The Physiology and Energetics of Bat Flight

Abstract

ABSTRACT Bats are unique in being the only mammals capable of flight. The mobility, speed, and agility associated with this means of locomotion must have been an important factor in their successful radiation, which has made this diverse group the second largest order of mammals. Excluding man, and possibly rodents, bats have the widest distribution of any terrestrial mammals (Simpson, 1945; Walker, 1964; Anderson & Jones, 1967). Despite a growing literature on the physiology of resting or hibernating bats, almost nothing is known regarding the physiology or energetics of bat flight. Mammalian flight is of particular physiological interest since recent studies of bird flight (e.g. Tucker, 1968b, 1969; Berger, Hart & Roy, 1970) show that it requires a metabolic rate well above the maximum of which similar size, terrestrial mammals are capable during exercise (Pasquis, Lacaisse & Dejours, 1970). Furthermore, birds possess a number of adaptations for flight which are not shared by mammals. In the following research we have measured the energetic cost of flight to a bat and attempted to determine what adaptations permit these mammals to maintain the high metabolic rates for which birds seem so uniquely specialized. Some of the data which we report here were summarized in a brief preliminary report (Thomas & Suthers, 1970).