Elaborate CNS cooling structures in large dinosaurs

Article metrics

Abstract

DURING sustained activity, or when exposed to high ambient temperatures, terrestrial animals often experience periods of core hyperthermia. The central nervous system (CNS) is very sensitive to elevated temperatures1–3, and consequently, both bradymetabolic and tachymetabolic4 terrestrial vertebrates have evolved physiological mechanisms which effect localised cooling of the brain, and thereby reduce any thermal impairment of CNS functioning. In modern reptiles this temperature gradient is produced by evaporative cooling from the buccal cavity and upper respiratory tract5,6, conducting heat from the brain through the floor of the cranium7. Mammals dissipate heat, by evaporation, from the nasal mucosa to the air flowing through the nasal passages. The cooled venous blood draining from this highly vascularised mucosa flows into the cavernous sinus, where counter-current heat exchange with the carotid arteries, elaborated into a rete in many forms, results in brain cooling8,9 (Fig. 1a). Dinosaurs would have experienced similar thermal problems to those of modern vertebrates, and these would have been particularly acute in the larger forms whose low surface area to volume ratio would have restricted dissipation of the enormous amounts of heat generated by the skeletal muscles during activity. It is therefore proposed that they required and possessed comparable physiological mechanisms to protect the brain during core hyperthermia.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1

    Percht, H., Christopherson, J., Hensel, H. & Larcher, W. Temperature and Life 656–658 (Springer, Berlin, 1973).

  2. 2

    Becht, F. C. Am. J. Physiol. 22, 456–476 (1908).

  3. 3

    Webb, G. J. W. & Witten, G. J. Comp. Biochem. Physiol. 45A, 829–832 (1973).

  4. 4

    Bligh, J. & Johnson, K. G. J. appl. Physiol. 35, 941–961 (1973).

  5. 5

    Crawford, E. G., Palomeque, J. & Barber, B. J. Comp. Biochem. Physiol. 56A, 161–163 (1977).

  6. 6

    Webb, G. J. W. & Johnson, C. R. Comp. Biochem. Physiol. 43A, 593–611 (1972).

  7. 7

    Crawford, E. C. Science 177, 431–433 (1972).

  8. 8

    Baker, M. A. & Hayward, J. N. J. Physiol., Lond. 198, 561–579 (1968).

  9. 9

    Hayward, J. N. & Baker, M. A. Brain Res. 16, 417–440 (1969).

  10. 10

    Romer, A. S. Vertebrate Paleontology (University of Chicago Press, 1966).

  11. 11

    Galton, P. M. J. Paleontol. 44, 464–73 (1970).

  12. 12

    Ostrom, J. H. Am. J. Sci. 262, 975–997 (1964).

  13. 13

    Ostrom, J. H. Am. Mus. nat. Hist. Bull. 122(2), 33–186 (1961).

  14. 14

    Ostrom, J. H. Postilla 62, 1–29 (1962).

  15. 15

    Young, B. A., Bligh, J. & Louw, G. J. Thermal Biol. 1, 195–198 (1976).

  16. 16

    Dodson, P. Syst. Zool. 24, 37–54 (1975).

  17. 17

    Hopson, J. A. Paleobiology 1, 21–43 (1975).

  18. 18

    Heath, J. E. Physiol. Zool. 39, 30–35 (1966).

  19. 19

    Bakker, R. T. Discovery (New Haven) 3, 11–22 (1968).

  20. 20

    Bakker, R. T. Nature 229, 172–174 (1971).

  21. 21

    Coombs, W. P. Paleogeogr., Palaeoclimatol., Palaeocol. 17, 1–33 (1975).

  22. 22

    Taylor, C. R. Physiol. Zool. 39, 127–139 (1966).

  23. 23

    Ostrom, J. H. Evolution 20, 290–308 (1966).

  24. 24

    Johnson, C. R. Comp. Biochem. Physiol. 43A, 1025–1029 (1972).

  25. 25

    Schmidt-Nielsen, K. et al. Condor 71, 341–352 (1969).

  26. 26

    Bakker, R. T. Evolution 25, 636–658 (1971).

  27. 27

    Farlow, J. O., Thompson, C. V., Rostner, D. E. Science 192, 1123–1125 (1976).

  28. 28

    Magilton, J. H. & Swift, C. S. J. appl. Physiol. 27, 18–20 (1969).

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Cite this article

WHEELER, P. Elaborate CNS cooling structures in large dinosaurs. Nature 275, 441–443 (1978) doi:10.1038/275441a0

Download citation

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.