Summary
Rates of metabolism and evaporative water loss were investigated inSpermophilus beecheyi. Special attention was paid to the influence of the micro-climate of the animal's burrow on these parameters.
Metabolic rate as measured by oxygen consumption is 25 per cent below that predicted from body weight. A new hypothesis is advanced to account for this commonly observed phenomenon in fossorial rodents. In summer, there is an overlap of the region of thermal neutrality and temperature in the animal's burrow but winter burrow temperatures are below thermal neutrality.
Evaporative cooling accounts for approximately 20 per cent of the total heat loss in thermal neutrality and at low humidity. Minimization of this heat loss avenue by high humidities did not result in an increase of body temperature or metabolic rate, therefore the dimension of the thermal neutral zone is independent of ambient humidity.
By indirect means, evaporative water loss was partitioned into 37 per cent from cutaneous sources and 63 per cent from pulmonary sources. A direct relationship was found between ambient water vapor pressure and evaporative water loss.
The relationship between body and ambient temperature was investigated by telemetry. At lower temperatures, the former is maintained at constant levels, but hyperthermia develops above 30 ° C.
Similar content being viewed by others
References
Bartholomew, G. A., Rainey, M.: Regulation of body temperature in the Rock Hyrax,Heterohyrax brucei. J. Mammal.52, 81–95 (1971).
Bernstein, M. H.: Cutaneous and respiratory evaporation in painted quail,Excalfactoria chinensis, during ontogeny of thermoregulation. Comp. Biochem. Physiol.38A, 463–467 (1971).
Brody, S.: Bioenergetics and growth. New York: Reinhold 1945.
Chew, R. M.: The skin and respiratory water losses ofPeromyscus maniculatus sonoriensis. Ecology36, 463–467 (1955).
Chew, R. M., Damman, A. E.: Evaporative water loss of small vertebrates, as measured with an infrared analyzer. Science133, 384–385 (1961).
Coulombe, H. N.: Physiological and physical aspects of temperature regulation in the Burrowing OwlSpeotyto cunicularia. Comp. Biochem. Physiol.35, 307–337 (1970).
Durrant, S. D., Hansen, R. M.: Distribution patterns and phylogeny of some western ground squirrels. System. Zool.3, 82–85 (1954).
Fitch, H. S.: Ecology of the California ground squirrel on grazing lands. Amer. Midl. Nat.39, 513–596 (1948).
Grinnell, J., Dixon, J.: Natural history of the ground squirrels of California. Bull. California State Comm. Hort.7, 597–708 (1918).
Hall, E. R., Kelson, K. R.: The mammals of North America, vol.2. New York: Ronald Press 1959.
Hall, F. G.: Hemoglobin and oxygen: Affinities in seven species of Sciuridae. Science148, 1350–1351 (1965).
Hayward, J. S.: Abnormal concentrations of respiratory gases in rabbit burrows. J. Mammal.47, 723–724 (1966).
Hudson, J. W.: The role of water in the biology of the Antelope ground squirrelCitellus leucurus. Univ. California Publ. Zool.64, 1–56 (1962).
Hudson, J. W., Bartholomew, G. A.: Terrestrial animals in dry heat: Estivators. In: Handbook of physiology, section 4, Adaptation to the environment (edited by Dill, D. B.), chap. 34. Washington: American Physiological Society 1964.
Hudson, J. W., Deavers, D. R., Bradley, S. R.: A comparative study of temperature regulation in ground squirrels with special reference to the desert species. In: Comparative physiology of desert animals, ed. G. H. O. Maloiy. 31st Symposium Zoological Society of London. London: Academic Press (in press).
Hutchinson, J. C. D.: Evaporative cooling in fowls. J. Agric. Sci. Camb.45, 48–59 (1954).
Kawata, S., Omori, Y.: An investigation of thermocouple psychrometer. J. Phys. Soc. Tokyo8, 768 (1953).
