Hibernation in the Eastern Pygmy Possum, Cercartetus-Nanus (Marsupialia, Burramyidae)

1993 ◽  
Vol 41 (1) ◽  
pp. 67 ◽  
Author(s):  
F Geiser

The pattern of torpor was examined in the eastern pygmy possum, Cercartetus nanus (21 g). Animals displayed torpor regularly in the laboratory, and the occurrence of torpor increased with decreasing air temperature (T(a)). At high T(a) (18-degrees-C) animals usually exhibited daily torpor, but torpor bouts of up to 2 days were observed occasionally. The duration of torpor bouts lengthened with a lowering of T(a) and the mean bout duration at T(a) = 5-degrees-C was 17.0 +/- 2.5 days. The minimum metabolic rate (measured as rate of oxygen consumption) of torpid individuals was 0.018 +/- 0.003 mL O2 g-1 h-1, which is less than 2% of the basal metabolic rate. The body temperature (T(b)) Of torpid animals fell to a minimum of 1.3 +/- 0.4-degrees-C. These results clearly demonstrate that Cercartetus nanus is a deep hibernator.

1977 ◽  
Vol 71 (1) ◽  
pp. 205-211
Author(s):  
ELFED MORGAN

1. The mechanical power required by Nymphon for swimming at constant depth has been calculated from drag forces acting on the legs. For an adult male this was found to be 3.4 W kg. Only about 60% of this is used to support the animal's weight in water. 2. The metabolic rate fluctuates spontaneously over a tidal cycle, being greatest during the ebb-tide period. The mean rate of oxygen consumption during the animals least active phase was found to be about 0.1 μlO2 mg−1 h−1. 3. The total carbohydrate and lipid immediately available for combustion have been estimated at 4.64 and 16 μg/mg wet wt respectively. These quantities should be adequate for about 42 h periodic swimming in an adult Nymphon.


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.


1994 ◽  
Vol 42 (1) ◽  
pp. 1 ◽  
Author(s):  
F Geiser

Most heterothermic marsupials appear to display one of the two patterns of torpor that have been described in placental mammals. During shallow, daily torpor body temperature (T(b)) falls for several hours from about 35-degrees-C to values between 11 and 28-degrees-C, depending on the species, and metabolic rates fall to about 10-60% of the basal metabolic rate (BMR). In contrast during deep and prolonged torpor (hibernation), T(b) falls to about 1-5-degrees-C, metabolic rates to about 2-6% of BMR and torpor bouts last for 5-23 days. Shallow, daily torpor has been observed in the opossums (Didelphidae), the carnivorous marsupials (Dasyuridae) and the small possums (Petauridae). Daily torpor may also occur in the numbat (Myrmecobiidae) and the marsupial mole (Notoryctidae). Deep and prolonged torpor (hibernation) has been observed in the pygmy possums (Burramyidae), feathertail glider (Acrobatidae) and Dromiciops australis (Microbiotheriidae). The patterns of torpor in marsupials are paralleled by those of monotremes, placentals and even birds. These similarities in torpor patterns provide some support to the hypothesis that torpor may be plesiomorphic. However, as endothermy and torpor in birds apparently has evolved separately from that in mammals and as torpor occurrence in mammals can change within only a few generations it appears more likely that torpor in endotherms is convergent.


1982 ◽  
Vol 60 (4) ◽  
pp. 491-494 ◽  
Author(s):  
Jacques Larochelle ◽  
Jeffrey Delson ◽  
Knut Schmidt-Nielsen

Metabolic rate, body temperature, and heat dissipating mechanisms of the Black Vulture were studied under laboratory conditions. The metabolic rate (6.5 W) was close to the predicted one. The body temperature showed considerable variations with air temperature, ranging from 37.7 °C at 15 °C to 42.9 °C at 45 °C. The area of featherless skin on the head and neck changed with the body temperature, thus indicating a role in heat dissipation, and we conclude that these featherless skin areas can be adjusted according to the need for temperature regulation.


