Abstract: An animal exercising device for exercising an exercisable pair of legs of an animal as the animal walks across a surface. The animal exercising device comprises a frame structure positionable about the rear quarter of the animal, the frame structure including elastic rings for suspending the rear end of the animal therefrom. The rear legs of the animal are inserted into boots which are attached to crank arms. The crank arms are attached to wheels which rotate upon walking movement of the front legs of the animal. Upon walking movement of the front legs of the animal, the rear pair of legs attached to the crank arms are oscillated upwardly and downwardly by the crank arms for passively exercising the rear legs of the animal.