Standard Energy Metabolism of Marsupials

Abstract

IN 1902, Martin¹ reported that the metabolic rate of several Australian marsupials was approximately one-third of that of eutherian mammals. Since that time, this well known paper has been often quoted as showing that marsupials represent a level of physiological development intermediate between the “lower” monotremes and the “higher” eutherians, particularly in regard to temperature regulation. Recently, however, it has been shown that many marsupials can regulate their body temperatures as efficiently as most eutherians² and therefore Martin's results have been doubted. We have made a study to see if marsupials do have a lower standard (or basal) metabolic rate than eutherians, and to find the actual level of energy metabolism of marsupials in general.