, Volume 12, Issue 4, pp 383–412 | Cite as

Adaptations for leaf eating in the great basin kangaroo rat, Dipodomys microps

  • G. J. Kenagy


Dipodomys microps forages in saltbush (Atriplex confertifolia), gathering the leaves into its external check pouches and returning them to the burrow to be cached or eaten. The leaves are available throughout the year and contain 50–80% water. D. microps can survive on these leaves in the laboratory without other food or water, but it is unusual among kangaroo rats in that it quickly succumbs when placed on a diet of air-dried seeds without water or succulent plant material. Its mean urine concentration on the seed diet was 2827 mOsm/l, which is lower than any previously reported for the genus. On the other hand, D. merriami, which occurs with D. microps and is well known as a seed specialist, cannot survive on the saltbush leaves, although it is capable of living on a seed diet without water or green vegetation.

D. microps is behaviorally and morphologically specialized for exploiting the unusual leaves of A. confertifolia. The leaves are higher in electrolyte content than the leaves of most plants; but the electrolytes, which are most highly concentrated on the leaf surfaces, apparently serve in the maintenance of water balance in the leaves. D. microps does not usually consume saltbush leaves in toto, but rather uses its unique, chisel-shaped lower incisors to shave off the outer tissue from both sides of the leaf, and then consumes the inner tissue. Sodium concentration with respect to water in the eaten tissue was only 3% that of the discarded shavings, and the specialized photosynthetic parenchyma which is eaten is high in starch content.

