Evolutionary rigidity of thermal physiology: The case of the cool temperate lizard Lacerta vivipara

We compared the thermal dependence of sprint speed in two populations of the common lizard, Lacerta vivipara , from different altitudes. Although field body temperatures in the montane population were consistently 3-5 degree C below those of the lowland population, we found no parallel shift in the optimal temperatures for sprint speed. Lizards from both populations also selected similar temperatures in the laboratory. In the field, lizards from the montane population were frequently active at body temperatures the seriously impair locomotion. These observation give support to the static view of thermal physiology, which claims that thermal physiology is evolutionary, stationary and resistant to directional selection.