Temperature regulation in the little pocket mouse, Perognathus longimembris

Chew, Robert M.; Lindberg, R. G.; Hayden, Page

doi:10.1016/0010-406x(67)90447-1

Cited by 37 publications

(15 citation statements)

References 17 publications

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“…This was about three times basal metabolism (0.13 kcaljg ·day) measured at thermal neutrality (31.5°C-34.50C) for this species (Chew et al 1967). This was about three times basal metabolism (0.13 kcaljg ·day) measured at thermal neutrality (31.5°C-34.50C) for this species (Chew et al 1967).…”

Section: Resultsmentioning

confidence: 63%

Selection of High Temperatures for Hibernation by the Pocket Mouse, Perognathus Longimembris: Ecological Advantages and Energetic Consequences

French¹

1976

Ecology

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Daily metabolism was calculated from food consumption in pocket mice, Perognathus longimembris, at s•c, 1s•c, and 3PC. At temperatures below thermal neutrality for this species, daily metabolism was related to the amount of time the mice spent in torpor.Ambient temperature has no net effect on the minimum energy expenditure during a typical 5-mo hibernation season. Once an animal has accumulated a food store of = 130 g of millet seeds, it has the minimum energy necessary to hibernate at any environmental temperature. Such temperature compensation results from the complex effects of temperature on ( 1) the ratio of time of euthermy to time of torpor, (2) the energetic cost per hour of torpor, (3) the energetic cost per hour of euthermy, and ( 4) the energetic cost of arousal from torpor. The amount of time spent in torpor was inversely dependent on the food supply, indicating that euthermia is preferred even during the hibernation season. Mice also maximize the time of euthermia by selecting high environmental temperatures at all times of the year. Torpor probably occurs naturally only during the winter when the highest temperatures available to the mice are below thermal neutrality. The maximization of the time of euthermia reduces the chances of freezing during hibernation and enhances the animal's ability to escape from predators.

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Section: Resultsmentioning

confidence: 63%

Selection of High Temperatures for Hibernation by the Pocket Mouse, Perognathus Longimembris: Ecological Advantages and Energetic Consequences

French¹

1976

Ecology

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“…1950, Morrison and Ryser 1951, McNab and Morrison 1963, Hayward 1965, Tucker 1965, Chew, Lindberg, and Hayden 1967, Packard 1968, and Wunder 1970 Kleiber ( 1972) has recently pointed out, however, that it is actually Fourier's law of heat flow which more accurately describes the situation. (For rodents see: Scholander et a!.…”

Section: Resultsmentioning

confidence: 99%

Energy‐Exchange Analysis of the Belding Ground Squirrel and Its Habitat

Morhardt¹,

Gates²

1974

Ecological Monographs

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A hstmct. An analysis is made of energy exchange between Belding ground squirrels ( Citellu.1 heldin;;i heldingi) and the microhabitats which they occupy during their annual summer period of activity. A natural population was observed. and the microclimates of six different types of microhabitats which the squirrels typically occupied are quantitatively described. Methods are derived for calculating the average radiation absorbed by a geometric model which is used to represent the squirrel at different orientations to the sun. The average absorbed radiation is plotted as a function of air temperature in climate diagrams that describe the thermal conditions occurring hourly in the microhabitats on clear. partly cloudy. and stormy days.The physiological and physical properties of the animals which affect energy exchange were measured in an open-flow metabolic apparatus. Body temperature, surface temperature, metabolic rate rate of evaporative water loss. and conductance are expressed as functions of effective ambient temperature. The capabilities of the squirrels for maintaining energy balance under extreme combinations of air temperature, absorbed radiation, and wind speed were calculated from physiological data by using an energy-budget equation. and are expressed on climate diagrams similar to those describing the thermal environments of the microhabitats. By comparing a climate diagram for a microhabitat with that for a squirrel, one can determine whether or not the squirrel is capable of maintaining thermal equilibrium in that microhabitat during any hour of the day. The net gain or loss of energy can be calculated from the climate diagrams for an animal in an environment in which it cannot maintain thermal equilibrium. The rate of change in body temperature resulting from energy imbalance is discussed in terms of its significance for animals occupying thermally unsuitable habitats.A method is proposed for comparing the nearly blackbody radiation environment of a metabolic chamber to complex natural thermal environments. With this technique it is possible to use laboratory data taken for a species at different ·blackbody ambient temperatures to estimate the physiological responses of that species to any natural environment where the wind speed. air temperature. and absorbed radiation are known.Exchange of energy between an animal and its surroundings occurs continuously and is influenced by properties of both the animal and the microhabitat. To a certain extent an animal is able to regulate the exchange of energy at its surface either behaviorally through the selection of an appropriate microhabitat. or physiologically by changes of metabolic rate, evaporative water loss, or effective insulation. A continuous balance between an animal's energy income and outflow is essential for precise temperature regulation. A net gain of energy will result in an increase in body temperature. whereas a net loss will result in , . 'Present address: Harland Bartholomew and Associates, 165 North Meramec Ave., St. Louis, Mo. 631...

