Kleiber's Law (2D): Metabolic Scaling Across Body Sizes

Every living thing burns energy to stay alive, but the rate scales with body mass in a curiously specific way: basal metabolic rate is proportional to mass raised to the 3/4 power, not to mass itself. This simulator renders that relationship as a real 2D log–log plot — a body-mass slider spanning shrew to elephant moves a glowing marker along Kleiber's curve, recomputing basal metabolic rate, mass-specific energy cost and an allometric heartbeat pulse in real time. Switching between mammal, bird and ectotherm taxa swaps the underlying power-law coefficients, and an ambient-temperature slider drives a Q10 thermal-scaling response for ectotherms only — a direct, hands-on illustration of why small warm-blooded animals eat almost constantly, why cold-blooded metabolism rises and falls with the weather, and why the naive 19th-century "surface area" hypothesis for metabolism was eventually overturned by Kleiber's mouse-to-elephant curve. Drag to pan the axis and scroll to zoom in on any region of the curve.