Zoological Institute, Russian Academy of Science, Universitetskaya nab.1, St.-Petersgurg 199034, Russia

Abstract

The pterosaurs wings seems to be dimensionally anomalous compared to the modern birds with flapping flight, but more adequate to gliding or soaring birds and aircraft deltaplans or gliders. The minimal energy requirement for avian flapping flight is 30-100 times higher than resting metabolic rate in recent reptiles and 5-10 times greater than their aerobic energy output in maximal locomotion activity. The minimal energy costs of soaring flight in birds are only 2-2, 5 times higher than maximal aerobic energy output in recent reptiles. If pterosaurs could increase their aerobic energy output up to 20 standard metabolic rates and invest their anaerobic capacity, they could generate over short period of time as much energy as it is necessary for flapping flight. In contrast to birds and mammals, reptilian equations of metabolic rate versus body mass have higher slope coefficient and so, the increase in body size in flying reptiles is less limited.