Metabolic rate and body size relationships in adult and growing homeotherms

Abstract

In adult homeotherms the basal metabolic rate (BMR) changes pro- portionally with approximately 0.75 power of the body weight so it is possible to accept the kg0-75 as metabolic unit of the body size. When the data on the BMR of adult homeotherms are expressed per this unit one can distinguish several metabolic levels characteristic for different groups of homeotherms. In growing homeotherms the relationship between the BMR and body weight even on a log. log. plot is not represented by a straight line. For this reason discussed relationship cannot be characterised by a single regression coefficient. It is con- cluded, therefore, that the analysis of intraspecific relation between BMR and body size with the help of equation M=aW*> should be dis- carded as not giving clear and easily comparable results. In com- parative studies the metabolic rate of growing homeotherms can be expressed per common metabolic unit of the body size i.e. kg0-75 be- cause this approach enables to compare the metabolic rates, both intra- and interspecifically.