title: A general basis for quarter-power scaling in animals.
abstract: It has been known for decades that the metabolic rate of animals scales with body mass with an exponent that is almost always <1, >2/3, and often very close to 3/4. The 3/4 exponent emerges naturally from two models of resource distribution networks, radial explosion and hierarchically branched, which incorporate a minimum of specific details. Both models show that the exponent is 2/3 if velocity of flow remains constant, but can attain a maximum value of 3/4 if velocity scales with its maximum exponent, 1/12. Quarter-power scaling can arise even when there is no underlying fractality. The canonical "fourth dimension" in biological scaling relations can result from matching the velocity of flow through the network to the linear dimension of the terminal "service volume" where resources are consumed. These models have broad applicability for the optimal design of biological and engineered systems where energy, materials, or information are distributed from a single source.
authors: Department of Physics, Pennsylvania State University, University Park, 16802, USA.
authors: Jayanth R
authors: JR
authors: Banavar
authors: Melanie E
authors: ME
authors: Moses
authors: James H
authors: JH
authors: Brown
authors: John
authors: J
authors: Damuth
authors: Andrea
authors: A
authors: Rinaldo
authors: Richard M
authors: RM
authors: Sibly
authors: Amos
authors: A
authors: Maritan
mesh_terms: D000818:Animals; D004734:Energy Metabolism; D008962:Models, Theoretical