Kennerly, T. E., Jr.: Microenvironmental conditions of the pocket gopher burrow. Texas J. Sci.16, 395–441 (1964).
King, J. R., Farner, D. S.: Energy metabolism, thermoregulation and body temperature. In: Biology and comparative physiology of birds, vol. 2, p. 215–288, ed. A. J. Marshall. London: Academic Press 1961.
Lasiewski, R. C., Acosta, A. L., Bernstein, M. H.: Evaporative water loss in birds — 1. Characteristics of the open flow method of determination, and their relation to estimates of thermoregulator ability. Comp. Biochem. Physiol.19, 445–457 (1966).
Linsdale, J. M.: The California ground squirrel, 475 pp. Berkeley-Los Angeles: University of California Press 1946.
McAdams, W. H.: Heat transmission, third edition, 532 pp. New York: McGraw-Hill 1954.
MacMillen, R. E., Lee, A. K.: Energy metabolism and pulmooutaneous water loss of Australian hopping mice. Comp. Biochem. Physiol.35, 355–369 (1970).
McNab, B. K.: The metabolism of fossorial rodents: A study of convergence. Ecology47, 712–733 (1970).
McNab, B. K.: Body weight and the energetics of temperature regulation. J. exp. Biol.53, 329–348 (1970).
Morrison, P. R.,et al.: Studies on the physiology of the masked shrewSorex cinereus. Physiol. Zool.32, 256–271 (1959).
Proctor, J. W., Studier, E. H.: Effects of ambient temperature and water vapor pressure on evaporative water loss inMyotis lucifugus. J. Mammal.51, 799–804 (1970).
Salt, G. W.: Respiratory evaporation in birds. Biol. Rev.39, 113–136 (1964).
Schmidt-Nielsen, K.: Desert animals: physiological problems of heat and water, 277 pp. London: Oxford University Press 1964.
Schmidt-Nielsen, K., Larimer, J. L.: Oxygen dissociation curves of mammalian blood in relation to body size. Amer. J. Physiol.195, 424–428 (1958).
Schmidt-Nielsen, K.,et al.: The jack rabbit-a study in its desert survival. Hvalradets Skrifter48, 125–142 (1965).
Stahl, W. R.: Scaling of respiratory variables in mammals. J. appl. Physiol.22, 453–460 (1967).
Studier, E. H., Procter, J. W.: Respiratory gases in burrows ofSpermophilus tridecemlineatus. J. Mammal.52, 631–633 (1971).
Stupfel, M., Geloso, J. P.: Etude des pertes d'eau par les voies cutanée et respiratoire du Rat blanc non anéthesié, placé dans une atmosphère sèche normale et dans une atmosphère sèche renfermant 10 percent de gaz carbonique. C. R. Acad. Sci. (Paris)248, 740–742 (1959).
Strumwasser, F.: Factors in the pattern, timing, and predictability of hibernation in the squirrelCitellus beecheyi. Amer. J. Physiol.196, 8–14 (1959).
Tomich, P. Q.: The annual cycle of the California ground squirrel.Citellus beecheyi. Univ. California Publ. Zool.65, 213–282 (1962).
Weast, R. C. (ed.): Handbook of chemistry and physics, 48th edition. Cleveland: The Chemical Rubber Company 1967.
Author information
Authors and Affiliations
Additional information
This paper is part of a dissertation submitted in partial fulfillment of the requirement for the Ph.D. at University of California, Irvine.
The work was supported by grants from the Society of the Sigma Xi and the University of California, Irvine Patent Fund to the author and National Science Foundation Grant No. GB-17833 to Richard E. MacMillen.
I thank Dr. MacMillen for his guidance in all phases of the work, and Drs. G. A. Bartholomew and P. W. Rundel for their helpful comments on the manuscript.
Rights and permissions
About this article
Cite this article
Baudinette, R.V. Energy metabolism and evaporative water loss in the California ground squirrel. J. Comp. Physiol. 81, 57–72 (1972). https://doi.org/10.1007/BF00693550
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00693550