The highly divergent dietary habits of D. microps should serve to minimize competition with its granivorous congeners. Some of the present limits to the geographic distribution of D. microps are a reflection of its reliance on the leaves of perennial shrubs throughout the year; but where its does occur, D. microps should be independent of the unpredictable availability of ephemeral annuals.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Allred, D.M., Beck, D.E.: Range movement and dispersal of some rodents at the Nevada Atomic Test Site. J. Mammal. 44, 190–200 (1963).Google Scholar
  2. Anderson, A.O., Allred, D.M.: Kangaroo rat burrows at the Nevada test site. Gt. Basin Nat. 24, 93–101 (1964).Google Scholar
  3. Axelrod, D.I.: Evolution of desert vegetation in western North America. Carnegie Inst. Wash. Pub. 590, 215–306 (1950).Google Scholar
  4. Bartholomew, G.A., Caswell, H.H.: Locomotion in kangaroo rats and its adaptive significance. J. Mammal. 32, 155–169 (1951).Google Scholar
  5. Beadle, N.C.W., Whalley, R.D.B., Gibson, J.B.: Studies in halophytes II. Analytic data on the mineral constituents of three species of Atriplex and their accompanying soils in Australia. Ecology 38, 340–344 (1957).Google Scholar
  6. Beatley, J.C.: Dependence of desert rodents on winter annuals and precipitation. Ecology 50, 721–724 (1969).Google Scholar
  7. Benson, S.B., Borell, A.E.: Notes on the life history of the red tree mouse, Phenacomys longicaudus. J. Mammal. 12, 226–233 (1931).Google Scholar
  8. Bernstein, R.E.: Potassium and sodium balance in mammalian red cells. Science 120, 459–460 (1954).Google Scholar
  9. Boynton, J.E., Nobs, M.A., Björkman, O., Pearcy, R.W.: Hybrids between Atriplex species with and without B-carboxylation photosynthesis. Leaf anatomy and ultrastructure. Carnegie Inst. Year Book 69, 629–632 (1971).Google Scholar
  10. Bradley, W.G., Mauer, R.A.: Reproduction and food habits of Merriam's kangaroo rat, Dipodomys merriami. J. Mammal. 52, 497–507 (1971).Google Scholar
  11. Carpenter, R.E.: A comparison of thermoregulation and water metabolism in the kangaroo rats Dipodomys agilis and Dipodomys merriami. U. Cal. Publ. Zool. 78, 1–36 (1966).Google Scholar
  12. Chapman, V.J.: Salt marshes and salt deserts of the world, 392 p. New York: Interscience Pub. 1960.Google Scholar
  13. Chess, T., Chew, R.M.: Weight maintenance of the desert woodrat (Neotoma lepida) on some natural foods. J. Mammal. 52, 193–195 (1971).Google Scholar
  14. Church, R.L.: Evaporative water loss and gross effects of water privation in the kangaroo rat, Dipodomys venustus. J. Mammal. 50, 514–523 (1969).Google Scholar
  15. Csuti, B.A.: Karyotypes of kangaroo rats from southern California. J. Mammal. 52, 202–206 (1971).Google Scholar
  16. Culbertson, A.E.: Observations on the natural history of the Fresno kangaroo rat. J. Mammal. 27, 189–203 (1946).Google Scholar
  17. Dale, F.H.: Variability and environmental responses of the kangaroo rat, Dipodomys heermanni saxatilis. Amer Mid. Nat. 22, 703–731 (1939).Google Scholar
  18. Eisenberg, J.F.: The behavior of heteromyid rodents. U. Cal. Publ. Zool. 69, 1–100 (1963).Google Scholar
  19. Fitch, H.S.: Habits and economic relationships of the Tulare kangaroo rat. J. Mammal. 29, 5–35 (1948).Google Scholar
  20. Getz, L.L.: Relationship between ambient temperature and respiratory water loss of small mammals. Comp. Biochem. Physiol. 24, 335–342 (1968).Google Scholar
  21. Grinnell, J.: Revised list of the species in the genus Dipodomys. J. Mammal. 2, 94–97 (1921).Google Scholar
  22. Grinnell, J.: A geographic study of the kangaroo rats of California. U. Cal. Publ. Zool. 24, 1–124 (1922).Google Scholar
  23. Grinnell, J.: Habitat relations of the giant kangaroo rat. J. Mammal. 13, 305–320 (1932).Google Scholar
  24. Hall, E.R.: Mammals of Nevada, 710 p. Berkeley-Los Angeles: Univ. of Calif. Press 1946.Google Scholar
  25. Hall, E.R., Dale, F.H.: Geographic races of the kangaroo rat, Dipodomys microps. Occas. Papers Mus. Zool. Louisiana State Univ. 4, 47–63 (1939).Google Scholar
  26. Hall, E.R., Kelson, K.R.: The mammals of North America, 1083 p. New York: Ronald Press 1959.Google Scholar
  27. Hardy, R.: The influence of types of soil upon the local distribution of some mammals in southwestern Utah. Ecol. Monogr. 15, 71–108 (1945).Google Scholar
  28. Hatch, M.D., Slack, C.R.: Photosynthetic CO2-fixation pathways. Ann. Rev. Plant. Physiol. 21, 141–162 (1970).Google Scholar
  29. Hawbecker, A.C.: The burrowing and feeding habits of Dipodomys venustus. J. Mammal. 21, 388–396 (1940).Google Scholar
  30. Howell, A.B., Gersh, I.: Conservation of water by the rodent Dipodomys. J. Mammal. 16, 1–9 (1935).Google Scholar
  31. Hudson, J.W., Rummel, J.A.: Water metabolism and temperature regulation of the primitive heteromyids, Liomys salvani and Liomys irroratus. Ecology 47, 345–354 (1966).Google Scholar
  32. Jennings, D.H.: Halophytes, succulence and sodium in plants—a unified theory. New Phytologist 67, 899–911 (1968).Google Scholar
  33. Johnson, W.E., Selander, R.K.: Protein variation and systematics in kangaroo rats (genus Dipodomys). Syst. Zool. 20, 377–405 (1971).Google Scholar
  34. Jorgensen, C.D.: Spatial and time distribution of Dipodomys microps occidentalis within distinct plant communities. Ecology 44, 183–187 (1963).Google Scholar
  35. Kearney, T.H., Briggs, L.J., Shantz, H.L., McLane, J.W., Piemeisel, R.L.: Indicator significance of vegetation in Tooele Valley, Utah. J. Agric. Res. 1, 365–417 (1914).Google Scholar
  36. Kenagy, G.J.: Saltbush leaves: excision of hypersaline tissue by a kangaroo rat. Science 178, 1094–1096 (1972).Google Scholar
