individuals caught in all seasons of the year. Resting-phase metabolic rate in the thermoneutral zone did not vary seasonally. The relationship between ambient temperature and whole-body metabolic rate below lower critical temperature differed in summer and winter, but the regression for spring did not differ from those for summer or winter. Plumage mass was greater (4.04% v. 2.64% of body mass) and calculated whole-bird wet thermal conductance lower (1.55 v. 2.24 mL O2 bird–1 h–1 °C–1) in winter than in summer. Enhanced plumage insulation could have improved heat conservation in autumn and winter. No increase in standard metabolism occurred in winter, perhaps because this season is relatively mild at low altitude in temperate Australia. However, superb fairy-wrens at 37°S operated below their predicted lower critical temperature for most of winter and the early breeding season, so they have presumably evolved as yet unidentified mechanisms for coping with the energy bottlenecks encountered then.

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