Design of the mammalian respiratory system. V. Scaling morphometric pulmonary diffusing capacity to body mass: wild and domestic mammals.

This paper utilizes a comparative approach to establish the relationship between morphometric diffusing capacity for oxygen (DLo2) and maximal oxygen consumption (Vo2max). DLo2 and Vo2max were determined on the same 21 individuals in African mammals spanning a range in body mass from 0.4 to 240kg. We confirmed earlier findings that Dlo2 was proportional to Mb0.99 while Vo2max was proportional to Mb0.79. Thus, the ratio of Dlo2/Vo2 is approximately proportional to Mb0.20. We conclude that large animals require a larger pulmonary diffusing capacity to transfer oxygen at the same rate from air to blood.