Seasonal variations of the oxygen consumption and the blood glucose concentration under low temperature conditions in the male tortoise, Testudo hermanni hermanni GMELIN

Tortoises (Testudo hermanni hermanni) which are cooled down to 5 °C show a considerable higher oxygen consumption during the first week at this temperature in June and August than in November, which is the time when hibernation normally starts. Prolonging the low temperature conditions in spring leads to an increase in oxygen consumption. The blood glucose concentration is reduced during normal hibernation, but can rise quickly when the animals are disturbed. During cold torpor induced in June and August the blood glucose concentration is drastically increased. The results support the hypothesis according which hibernation in the tortoise is the result of a metabolic preparation in autumn and cannot be induced artificially during spring and summer. Endogenous factors are involved in the termination of the physiological phenomena of hibernation in spring.