Abstract :
We discuss the problem of observation of natural similarity in skeletal evolution of terrestrial mammals. Analysis is given by means of testing of the power scaling laws established in long-bone allometry, which describe development of bones (of length L and diameter D) with body mass in terms of the growth exponents, e.g., λ=dlog L/dlog D. The bone-size evolution scenario given three decades ago by McMahon was quiet explicit on the geometrical-shape and mechanical-force constraints that predicted . This remains too far from the mammalian allometric exponent λ(exp)=0.80±0.2, recently revised by Christiansen, that is a chief puzzle in long-bone allometry. We give therefore new insights into McMahonʹs constraints and report on the first observation of the critical-elastic-force, bending-deformation, muscle-induced mechanism that underlies the allometric law with estimated λ=0.80±0.3. This mechanism governs the bone-size evolution with avoiding skeletal fracture caused by muscle-induced peak stresses and is expected to be unique for small and large mammals.
