SHORT COMMUNICATION THE RELATIONSHIP BETWEEN BODY MASS AND VENTILATION RATE IN MAMMALS

The resting, specific metabolic rate (rate per unit mass) and rate of oxygen consumption increase with decreasing body mass in mammals (see Schmidt-Nielson, 1984, for a review). Since lung volume is linearly related to body mass (Tenney and Remmers, 1963), the increased demand for oxygen in small mammals is met by an increase in ventilation rate, rather than by an increase in respiratory volume. The study most frequently cited which relates resting ventilation rate to body mass is that of Stahl (1967). In the course of completing an earlier project (Altringham and Young, 1991), we had reason to look at Stahl's paper in some detail, and identified a number of potential problems, which cast some doubt on the value of the results. Stahl used data from the literature in determining this relationship, and a study of the source material shows that the physiological state of the animals is very variable. The measurements are incidental to other studies, some animals are restrained, in others breathing was measured by invasive methods, and the variation in resting ventilation rate is often very large. No graph is provided, few raw data are included, and it is unclear what size range o