The Metabolism of a Very Small Mammal

Abstract

Metabolic studies were made on a long-tailed shrew, Sorex c. cinereus, which is at the lowest limit of mammalian size. Its O2 consumption was measured in an automatic volumetric apparatus adjusted to simulate natural conditions. During an 11-hr. fast the shrew used 620 ml. of O2, representing an energy consumption of 54% of its metabolizable body substance, and 1.72 Cal./gm. day. The maximum intensity observed was 21.5 cc./gm. hr. or 2.37 Cal./g. day. The lowest rate of O2 consumption was 10.6 ml./g. hr., or 1.17 Cal./g. day. Because of extreme nervousness and constant need for food, measurements of basal metabolism comparable to those on other mammals cannot be readily obtained.