What we did

There were two concerns with the claims of greater influence of circulation on heat budgets ar larger body sizes. First, the control of conditions for heating and cooling was not the best it could have been. Second, the experiments did not account for the effects of size on body shape.

Our solution to these concerns was to carry out our heat transfer experiments in a large wind tunnel where we could vary the importance of wind speed (which would mediate the balance between radiative and convective heat exchange), and vary the temperature of the air quickly. In this way, we could cycle animals' body temperatures between warming and cooling.

We also carried out careful measurements of superficial temperature gradients within the limbs and between the core and skin of the trunk. This would enable us to better measure the temperature gradients driving heat exchange and gauge the likely effects of cutaneous circulation on them.

Further reading

Spotila, J. R., O. H. Soule, et al. (1972). The biophysical ecology of the alligator. Heat energy budgets and climate spaces. Ecology 53: 1094-1102.

Blood flow pages

Heat exchange

Why alligators?

What we did

What we found

Implications