ABSTRACT
Life-sustaining and enhancing behavior, such as searching for food and avoiding predators, includes locomotion as an integral component. Nature has evolved a variety of forms of locomotion, such as flying, swimming and walking, suitable for different environments inhabited by the animal and machinery for implementing this important motor act. A common feature of all forms of locomotion is repetition of cyclical activity of appendages to transport the body. Interestingly, except for organisms such as bacteria, the natural kingdom is without wheels, which we hold as the cornerstone for efficient transportation. Lack of physical fusion between the wheels and the body required by design would also stop the transmission of nutrients and neural command signals to the motors driving the wheels.1 Although wheels involve minimal accelerations and decelerations during a cycle, reducing pitching motion, legged locomotion offers unique advantages. The ability to step over or under obstacles and use isolated footholds allows legged animals to traverse terrains that are virtually inaccessible to wheeled vehicles.2
