Energetics and geometry of huddling in small mammals.

Huddling in small mammals appears as an efficient response to low ambient temperatures with important consequences in thermoregulatory energy savings. These energy savings have been ascribed to a decrease in the exposed area in relation to the animal's volume. It has been proposed that during huddling reductions in the exposed area and in the metabolic rate are equal functions of the number of grouped individuals with a common exponent of -1/3. However, reported data shows a great variability of this exponent. In this paper we present a geometrical and energetic analysis on several huddling efficiencies in small mammals and in geometric bodies. Our theoretical analysis shows a variability in the efficiency of huddling, depending on the morphological characteristics of the geometric bodies. At the same time original and literature information show an analogous interspecific variability in small mammals. Finally, a general mathematical expression is proposed which represents and explains the energetic and geometric specific variations of huddling in small mammals.

[1]  L. C. Contreras.  Bioenergetics of huddling: test of a psycho-physiological hypothesis , 1984 .

[2]  M. Gębczyński.  Social regulation of body temperature in the bank vole , 1969 .

[3]  Z. Gębczyńska.  Bioenergetics of a root vole population , 1970 .

[4]  John A. Sealander,et al.  The Relationship of Nest Protection and Huddling to Survival of Peromyscus at Low Temperature , 1952 .

[5]  A. Górecki.  Metabolic rate and energy budget in the bank vole , 1968 .

[6]  W. Karasov.  Wintertime Energy Conservation by Huddling in Antelope Ground Squirrels (Ammospermophilus leucurus) , 1983 .

[7]  J. Layne.  Nest-Building Behavior in Three Species of Deer Mice, Peromyscus , 1969 .

[8]  G. Barrett,et al.  Importance of Social Grouping on Bioenergetics of the Golden Mouse, Ochrotomys nuttalli , 1981 .

[9]  O. Pearson,et al.  The Rate of Metabolism of Some Small Mammals , 1947 .

[10]  D. Makihara,et al.  Metabolic and thermoregulatory consequences of social behaviors between Microtus townsendii. , 1987, Comparative biochemistry and physiology. A, Comparative physiology.

[11]  Anna Fedyk,et al.  Social thermoregulation in Apodemus flavicollis (Melchior, 1834) , 1971 .

[12]  G. Lynch,et al.  Influence of Ambient Temperature, Nest Availability, Huddling, and Daily Torpor on Energy Expenditure in the White-Footed Mouse Peromyscus Leucopus , 1982, Physiological Zoology.

[13]  P. Withers,et al.  The effect of huddling on thermoregulation and oxygen consumption for the naked mole-rat , 1980 .

[14]  R. Belknap,et al.  Bioenergetic benefits of huddling by deer mice (Peromyscus maniculatus). , 1986, Comparative biochemistry and physiology. A, Comparative physiology.

[15]  C. Herreid,et al.  Thermal conductance in birds and mammals. , 1967, Comparative biochemistry and physiology.

[16]  P. Morrison.  An automatic manometric respirometer. , 1951, The Review of scientific instruments.