  37. Kenagy, G.J.: Daily and seasonal patterns of activity and energetics in a heteromyid rodent community. Ecology (in press, 1973).Google Scholar
  38. Kenagy, G.J., Smith, C.B.: Radioisotopic measurement of depth and determination of temperatures in burrows of heteromyid rodents. Proc. Third National Symp. Radioecology (in press, 1972).Google Scholar
  39. Laetsch, W.M.: Chloroplast specialization in dicotyledons possessing the C4-Dicarboxylic acid pathway of photosynthetic CO2 fixation. Amer. J. Bot. 55, 875–883 (1968).Google Scholar
  40. Landry, S.O.: The rodentia as omnivores. Quart. Rev. Biol. 45, 351–372 (1970).Google Scholar
  41. Lidicker, W.Z.: An analysis of intraspecific variation in the kangaroo rat Dipodomys merriami. U. Cal. Publ. Zool. 67, 125–218 (1960).Google Scholar
  42. MacMillen, R.E.: Population ecology, water relations, and social behavior of a southern California semidesert rodent fauna. U. Cal. Publ. Zool. 71, 1–66 (1964).Google Scholar
  43. Merriam, C.H.: New and little known kangaroo rats of the genus Perodipus. Proc. Biol. Soc. Wash. 17, 139–145 (1904).Google Scholar
  44. Miller, A.H., Stebbins, R.C.: The lives of desert animals in Joshua Tree National Monument, 452 p. Berkeley-LosAngeles: Univ. of Calif. Press 1964.Google Scholar
  45. Mullen, R.K.: Energy metabolism and body water turnover rates of two species of free-living kangaroo rats, Dipodomys merriami and Dipodomys microps. Comp. Biochem. Physiol. 39A, 379–390 (1971).Google Scholar
  46. Munz, P.A., Keck, D.D.: A California flora, 1681 p. Berkeley-Los Angeles: Univ. of Calif. Press 1963.Google Scholar
  47. Osmond, B.: Oxalates and ionic equilibria in Australian saltbushes (Atriplex). Nature (Lond.) 198, 503–504 (1963).Google Scholar
  48. Osmond, C.B., Lüttge, U., West, K.R., Pallaghy, C.K., Shacher-Hill, B.: Ion absorption in Atriplex leaf tissue II. Secretion of ions into epidermal bladders. Aust. J. biol. Sci. 22, 797–814 (1969).Google Scholar
  49. Quay, W.B.: The anatomy of the diastemal palate in microtine rodents. Misc. Publ. Mus. Zool. Univ. Mich. 86 (1954).Google Scholar
  50. Reynolds, H.G.: The ecology of the Merriam kangaroo rat (Dipodomys merriami Mearns) on the grazing lands of southern Arizona. Ecol. Monogr. 28, 111–127 (1958).Google Scholar
  51. Reynolds, H.G.: Life history notes on Merriam's kangaroo rat in southern Arizona. J. Mammal. 41, 48–58 (1960).Google Scholar
  52. Richter, C.P., Mosier, D.H.: Maximum sodium chloride intake and thirst in domesticated and wild Norway rats. Amer. J. Physiol. 176, 213–222 (1954).Google Scholar
  53. Rosenzweig, M.L., Sterner, P.W.: Population ecology of desert rodent communities: body size and seed-husking as bases for heteromyid coexistence. Ecology 51, 217–224 (1970).Google Scholar
  54. Rosenzweig, M.L., Winakur, J.: Population ecology of desert rodent communities: habitats and environmental complexity. Ecology 50, 558–572 (1969).Google Scholar
  55. Sampson, A.W., Jespersen, B.S.: California range brushlands and browse plants. California Agricultural Experiment Station Extension Service Manual 33, 162p. (1963).Google Scholar
  56. Schmidt-Nielsen, B., Schmidt-Nielsen, K.: Evaporative water loss in desert rodents in their natural habitat. Ecology 31, 75–85 (1950).Google Scholar
  57. Schmidt-Nielsen, B., Schmidt-Nielsen, K., Brokaw, A., Schneiderman, H.: Water conservation in desert rodents. J. cell. comp. Physiol. 32, 331–360 (1948).Google Scholar
  58. Schmidt-Nielsen, K.: Desert animals: physiological problems of heat and water, 277 p. London: Oxford Univ. Press 1964.Google Scholar
  59. Schmidt-Nielsen, K., Jackson, D.C.: Countercurrent heat exchange in the respiratory passages. Science 144, 567 (1964).Google Scholar
  60. Setzer, H.W.: Subspeciation in the kangaroo rat, Dipodomys ordii. Univ. Kansas Publ. Mus. Nat. Hist. 1, 473–573 (1949).Google Scholar
  61. Shaw, W.T.: The ability of the giant kangaroo rat as a harvester and storer of seeds. J. Mammal. 15, 275–286 (1934).Google Scholar
  62. Tappe, D.T.: Natural history of the Tulare kangaroo rat. J. Mammal. 22, 117–148 (1941).Google Scholar
  63. Tosteson, D.C.: Active transport, genetics, and cellular evolution. Fed. Proc. 22, 19–26 (1963).Google Scholar
  64. Vorhies, C.T., Taylor, W.P.: Life history of the kangaroo rat Dipodomys spectabilis spectabilis. U.S.D.A. Bull. 1091, 1–40 (1922).Google Scholar
  65. Wallace, A., Hale, V.Q., Kleinkopf, G.E., Huffaker, R.C.: Carboxydismutase and phosphoenolpyruvate carboxylase activities from leaves of some plant species from the northern Mojave and southern Great Basin Deserts. Ecology 52, 1093–1095 (1971).Google Scholar
  66. West, K.R.: The anatomy of Atriplex leaves, p. 11–15. In: R. Jones, Ed., The biology of Atriplex. Canberra, Australia: Commonwealth Scientific and Industrial Research Organization 1970.Google Scholar
  67. White, L.D., Allred, D.M.: Range of kangaroo rats in areas affected by atomic detonations. Proc. Utah Acad. Sci., Arts, Letters 38, 101–110 (1961).Google Scholar
  68. Wilson, A.D.: The value of Atriplex (saltbush) and Kochia (bluebush) species as food for sheep. Aust. J. Agric. Res. 17, 146–153 (1966a).Google Scholar
  69. Wilson, A.D.: The intake and excretion of sodium by sheep fed on species of Atriplex (saltbush) and Kochia (bluebush). Aust. J. Agric. Res. 17, 155–163 (1966b).Google Scholar
  70. Wood, A.E.: Evolution and relationships of the heteromyid rodents. Ann. Carnegie Mus. 24, 73–262 (1935).Google Scholar

Copyright information

© Springer-Verlag 1973

Authors and Affiliations

  • G. J. Kenagy
    • 1
    • 2
  1. 1.Department of BiologyUniversity of CaliforniaLos Angeles
  2. 2.Max-Planck-Institut für VerhaltensphysiologieErling-AndechsFederal Republic of Germany

Personalised recommendations