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“…[These factors are derived from the available metabolic data on P.longimembris (Chew et al 1967), D. merriami (Carpenter 1966), and D. microps (Carpenter's data for D. agilis, which is similar in weight to D. microps) .] The relative effects of cold weather are more profound for smaller species in this regard.…”

Section: Discussionmentioning

confidence: 99%

“…But an important strategy of energy conservation used by P. longimembris is that of physiological dormancy, or torpidity (Bartholomew and Cade 1957), in which metabolic rate may drop to 3% of the resting rate (Chew et al 1967). But an important strategy of energy conservation used by P. longimembris is that of physiological dormancy, or torpidity (Bartholomew and Cade 1957), in which metabolic rate may drop to 3% of the resting rate (Chew et al 1967).…”

Section: Energy Conservation Through Dormancymentioning

confidence: 99%

Daily and Seasonal Patterns of Activity and Energetics in a Heteromyid Rodent Community

Kenagy

1973

Ecology

177

140

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Dipodomys microps, D. merriami, and Perognathus longimembris spend most of their lives solitarily and in the ground, coming out onto the surface only at night and foraging for as little as an hour. However, they are active within their burrows throughout the day, seldom remaining motionless for more than half an hour at a time during the warmer parts of the year. All three species rest at positions in their burrows which are generally at the nearest of available temperatures to the lower end of thermal neutrality, but not warmer than 30° C. To do this, they occupy different depths at different seasons and in some cases different times of day. Daily vertical movements are most common in P. longimembris, because it maintains tunnels as near as 1 em from the surface, where daily fluctuations in temperature are profound. In late fall, winter, and early spring all three species occupy nests, which serve to reduce metabolic expenditure.Energetic strategies differ interspecifically in relation to differences in body weight among the species: D. microps (56 g), D. merriami (35 g), and P. longimembris (7 g). The amount of surface activity in the populations and the frequency of movement measured in individuals decrease during colder parts of the year. This decrease is most apparent in the smaller species, and is related to the decreasing success at foraging later in the season and the increasing costs of metabolism at colder temperatures. Surface activity in D. microps and D. merriami continues throughout the year, at temperatures measured as low as -19o C. However, for P. longimembris the costs of foraging in winter usually far outweigh the yield, and the mice become continuously fossorial for up to 5 months of the year, living on seeds that they have cached in their burrows, and spending a great deal of time in dormancy.Seasonal cycles of body weight and reproduction are not synchronous in D. microps and D. merriami, because of differences in diet and foraging behavior. Dipodomys merriami, which is primarily a seed eater, requires the green vegetation of annual plants to reproduce, and therefore this species increases body weight and reproduces at sporadic intervals according to the unpredictable availability of annuals. Dipodomys microps, however, reproduces in a brief, annually consistent period because leaves of perennial shrubs are its primary yearround food and water resource. This larger kangaroo rat forages over a smaller area for leaves than D. merriami does for seeds; but D. merriami runs 50% faster, which should compensate for the cost of moving greater distances. Dipodomys microps is most active during the first part of the night, but D. merriami becomes more active during the course of the night as the activity of D. microps decreases. Height and breadth of burrow hillocks and height of shrubs on hillocks were significantly larger for D. microps than the other species, but height of burrow hillo:ks and shrubs on them did not differ between D. merriami and P. longimembris. Perognathus longimembris resembles D...

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Temperature regulation in the little pocket mouse, Perognathus longimembris

Cited by 37 publications

References 17 publications

Selection of High Temperatures for Hibernation by the Pocket Mouse, Perognathus Longimembris: Ecological Advantages and Energetic Consequences

Selection of High Temperatures for Hibernation by the Pocket Mouse, Perognathus Longimembris: Ecological Advantages and Energetic Consequences

Energy‐Exchange Analysis of the Belding Ground Squirrel and Its Habitat

Daily and Seasonal Patterns of Activity and Energetics in a Heteromyid Rodent Community

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