1970 ◽  
Vol 53 (2) ◽  
pp. 349-362
Author(s):  
JAMES L. HANEGAN ◽  
JAMES E. HEATH

1. Thoracic temperature in the moth, Hyalophora cecropia, is correlated with gross patterns of behaviour. 2. The animal warms up to a minimum of 34.8°C body temperature before initiating flight. The rate of warm-up is linear and the duration of the warm-up period increases with decreasing air temperature. 3. Thoracic temperature at the initiation of flight and during maintained flight remain constant at any given air temperature, however, decreases 0.25°C per °C gradient as air temperature is decreased. 4. Distribution of the maximum and minimum thoracic temperatures during active periods indicate that the animal maintains its body temperature within a favourable range. The animal uses behavioural mechanisms to maintain the thoracic temperature within this range when the body temperature reaches the limits, 33.4 and 37.8 °C. 5. The minimum thoracic temperature for flight (34.8°C) and the shade-seeking temperature (38.5°C) correspond closely to the limits predicted from the maximum-minimum distribution of thoracic temperatures. 6. The theoretical minimum and maximum rates of oxygen consumption were calculated from cooling curves and warm-up curves. Both rates increase when the gradient between body temperature and air temperature increases (air temperature is lowered, body temperature remains relatively constant). 7. Directly measured rates of oxygen consumption in flying animals increase as air temperature decreases. These values fall within the calculated maximum and minimum in all cases. 8. Oxygen consumption measured in torpid animals indicates a normal poikilothermic response, increasing with increased air temperature. The Q10 for this response is 2.25 over the range 20-30 °C. 9. A model for the regulation of body temperature in active moths is discussed.


1968 ◽  
Vol 48 (2) ◽  
pp. 427-434
Author(s):  
A. E. BRAFIELD

1. The oxygen consumption of the echiuroid Bonellia viridis has been investigated by means of a continuous-flow polarographic respirometer. 2. The general rate of oxygen consumption per unit dry weight is similar to that characteristic of polychaetes, and declines exponentially with increasing body size. 3. The rate of oxygen consumption rises in the light and falls again if darkness is restored. 4. The oxygen consumption of the isolated proboscis plus that of the isolated body region corresponds closely to that of the entire animal. 5. The oxygen consumption per unit dry weight of the proboscis is considerably higher than that of the body region. 6. The oxygen consumption of an isolated body region increases in the presence of light, but that of an isolated proboscis does not. 7. These findings are discussed in relation to the biology of the animal, observed muscular activity, and the occurrence of the pigment bonellin.


1961 ◽  
Vol 38 (2) ◽  
pp. 301-314 ◽  
Author(s):  
BODIL NIELSEN

1. In two species of Lacerta (L. viridis and L. sicula) the effects on respiration of body temperature (changes in metabolic rate) and of CO2 added to the inspired air were studied. 2. Pulmonary ventilation increases when body temperature increases. The increase is brought about by an increase in respiratory frequency. No relationship is found between respiratory depth and temperature. 3. The rise in ventilation is provoked by the needs of metabolism and is not established for temperature regulating purposes (in the temperature interval 10°-35°C). 4. The ventilation per litre O2 consumed has a high numerical value (about 75, compared to about 20 in man). It varies with the body temperature and demonstrates that the inspired air is better utilized at the higher temperatures. 5. Pulmonary ventilation increases with increasing CO2 percentages in the inspired air between o and 3%. At further increases in the CO2 percentage (3-13.5%) it decreases again. 6. At each CO2 percentage the pulmonary ventilation reaches a steady state after some time (10-60 min.) and is then unchanged over prolonged periods (1 hr.). 7. The respiratory frequency in the steady state decreases with increasing CO2 percentages. The respiratory depth in the steady state increases with increasing CO2 percentages. This effect of CO2 breathing is not influenced by a change in body temperature from 20° to 30°C. 8. Respiration is periodically inhibited by CO2 percentages above 4%. This inhibition, causing a Cheyne-Stokes-like respiration, ceases after a certain time, proportional to the CO2 percentage (1 hr. at 8-13% CO2), and respiration becomes regular (steady state). Shift to room air breathing causes an instantaneous increase in frequency to well above the normal value followed by a gradual decrease to normal values. 9. The nature of the CO2 effect on respiratory frequency and respiratory depth is discussed, considering both chemoreceptor and humoral mechanisms.


