Here we show that constructal-law physics unifies the design
of animate and inanimate movement by requiring that larger bodies move farther,
and their movement on the landscape last longer. The life span of mammals must
scale as the body mass (M) raised to the power 1/4, and the distance traveled
during the lifetime must increase with body size. The same size effect on life
span and distance traveled holds for the other flows that move mass on earth:
atmospheric and oceanic jets and plumes, river basins, animals and human
operated vehicles. The physics is the same for all flow systems on the
landscape: the scaling rules of “design” are expressions of the natural
tendency of all flow systems to generate designs that facilitate flow access.
This natural tendency is the constructal law of design and evolution in nature.
Larger bodies are more efficient movers of mass on the landscape.