A unified formula for calculating body surface area of humans and animals.

We previously derived a formula for calculating human body surface area (BSA) from V (body volume) and L (reference body length): BSA=(9 pi VL)(0.5). In this paper, we analyse first the effects of body density variation on BSA during growth and the scaling relation of BSA to body mass. Then we utilise the derived formula to calculate BSA of animals and compare the obtained data with the direct measurements on the same animals, including rat, chicken, dog, and cattle, from the literature. It is shown that two problems remain to be solved for applying the derived formula to all mammals and other animals: one is to find out the L for each species of animal by means of direct measurements, and the other is to obtain the variation of body density during growth.