Nature 244, 181 (20 July 1973); doi:10.1038/244181a0

Anatomical Evidence for a Counter-current Heat Exchanger in the Leatherback Turtle (Dermochelys coriacea)

ALLEN E. GREER JUN.^*, JAMES D. LAZELL JUN.^† & RICHARD M. WRIGHT^‡

^*Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts 02138
^†Massachusetts Audubon Society, Lincoln, Massachusetts 01773
^‡Department of Biology, Boston University, 2 Cummington Street, Boston, Massachusetts 02215

FRAIR et al. ¹ have recently given strong circumstantial evidence that leatherback turtles (Dermochelys coriacea) can maintain a deep body temperature at least 18° C higher than the ambient temperature of cold water. The mechanisms underlying this differential are largely unknown but are presumed to be muscular activity combined with the thermal inertia of a large body mass and an insulating layer of subepidermal fat¹. Countercurrent flows have also been suspected as a heat retention mechanism¹⁻² but so far have not been proved. We now present anatomical evidence for a countercurrent heat exchanger in the front and rear flippers of a leatherback turtle, which is the first evidence for this kind of heat retention mechanism in a reptile.

References

1.	Frair, W., Ackman, R. G., Mrosovsky, N., Science, 177, 791 (1972).
2.	Mrosovsky, N., and Pritchard, P. C. H., Copeia, 624 (1971).