Biknevicius 9723768 The skeletal system of mammals is affected by a variety of factors, including body weight, locomotor forces, and limb posture. Whereas scientists are beginning to understand how these factors interact to determine skeletal form in adult animals with regards to bone stress levels, very little data is available to assess whether this mosaic of mechanical factors is equally important in determining skeletal structure in growing mammals. Preliminary data generated in my laboratory show that limb function changes with age during the first few weeks of locomotor function. The results of the proposed study will be used to test two distinct questions: how similar are the locomotor dynamics in adult and juvenile dogs ranging in size and shape when gaits are standardized, and are levels of bone stress comparable in juvenile and adult dogs. The general principles derived from this study will have practical uses in veterinary medicine, for clinical evaluations of the effects of orthopaedic treatments in young dogs, as well as evolutionary biology, because ontogenetic patterns established in living species often provide clues to the evolution of form-function complexes.