Head-body temperature differences in the Australian blue-tongued lizard, Tiliqua scincoides during radiant heating

When heated radiantly, head-body temperature gradients developed in both live and dead Tiliqua scincoides. The gradients were consistently larger in live than in dead individuals, indicating they were enhanced by a physiological component superimposed on the more basic physical components. Large gradients in the initial phases of heating represented a lag effect, the head core beginning to receive heat before the body core because it is closer to the heated surface. Once this lag effect subsided, the body heated more rapidly than the head because it presented a greater incident surface area per unit mass than did the head. Living lizards appeared to maintain head-body temperature differences until the maximum voluntary temperature was approached.