Metabolic scaling

Metabolic scaling refers to the relationship between an organism's metabolic rate and its body size, typically described by power-law relationships. The most well-known form is the 3/4 scaling described by Kleiber's law, but metabolic scaling encompasses a broader range of exponents and contexts, including the scaling of maximum metabolic rates, field metabolic rates, and the metabolic costs of specific activities like locomotion and thermoregulation.

The theory behind metabolic scaling connects directly to the fractal network model of allometric scaling, which treats metabolic rate as the throughput of an optimally designed transport network. From a systems perspective, metabolic scaling is not a biological accident but a constraint on any system that must distribute energy through a hierarchical network in three-dimensional space.