Blood Flow to Appendages and the Control of Heat Exchange in American Alligators

Small American alligators (200-400 g) were heated and cooled from 20 to 35 to 20 C in a temperature-controlled wind tunnel. Blood flow to the limbs and tail was periodically occluded, using remotely controlled occlusion cuffs. When blood flow in all appendages was occluded, the rate of heating was significantly reduced from that when blood flow was unrestricted. The rate of cooling was not significantly affected by occlusion of blood flow in all appendages, however. Blood flow to appendages, rather than a generalized perfusion of the skin, appears to be primarily responsible for the differences in the rates of heating and cooling in alligators.