The famous law governing how much energy every animal needs is caused by how blood pulses, not the shape of the blood vessels.
April 14, 2026
Original Paper
The Dynamic Origin of Kleiber's Law
arXiv · 2604.10476
The Takeaway
For decades, scientists thought metabolic rates were determined by the fractal 'tree' shape of our internal networks. This study proves it is actually about wave-impedance—essentially how fluid pulses through us—overturning one of the oldest consensus theories in biology.
From the abstract
The ubiquitous $3/4$ metabolic scaling exponent, known as Kleiber's law, has long been attributed to the minimization of viscous dissipation within fractal transport networks. In this paper, we invert this standard narrative, demonstrating that Kleiber's law is fundamentally a signature of pulsatile wave physics rather than steady-state geometry. By coupling local branching optimization to global allometry, we derive the exact generalized metabolic exponent $\beta = d\alpha/(2d+\alpha)$, which s