In recent years, the thermal relations and the thermophysio­logical responses for representatives of the lizard families Agamidae, Varanidae 5 Iguanidae, Anguidae, and Scincidae have been studied. Substantial field and laboratory observations have established that although lizards are ectothermic, they behaviour­ ally adjust and maintain their body temperatures (TB), under favourable macroclimatological conditions, within a certain range. The ranges of 'optimal' or 1 preferred 1 TB vary interspecifically even in the same environment. The physiological significance of these preferred TB has received considerable study only in the last decade. Most of the attention has been directed toward their physiological performance at non-injurious TB (particularly high TB) and heat resistance. There is a paucity of literature on the physiological responses of lizards to low TB.

The thermoecology and physiology of New Zealand lizards have not been studied. Work on congeneric species is also limited. Most of New Zealand‘s lizard species are viviparous. Viviparous l1zards do not appear to be limited in latitudinal distribution but are excluded from extreme environments of polar and desert regions. Oviparous species, however, are restricted from cooler regions where individuals can exist but where successful breeding and development cannot occur.

The underlying objective of this study was to test the hypothesis that New Zealand lizards are physiologically adapted to be active at low TB. For this purpose, a single species was chosen and the scope was limited to intact animals with the emphasis on relating and comparing data with other work on lizards.