1971 ◽  
Vol 55 (3) ◽  
pp. 651-665 ◽  
Author(s):  
G. M. HUGHES ◽  
R. GAYMER ◽  
MARGARET MOORE ◽  
A. J. WOAKES

1. The O2 consumption and CO2 release of nine giant tortoises Testudo gigantea (weight range 118 g-35·5 kg) were measured at a temperature of about 25·5°C. Four European tortoises Testudo hermanni (weight range 640 g-2·16 kg) were also used. The mean RQ values obtained were 1·01 for T. gigantea and 0·97 for T. hermanni. These values were not influenced by activity or size. 2. The data was analysed by plotting log/log regression lines relating body weight to O2 consumption. Both maximum and minimum metabolic rates recorded for each individual T. gigantea showed a negative correlation with body weight. For active rates the relation was O2 consumption = 140·8W0·97, whereas for inactive animals O2 consumption = 45·47W0·82. 3. The maximum rates were obtained from animals that were observed to be active in the respirometer and the minimum rates from animals that remained quiet throughout. The scope for activity increased with body size, being 82 ml/kg/h for animals of 100 g and 103 ml/kg/h for 100 kg animals. The corresponding ratio between maximum and minimum rates increases from about 2 to 6 for the same weight range. 4. Values for metabolic rate in T. hermanni seem to be rather lower than in T. gigantea. Analysis of the relative proportion of the shell and other organs indicates that the shell forms about 31% of the body weight in adult T. hermanni but only about 18% in T. gigantea of similar size. The shell is not appreciably heavier in adult T. gigantea (about 20%). 5. Data obtained for inactive animals is in good agreement with results of other workers using lizards and snakes. Previous evidence suggesting that chelonians show no reduction in metabolic rate with increasing size is not considered to conflict with data obtained in the present work.


1908 ◽  
Vol 28 ◽  
pp. 66-84 ◽  
Author(s):  
Sutherland Simpson

SUMMARYThe body-temperature of the following fishes, crustaceans, and echinoderms has been examined and compared with the temperature of the water in which they live:—Cod-fish (Gadus morrhua), ling (Molva vulgaris), torsk (Brosmius brosme), coal-fish or saithe (Gadus virens), haddock (Gadus œgelfinus), flounder (Pleuronectes flesus), smelt (Osmerus eperlanus), dog-fish (Scyllium catulus), shore crab (Carcinus mœnas), edible crab (Cancer pagurus), lobster (Homarus vulgaris), sea-urchin (Echinus esculentus), and starfish (Asterias rubens). The minimum, maximum, and mean temperature difference for each species are given in the following table:—The excess of temperature is most evident in the larger specimens. This is well shown in the case of the coal-fish, where in the adult it was 0°·7 C., and in the great majority (11 out of 12) of the young of the first year, 0°·0 C. The body-weight and the conditions under which the fish are captured probably form the most important factors in determining the temperature difference.In 14 codfish, where the rectal, blood, and muscle temperatures were recorded in the same individual, it was found to be highest in the muscle and lowest in the rectum, the mean temperature difference being 0°·46 C. for the muscle, 0°·41 C for the blood, and 0°·36 C. for the rectum.


2000 ◽  
Vol 203 (12) ◽  
pp. 1809-1815
Author(s):  
D.A. Scholnick ◽  
T.T. Gleeson

During recovery from even a brief period of exercise, metabolic rate remains elevated above resting levels for extended periods. The intensity and duration of exercise as well as body temperature and hormone levels can influence this excess post-exercise oxygen consumption (EPOC). We examined the influence of activity before exercise (ABE), commonly termed warm-up in endotherms, on EPOC in the desert iguana Dipsosaurus dorsalis. The rate of oxygen consumption and blood lactate levels were measured in 11 female D. dorsalis (mass 41.1 +/− 3.0 g; mean +/− s.e.m.) during rest, after two types of ABE and after 5 min of exhaustive exercise followed by 60 min of recovery. ABE was either single (15 s of maximal activity followed by a 27 min pause) or intermittent (twelve 15 s periods of exercise separated by 2 min pauses). Our results indicate that both single and intermittent ABE reduced recovery metabolic rate. EPOC volumes decreased from 0.261 to 0.156 ml of oxygen consumed during 60 min of recovery when lizards were subjected to intermittent ABE. The average cost of activity (net V(O2) during exercise and 60 min of recovery per distance traveled) was almost 40 % greater in lizards that exercised without any prior activity than in lizards that underwent ABE. Blood lactate levels and removal rates were greatest in animals that underwent ABE. These findings may be of particular importance for terrestrial ectotherms that typically use burst locomotion and have a small aerobic scope and a long recovery period.


Sign in / Sign up

Export Citation Format

Share Document